For the last quarter century, I’ve been lurking on every forum not only for each car or bike I own, but every car I’ve designed parts for. Mostly it’s to check that I’m not responsible for some series of horrific failures (I’m not! So far…), but I’ve never found one post, not one, praising the elegant and efficient design of a fuel pipe bracket or whatever. Not even the AC pump replacement bracket for the V6 Exige, and that was really neat. What I have found is so many questions that could be answered by reading the manual, so many terrible pieces of advice, so many wrong conclusions, and the one thing that keeps cropping up again.
That thing is the idea that cars are designed to fail the second the warranty runs out. That phrase “designed to fail” really gets to me. I take it very personally when someone suggests that I have deliberately set out to ruin their car the second their eligibility for free repair runs out.
When we start designing a car we have a set of durability targets that we have to beat. These are never defined as “must fail after,” but instead are “must still exceed this spec at the end of testing.”
[Dave Larkman is a mechanical design engineer who had a 25-year career at Lotus Cars and Lotus Engineering (the consultancy business that worked for other OEMs), eventually becoming Lead Engineer of Powertrain Design. He has also been a semi-pro drifter, rides sports bikes, and used to feel ashamed about his taillight collection until he found Jason Torchinsky on the internet. Wait, why am I writing this in third person? It’s me, Dave, writing my own bio. – DL [Ed note within ed note: You know Dave from his excellent article “I Was So Bored At Work I Redesigned A Tiny Engine Part For Fun And Accidentally Saved 22,000 Pounds Of Aluminum.” -DT]]
Many Parts/Systems Are Designed For Conditions Far Tougher Than Your Commute
A good example is a 1,000 hour idle test on engines. Idling is really tough on engines because at idle, the oil pump is doing its worst work, so any slightly moody bearing surfaces are going to get destroyed. I’ve seen a poorly heat-treated camshaft lobe wear out in just six hours of idling, to the extent the valve wasn’t opening at all, but the pass criteria on that test is that at the end of the test, the bearing faces must still be within the size and surface finish tolerances of a brand new part. As new, at the end of the test.
That test seems weirdly arbitrary, doesn’t it? 1,000 hours is a nice big round number. Engine testing is the result of a thing called Design Failure Mode Effect Analysis (DFMEA), where we sit down before the start of the project, write down everything that might go wrong, work out how severe it is, and how likely. A slight chance of a minor annoyance gets a low score, any chance at all of a safety or emissions issue and it gets a high score. Then we have to work out what testing we’d have to do in order to ensure that the design we come up with won’t suffer from the likely or severe failure modes.
The actual testing regimes are usually whatever we’ve proven to have worked well in the past. A 1,000 hour idle test sounds like something someone thought up because it’s a suspiciously round number, then found that poor parts fail, but good parts will pass. Job done.
A thermal cycle test is where we run an engine on a dyno at full load until the exhaust manifold is glowing red hot, then we turn off the fuel and spark, but keep motoring the engine at max revs to blow cold air through it, cooling it all down far faster than you ever could by driving it. Then repeat again and again, red hot to room temperature and back again. It’s horrific on exhaust components.
It’s also a 450 hour test, which sounds like the sort of number that’s not just plucked out of the air. Someone at some point either found that 1000 hours of this was impossible to pass despite the parts being OK for production, or that 100 hours was inadequate. Or maybe it’s just how long it takes to do 10,000 cycles. Either way, it tends to fail parts that won’t get failed by any other test, which is why it’s so useful. When your exhaust design stops failing at thermal cycle, you can relax.
Note that the target here isn’t to delay the failure until after the warranty period, it’s so that you can go to court with your DFMEA, drawings, and testing plan and say: We thought of this, we designed a solution, we tested for this, we can prove we took reasonable steps to ensure that this failure wouldn’t happen.
We don’t have an upper target for durability. Cars are almost infinitely repairable; with careful use and the right maintenance, you can get to 500,000 miles on pretty much any car, even one that I’ve worked on. But that maintenance is going to cost, which isn’t going to be acceptable once the value of the car falls below the cost of a new set of spark plugs (which is what happened to one of my old E30 BMWs).
We can make engineering decisions to keep that maintenance cost low, but every time it’s going to increase cost, and probably mass. I worked on an engine on which you could swap out the cylinder liners in half an hour — great for keeping maintenance costs low, but an utter irrelevance for pretty much every car owner on the planet. All engineering is a compromise, and anyone who says otherwise is trying to sell you something that’s very, very expensive, and also still a compromise.
The liners were made of glass, in case you were wondering; you had to pop them out for cleaning every few minutes of running time.
That’s a lot of text in one go, let’s break it up with a picture of some weird engine parts, all of which made it through testing first time without a single issue. Remember folks: Every bracket is already a design failure. (Brackets are inelegant).
These tests cost tens of thousands in prototype parts (look at how much aluminium they had to machine away on that big curved bracket – it started off as a rectangular billet), then more tens of thousands in labor to build, run, strip, and inspect. As a design engineer, you don’t want to waste that much money by getting it wrong, but that’s not the worst part of failing the test – those parts will also be fitted to the rest of the test engines, and test cars — maybe hundreds of them. If your prototype part isn’t durable, then that entire phase of testing can’t be done until you’ve fixed it; the knock-on cost is millions, or tens of millions.
So you do the analysis, you benchmark successful designs, and you hope that everything you design will be good as new at the end of whatever horrific accelerated life testing they throw at it. Sometimes it goes wrong, and there’s a combination of tolerance and assembly and testing that overloads something, or creates a weird resonant frequency, or maybe the guy doing the heat treating put a “before” cam in the “after” pile, but for the most part, you design for success, and expect to get it.
If you have a wacky new idea, you test it on research engines for years before risking it on a production project.
Design Engineer pay isn’t great, so we’d be open to the idea of a massive bonus for creating dealer service work, if such a thing existed. But often we don’t even work for the same OEM as the dealer network. With the amount of consultancy work and badge engineering going on, the link between the people who design your car and the people who will service it is tenuous. In fact, the only dealer feedback we get is “make servicing easy,” which we totally ignore just to infuriate the fifth owner sixteen years later (actually we agonise over that too – I still feel bad about the requirement to use a
crow’s foot to get to one of the inlet manifold nuts on supercharged 2ZZ Exiges, and that was over twenty years ago).
There is no motivation at all to design-in a lifetime limiting feature; it’s bad for us personally, in an immediate being-shouted-at way, and if that failure can cause an engine to stop, or a loss of vehicle control, then we know the guys who risk their lives testing the cars. Sometimes we are those guys.
While I always considered it deeply cool to get to do some testing or mileage accumulation, always in the back of your mind is “what if something important fails right now?” The pre-production cars have to pass a huge amount of testing before they’re allowed out in public, but when you’ve spent weeks in DFMEA meetings, it sticks in your head. You really don’t want anything to break, ever.
Designing Parts To Fail At A Specific Time Isn’t Easy
But. What if we were evil? What if there was some kind of incentive to create failures and drive up reliability fear in customers to increase extended warranty sales? Presumably in a way that wouldn’t also utterly tank actual vehicle sales. Could we do it?
I’ve designed parts to fail. They were shear pins, the things that let collapsible steering columns not spear you in the chest, but in my case, they were steel pins half a mile under the sea in an oil well drill pipe. So, I do the analysis, design the notched pins, design the housings to load them in shear, then test a bunch of them and get an unworkably huge range of results. Getting those pins to be strong enough not to break until we needed them to was a nightmare, and that was when we could create an overload to suit us. Trying to get that huge bell curve of actual part durability to start after the right time or number of cycles is pretty much impossible, and for that bell curve to be narrow enough for one of the wheels to fall off a significant number of customers’ cars the day after the warranty runs out is just impossible.
Then you have the problem of the customers’ use case. Say it’s 100,000 miles or three years, are those miles on a track or sat idling in traffic? Are those years parked at the coast going rusty or baking in the sun? Or I guess both if you aren’t in the UK. Designing something to fail in large numbers immediately after that time/distance, but not a minute/mile before, is just impossible when you have no control at all over the environment or customer abuse.
Even if it were possible, which it definitely isn’t, the OEMs would have to test everything not just to exceed the required durability, but then carry on testing to destruction. That would cost hundreds of millions more, and seriously delay the introduction of new designs by years, which would cost hundreds of millions more on top of the hundreds of millions you already spent making the project late, and all for no benefit whatsoever.
It Does Happen, But It’s Not Intentional, And It’s All Just A Compromise
If something goes wrong on your car, just out of warranty or not, it wasn’t intentional. We hoped it would provide so many years of reliable, loyal service that you’d tell all your friends to buy one too. We bet our careers on it. We get paid little enough that we drive fourteen-year-old Toyota-badged Subarus and really could have done without having to shell out for a new wheel bearing again this year; we feel your pain.
Top graphic images: DepositPhotos.com
Hi, this is Dave Larkman.
I’m sorry I can’t answer all your comments right now, as I’m in Tokyo without my laptop, and only have wifi at the hotel. Also it’s my honeymoon, so a load of staring at my phone is not going to go down well.
I’ll be back on-line properly at the weekend, after a 26 hour journey involving two planes, a bus, three trains and a Nissan Juke Nismo RS.
Please leave a message after the beep.
Beeeeeep.
But what if I need you to respond to my “First!” comment right this second? I bet you engineered this trip to coincide with the posting of this article so you would be offline exactly when I PERSONALLY need you the most. How evil of you!
(Jokes aside, thanks, this was an awesome article)
I’ve engineered none of this trip, I married a genius who’s done that for me.
I’ve just snuck off to read through some of the comments before we leave the hotel and lose wifi. I’m really enjoying them so far, but some of them deserve properly long answers. I’ll get on that as soon as I can. I can see why Adrian goes for curt sweary replies, it must save a bunch of time.
Must go, she’s worried I’ve been in the toilet too long (I’m sitting on the edge of the bath, not actually using the brilliant and disturbing robot toilet).
Let her know that you have a lot of new fans, and BTW, congrats on the marriage!
Duuuuude! You are in so much trouble with your bride. Bad idea
She just bought me an $800 bottle of whiskey, so I think I’ve got away with it.
We’re in Hong Kong airport, so that’s HK dollars, not US.
We’re trying to reach you about your car’s extended warranty
The top photo looks like Mercedes has been behind the wheel.
Re: Many Parts/Systems Are Designed For Conditions Far Tougher Than Your Commute
I recently binge watched a bunch of police pursuit videos and honestly was astonished at how well many cars remain drivable after some pretty brutal (but not quite precise) PIT maneuvers. Even (especially?) stolen Kias.
Oh I went down the “Police Chase Zone” rabbit hole recently. …and Arkansas State Popo seem to have a “nearly-no-restrictions-PIT-anything-that-moves-at-any-speed” policy. I’m an automotive engineer and spent most of my career in tribology (whether it be lubricants, coatings, etc.). My favorite is the car with one remaining tire, another wheel that is locked up with the wheel worn away down to a half-cylinder and yet the driver is still able to go 75 down the freeway. I imagine that would never work here in Michigan. You’d clip a massive pothole on that half-melted wheel and rip the car in half.
Thank you, Dave for illuminating an oft-misinformed if not willfully disinformed aspect of our industry. Agree 100% with everything you wrote.
If you ever see a GE locomotive (with the T-shaped rear) from the early-2000s era, ie., the Tier-2 GEVO, I can pinpoint you to parts in the engine of which I was personally involved in the design or managed the development, including the front-end cover, crankshaft, and oil pan (hoping there were no catastrophic crank failures or leaks!!).
And in my realm, electric aircraft, failure of any mechanical parts or electrical components can result in not only that aircraft crashing, but at this nacent point of electric vertical takeoff and landing aircraft, the entire industry would be impacted. The level of engineering and testing of components and assemblies is amazing from what I can see on the inside. And for good reason, the regulators also take this very seriously.
So can someone explain those EcoBoost engines where the water pump failure leaks into the oil and totals the engine? That’s not by design? Or did they think the water pump would never ever fail, in spite of a century of experience? And wet timing belts, whose bright idea was that?
In those the “normal” water pump failure (shaft seal) is a non issue, they designed a separate exit passage for it. The issue is that the coolant they used interacted poorly with the rubber gasket which sealed it to the block, and from going into the oil. They experienced failures because of that, and later switched coolant because of it. Theoretically if a car with that engine switched coolant to the good stuff early enough they would be okay.
A few years ago Cummins switched to a different polymer for their coolant hoses. The industry standard coolant had a pretty bad reaction to it. Guys were replacing hoses all the time. Cummins specified a nitrite free OAT type coolant and charged an arm and a leg for it. Fortunately, the aftermarket was able to start supplying it.
Yikes, I hadn’t heard of that but interesting nonetheless. Baffling to me that Cummins would want people to switch instead of finding hoses that work with the coolant everyone uses for big diesels.
Ford has had other issues with coolant in the past, in fact that contributed quite a bit to the plugging oil coolers on the 6.0 Powerstrokes (due to the coolant gelling), which would often start the cascading affect of overheating and cracking the EGR cooler and the engine ingesting coolant and popping the head gaskets. It wasn’t the only source of the failure, just a really big one. Most people running that engine today flush the system and switch to the standard ELC HD Diesel coolant. Ironically, International used ELC coolant in their version of the 6.0, the VT365, and those engines experienced considerably less failures partially because of that. Ford used their coolant mostly because that’s what they had for everything else and presumably wanted to keep it uniform.
Source: I own a 6.0 Powerstroke and have spent way too much time researching everything to keep it in tip top shape.
Some design decisions are indeed baffling and vexing to car owners and other engineers in the industry alike, eg., the oil-wetted internal engine belts in the very same Ecoboost engines, but even in these seemingly absurd cases, we engineers can at least rationalize the reasons for these decisions.
As Dave says, ours is an industry of competing demands and the compromises that must be made to address them.
We engineers (usually) get it. Almost always, these decisions can be traced either to reducing cost, even if it’s a matter of pennies saved per piece; reducing a fraction of percent fuel consumption; reducing a fraction of a dB of noise; or meeting stringent emissions regulations by the slimmest of margins (and have to remain that way for over 120,000 miles).
Sometimes, though, engineers simply make wrong, objectively stupid, and even illegal decisions, eg., Dieselgate – I should know given my screen name LOL
I think all automakers in good faith want their customers to be happy with their products and come back to buy more cars for them again. Although I have never encountered an OEM express the requirement that their products last forever, the converse is also not true, as Dave so eloquently elucidated.
Gonna guess that Lotus Cars bean counters and buyers have different mentalities than those who count beans for the Big 3. Anything to save a quarter dollar. Five bucks, astounding! Read the book Savage Factory. It’s not as bad now, but if a transmission failed past 12k miles then, “not their problem.” There is that mentality today, but the 12k is now higher.
It’s much, much, much smaller than that. “Design Optimizations” that take weeks of work are pursued to remove $0.10 per part. When you’re building 200k of a thing per year, for 10 years, that’s $200,000 saved. Removing one bolt is over $50k a year.
It just occurred to me it would be to expensive to design all these parts to fail right after warranty. However design one part to fail that makes it look like operator error that isn’t covered under warranty is easier and cheaper. Like maybe eliminate grease fittings and say it is lubed for a lifetime. Said lifetime the life of the grease. Or get rid of dip sticks. We don’t need to worry about oil and transmission fluid it will be fine.
That is where they get you.
J/K
I think instead it is a case of the part is designed and tested and based on the results the warranty is set at something a little bit less. I mean a good warranty sells the car. We used to get 12 months and/or 12,000 miles. Now used cars get that. But people are always into conspiracies. If you want a real example of building to last just past the warranty look at what Jasper has become. I got an engine from them with 2 replacement engines because of build failure. It might have been more but then the transmission went I bought a replacement and it failed before the warranty. I just took a payout and bought a better truck
My uncle crewed on a privateer race team that went to Lemans a few years and for a while was the most successful team running Porsche 930- 935s. including one that entered 70 races and covered 40,000 in competition.
Hans Mezger, the designer of the original 911 engine that the 935 was based visited them and they were showing what they were working on and how amazing it was that they were getting over 800 horsepower out of the engines that could reliably run for 24 hours.
Hans Mezger said that it was a little embarrassing, and that in 1960 when he was designing the engine for producing 130 horsepower they didn’t have a big testing budget so they did a little testing at a target of about 200 horsepower. Then they just made everything a little stronger. They hoped for a margin of error allowing for eventual racing development. He said that a margin of error that included 850 horsepower developed from an engine designed for 130-200 horsepower was unacceptable.
I think this was like Germans complaining when their cars still ran after the fuel gauge reads empty,
Funny last line, I needed a chuckle
That was a great read. And it’s the truth. But I’ve also seen repair bills on modern BMWs rubber parts that all seem to start to go in the 50-60k mile range, and it’s still painful. I’ll just stick to my Japanese cars.
People who say that parts are engineered to fail right out of warranty and aren’t making a joke tend to be a certain type of person nobody should really listen to. I highly question that German engineers put any consideration for ease of maintenance, but I would definitely believe they intentionally do the opposite.
If you have thousands of parts and they were designed to fail after x number of cycles, some of the parts would last forever, most would fail when they were designed to, but one random part would fail almost immediately. This is not good.
Remember there are thousands of things that you can die from, but most people only die from one of them.
I’m not disagreeing with the article in regards to failures and only half-jokingly disagreeing that engineers consider serviceability when German cars are concerned.
Well Toyota and to a certain degree the Germans tave the attitude that if a part is designed to last forever, who cares if you have to dissemble the entire car to replace it, or failure cascades throughout the entire engine. Plastic cooling pipe inside the crankcase? Who came up with that idea?
Wear items like filters that require the disassembly of the dashboard is a good one to.
My buddy is a Lexus Master Tech. This is the answer. Same with the Germans, albeit with a euro flair. The Germans expect perfect servicing and build that into their designs, if you service a German car religiously, it’ll last forever. It’s built to not need repaired, and when it inevitably does, it’s complicated. Only thing I can’t seem to figure out is the fact that timing chains still stretch and have issues.
Even Toyota has their failures. A friend of mine just spent 10k having his LS460 fixed. And my master tech friend sold a timing chain job on another LS460 recently.
If I were an engine designer I would put a couple externally adjustable chain tensioner screws to take up slack and allow for adjustment of the cam timing. Seems like it would be simple enough, but it would probably interfere with the campaign to put degradable plastic doing important stuff while immersed in crankcase oil deep inside the engine.
Scratches head . . . shit, is that dandruff? Anyway, Germans seem to have missed the part about designing parts to last forever or even a reasonable amount of time by current industry standards. I’ve seen quite a few seemingly sadistically located parts (and requiring non-standard tools when it is unnecessary, which is also not to the benefit of servicing) that failed earlier than in much cheaper cars that require disassembling the entire front end to replace that were quick jobs on properly engineered vehicles even if they were hardly necessary as failure rates are much better. Maybe it was better prior to the millennium. Certainly many of their cars were actually desirable prior to ’00 (though MB was slipping in the back end of the ’90s).
Blame Chrysler.
Also blame European mandates to make cars easier to recycle (as in crush and shred) and the parts that are not recyclable biodegradable.
It’s hard to make something last forever when it’s literally designed to rot.
MB was declining before the merger and many Chrysler fans would blame DB for taking money from Chrysler to prop itself up, causing their decline. While I think they’re correct about DB neglecting Chrysler for the sake of itself, Chrysler was in a tough position at the time (which happened about every decade), so I don’t think Chrysler would have been much better without the merger. There are also the BMW and VW groups. VW is what I was thinking of specifically (though I was thinking of BMW with the comment that they used to be desirable).
Recycling mandates are far too recent to blame and something being recyclable doesn’t mean it’s got to be bio degradable or break down any more readily. The primary recyclable materials exposed to the environment are the same as everyone uses—steel and aluminum. Thermoplastics need to have recycled plastic content, which compromises its strength, but are primarily used for cosmetic body panels and don’t their famously superior engineers relish conquering such a challenge?! For companies challenged by the standard of recyclability, some of them use a lot of carbon fiber (doesn’t seem to bring down their absurd weights), which is often for cosmetic purposes and isn’t very recyclable. They also have the option to pay into a fund, so maybe that’s how they get away with the CF. If their cars are falling apart more readily after the mandate, then I’d expect a case of malicious compliance to push a narrative that the law doesn’t work is an attempt to get it repealed to save money. None of this has anything to do with why they can’t make a simple timing chain guide that lasts (unlike almost everyone else) or why their implementation of GDI—an invention they pioneered in the 1940s—gave the technology for the whole industry a reputation for problems and required valve cleanings that mostly only German (or Korean) cars suffer from, why they go out of their way to use non-standard hardware (BMW even recently patented a new design) when standard would be cheaper and more serviceable with absolutely no loss of durability, or why they design something like an alternator installation that requires the entire front end of a car to be removed to replace and then seemingly spec it to have a lifespan 1/5 that of a typical Japanese car that costs 1/3 as much, or countless other things over the decades, some of which are elementary school tech, like oil pickups. I’ve seen far too much head-slapping hack/intentionally poor design on VW/Audi trash products to believe German engineering is anything but the result of good propaganda. Totally washed away the good feelings I had about German cars from what MB made until about the mid-late ’90s.
I was thinking specifically of between about 1991 and 1996, when Mercedes-Benz used that biodegradable, soy-based insulation on engine wiring harnesses that deteriorated when exposed to heat or mice.
There’s also something about adhesives that I can’t remember, and some other plastic bits.
Oh, I forgot about that soy crap! What a terrible idea. Not bad to come up with in a brainstorming session, but even if it got to the prototype stage, testing should have picked up on how bad that was. I think Ford was/is using something derived from soy for cushions, which might be fine if it passes the same testing as the synthetic material it replaces, but wires? That’s a very small benefit considering all the other materials creating a likely bigger environmental problem by degraded wires making an otherwise fine car too expensive to repair. And do they not have mice in Germany? Just a few weeks ago, I had this weird, terible smell from my engine compartment after long drives. Couldn’t find anything leaking or worn and I was shaking my head in annoyance (I’d pull out my hair, but it’s already barely hanging on) as there was obviously something making that smell when I spotted some shredded paper and insulation on top of the right head, under the intake manifold. When I finally dug the entire nest out with various picks and a high pressure air blower, I had a pile that included a bunch of assorted synthetic fabrics and such. Nothing dead, but the smell hasn’t come back, so I imagine that was it. Luckily, I checked for chew damage and couldn’t find anything (they nested near one of the computers, too!), but I can imagine the problems if I had soy wires. I was able to drown 3 of them in a bucket trap and I hope that was all of them. There aren’t many creatures I hate, but mice are up there with ticks and mosquitoes and I’m not sure of that order because for all the damage they do to peoples’ health, the latter two didn’t help destroy my favorite car.
God that sounds like the Germans. Kinky and masochistic… but let’s not talk about their clubs. With their cars it’s usually something stupid like a 6 dollar grommet. The issue is it’s in the middle of the V and half the engine needs to be disassembled. It’s either that or vacuum lines and or something equally as stupid. Every time something broke on a German car my fam owned it was stupid.
That drives me nuts. OK, I get they have budgets and need to cheap out in places, but make those things accessible for replacement, then. Few things are more frustrating than a cheap part that costs a full day’s labor or more to replace. You almost want it to be an expensive part at that point!
And obviously these same principles apply to the Jatco Xtronic CVT, proving the haters wrong once again. Typical!
As a long time planetary automatic trans developer, I believe the issue with CVTs is they are much less tolerant to conditions like worn out fluid and low fluid levels due to leakage. Unfortunately (probably due to competitive reasons) the manufacturers seem reluctant to specify frequent service intervals that would keep them working.
Oh! Someone who can tell me why there aren’t any manual planetary transmission, ie without a torque converter. I mean there’s Lenco, and various tank transmissions, and bicycle transmissions, but not much in between.
Designs tend to evolve over time to what works best at a reasonable cost. The torque converter in front of a planetary gearbox is a great example of that. The torque multiplication and smooth operation of a torque converter justifies its additional cost over a dry or wet input clutch.
Oh I know that, it’s more like why didn’t constant mesh planetary gears and clutches make gear boxes with lay shafts and dogs etc obsolete? Instead we get double clutch transmissions.
The Wilson and Cotal transmissions seem like better ideas with modern metallurgy, and better electronics in the case of the Cotal.
You’re back! I haven’t seen you in a while, and I thought we lost you. <3 Last thing I want to do is scour a junkyard for another Jatco Xtronic CVT, because, obviously, none of them end up there!
We were talking about parts lasting past warranty
I’m not going to go miracle max’s wife on you, and respect Lotus engineering.
However, people are people, engineers included, and make mistakes. I suspect most of the egregious design failures that I have come across were due to a project manager ( that needs to consider the entire assembly ) not considering how problematic foreseen maintenance would be. Many components have become unserviceable, and need to be replaced (BMW$500+electric water pump, most CVTs ). Routing the exhaust directly under the oil pan, Saab had the oil pan curve around it for clearance, how does that not get called out? I don’t like my oil baked. Jaguar X type transmission pan gasket replacement(common failure)- like 20hr. procedure unless you drill an access hole through a flange to get to that one bolt on the pan, there were many more that I have blocked out, and it has been years since I’ve cursed the bastards that designed such. My biggest complaint by far is turning all cars into mobile Ipads that will age poorly.
Just remember everything from engineers to doctors for every one that has someone who graduated at the top of their class they have someone who graduated at the bottom of their class.
Things that make you go hmmm!
Wife happens to be in big wig manufacturing.
Modern parts are not designed to break down, they are designed to last X cycles. X just happens to be close to the end of warranty.
Same applies to computer screens, which we now see in cars too.
How many parts truly go into manufacturing a big wig? Shirley they can design them to last forever.
Id assume wig big manufacturing has an endpoint too. Glue has expiration dates.
About 150k parts if you count the individual strands, but consider the base as one piece. And don’t call me “surely”.
They probably could, it’ll just cost 2-3x as much…. And don’t call me Shirley…
Wasn’t it also Colin Chapman of Lotus fame who said something to be effect of, “if a car didn’t completely fall apart after it crossed the finish line, it was over-designed and too heavy”? I’m sure Dave L can confirm, correct, or outright refute that.
There is a lot of similarity between automotive and aircraft in this regard.
Aircraft can easily get 30+ years of service, as can any car.
However, planes have heavy maintenance schedules where you are inspecting, preventively replacing parts, and often stripping and re-applying paints and such. Often, airlines will replace the interiors at the same time.
Most aircraft have a 10 or 12 year heavy check schedule, that’s what we design for lifeing of parts.
Imagine how long a car would last if you (on a 7-8 year schedule) completely stripped it down to the chassis, overhauled the entire power train and suspension and proactively replaced another third of the parts. Plus replace all the interior except for the dashboard. Oh, don’t forget to acid dip the body, re-galvanize it and paint it.
It all boils down to money. There’s a business case that works for planes as they create revenue for airlines. That business case doesn’t exist for cars.
Most airliners have a service life determined by how many times the fuselage goes through a pressure cycle annd develops fatigue cracks. Everything else can be replaced until it becomes unprofitable.
That’s what was great about old Mercedes Benz diesel cars. They would last forever, and were designed to be easy to service.
Meanwhile they are parting out Airbus A321neos that are only six years old.
Which is a shame, A321neos are really nice, and are my favorite plane for domestic flights.
The story talks about how it should go. This talks about active cheapening on purpose. https://www.youtube.com/watch?v=NPbWHAE4RPM
I believe this article up to the point of corrosion resistance.
When every car and truck in the rust belt seems to start to look like swiss cheese after 6 or 7 years, you can’t get me to believe there isn’t a solution out there where structural metal couldn’t survive two to three times longer than it currently does, and bodies couldn’t be made of composites (remember Saturn?) that would last 20+ years and still look new.
https://www.theautopian.com/check-out-these-three-insanely-rusty-michigan-trucks-that-are-somehow-legal-to-drive-on-the-street/
Why should everyone have to pay more for a car because some states CHOOSE to throw corrosive substances on the road that they know destroys cars?
If they didn’t salt the roads in far northern Wisconsin, many people would have to stay in their homes for months out of the year with no public transportation or delivery services in many of the small towns.
Two weeks ago we got 43 inches of snow over the course of 4 days. The plows and salt trucks were out pretty much around the clock just trying to keep the roads passable.
I’m 55 years old and I have yet to have an engine fail in any of my (mostly GM) vehicles. I’ve had quite a few where I’ve had to get rid of them due to rust but they still ran just fine. Vehicle bodies and frames could be designed to last longer, but there’s no incentives for the manufacturers do this.
If trucks didn’t rust out after 10 years, many people around where I live would keep their vehicles longer. Then manufacturers wouldn’t sell as many of them.
I grew up in Michigan and thought the same until I moved West. Passes around here get 450 or more inches of snow per year including big dumps like you described and the roads stay open without the use of salt. The difference is that cars are required to use snow tires or chains.
Salt also doesn’t have to be a death sentence for cars. My father is daily driving a 2000 Silverado that is basically rust free in Michigan. He got tired of having giant rust holes in his cars so he bought an unlimited monthly car wash pass and now has the truck washed at least once a week in the winter time.
He is still shocked when he comes out to visit and sees old cars from the 70’s and 80’s still on the roads here being daily driven.
We bought our house in 2009 because it had room to park 5 vehicles (6 now) and specifically because there was a great carwash only a block down the street.
In 2012, something broke in the water reclaiming system in that car wash. The owner claimed it would cost him $100K+ to get it rebuilt to the current EPA/DNR standards. He said he was never going to get enough return on that kind of investment for banks to loan him the money, so the place closed.
Now the nearest car wash is 7 miles down the highway and we have to drive on salty roads to get there and back. When it gets below zero, the roads aren’t so sloppy, but the car washes usually close when it gets that cold. So my 2010 truck no longer has rocker panels.
Time to talk to your DOT about getting rid of the salt then. It really isn’t needed.
A regular program of running a car through the car wash to remove the salt would help a lot. However no one wants to pay $10 a week to maintain a car until it is rusted out. Have they done studies of car washes that recycle their water and see if it removes the salt from the water? I am surprised that car washes don’t offer a basic rinse from top to frame to generate business in the winter
See above post:
(https://www.theautopian.com/no-car-companies-dont-design-parts-to-fail-the-second-the-warranty-is-over/comment-page-2/#comment-922358)
I do wash our vehicles a couple of times per month, when they’re open during the winters, but I wish the one down the street hadn’t closed so we have to get them all full of salt again on the way back from the car wash.
In the land of eat cheese or die?
https://www.wisfarmer.com/story/news/2025/02/26/green-county-uses-cheese-brine-to-save-money-on-winter-road-clearing/80118508007/#
Lots of places find salt their roads without problems. Road salt is monumentally stupid.
Also it destroys roads and bridges, and is over all a huge waste of money compared to the alternatives.
I still think that would cause vehicles to rust.
From the article:
“Narveson says Grande employees fill a county-owned tanker truck with brine filtered for any solids and blended to a specific salinity of 23%…laying down streams of cheese brine on nearly 400 miles of state, county and town roads. When used as an anti-icing agent on roads and bridges, the salt crystals in the brine prevent water molecules from bonding together and forming ice.
“It just really buys us some time,” Narveson said. “As the storm hits, we pre-wet the rock salt coming out of the truck spreader with brine so that the salt sticks to the pavement and activates.”
Other than that, it’s a good idea.
Thanks for the link. I did not know about this before.
The amount of of salt is orders of magnitude less from what I understand.
There is also beet juice, from sugar beets, not the red kind – although blood red roads in the winter would have a certain charm.
I get that, but I’m pretty sure undercoat protection exists for these cases, wax in frame holes, etc. that’s something I don’t need and don’t wanna pay for in a state where rust is barely a thing. CO gets plenty of snow in the mountains and metro area (usually), and while we’ve started using brines for roads, we primarily use sand and gravel. There are pristine GEO metros still being daily driven around here and perfect GMT400s still being used as work trucks. Only recently have I started to see some early 00s GM trucks that have some real cancer rust in areas. But there are ~15 GMT800s in my neighborhood still used for daily use and their bodies are rust free.
If I lived in the rust belt I’d probably undercoat everything, do yearly maintenance on it and fix any rust before it pops up and gets worse, at least if that’s even possible to do out there.
Yes because they can just stop treating the icy roads and have the cars crash which isn’t covered under warranty.
… or they could require people to use winter tires in the winter time.
They’d still rust underneath.
Car washes do have under spray for the frame
If that was enough, composite panels would matter even less for the body.
Most of the engines I’ve worked on in the last decade have ended up in a chassis made from extruded and bonded aluminium, and had composite bodywork on top.
The steel brackets rust though. I’m going to have to repaint a few on my 2007 Europa this year.
A friend junked a Land Rover because all the aluminum that lasts forever was attached to steel that rusted super fast in NY salted streets. He imported a 40 year old old truck from Africa in great shape and after 3 years in NY it was junk.
Galvanic corrosion really was extreme between the aluminum and the steel.
Sure just triple the purchase price and the length of the payments.
In Washington state, they use salt pretty much as a last resort, electing to pre-treat roads with calcium chloride or magnesium chloride. Probably as much to extend the lifetime of bridges as the vehicles that go over them.
Snow and ice plan | WSDOT
One of the not-so-great things they do in WA is lay down sand. On the first nice day after an extended stretch of snowy ones, I took a ride on my motorcycle and found quite an accumulation of sand which I found in the middle of an intersection while turning left. Two broken ribs, a broken clutch handle, a scuffed up armored motorcycle coat, a written off helmet and four months later I was back on the bike.
My father had a couple of steel-hulled commercial fishing boats, and they had zinc sacrificial anodes attached to the hull and had to be replaced periodically but greatly reduced the rate of corrosion. I guess it’s the idea behind the use of galvanized steel, but clearly there is room for improvement.
Porsche has been galvanizing their cars since 1975.
They put a 911 on a beach with seawater covering it for a few years as a test, and no corrosion.
I don’t know if that makes a Porsche the perfect winter beater or not. Corrosion is a solved problem, but nobody, even Porsche, thinks it’s a marketable attribute.
With cars lasting longer in most other ways, perhaps it’s time to rethink that.
Planned obsolescence maybe not but over optimized surely. Add inferior materials or subpar manufacturing practices that so often happens with business and finance people cutting corners and breakage galore.
Also replacing parts with cheap Chinese junk that rusts faster doesn’t help
While I angree that engineers don’t intentionally design parts to fail after the warranty, I do think the corporate universe bends somewhat naturally in that direction, through no fault of the engineer.
Parts that fail before the warranty get top priority for redesign, so failures in warranty end up being pretty rare. Conversely, a part that’s too reliable is more likely to end up on some MBA’s list for the next model redesign: “hey, can we reengineer this part to be lighter or cheaper?”
Repeat for decades with each new model and eventually you end up with a large number of parts that fail within kind of a specific timeframe that, yes, starts right after the warranty ends.
The vast majority of parts on a car never fail. That is what people miss. A car is made up of thousands of parts but people focus on the handful that fail instead of the majority that don’t.
That might be because after one part failed the car is no longer available to operate.
Yet in reality cars are lasting longer and longer.
In 2000 the average age of a passenger car was 9.1 years. In 2025 that is 14.5.
Yes, how many parts were there on the Challenger space shuttle?
How many failed?
You have to admit that it had a parts failure ratio that was statistically insignificant.
Something like an O2 sensor on a car failing is a bit less critical and less catastrophic.
The simple fact is that cars are more reliable today than in the past.
Your comments to First Last’s thread here are underated gems.
Mic drop. Great read
Not being in the automotive field, I always assumed the flow went as such.
Higher ups to Bean counters: We found that most people had no problem with our cars before 50k miles. We’ll set our warrenty there for the new model.
Higher ups to Engineers: I need you to make this new car better in every way and cost 5% less.
Repeat for 10 or so generations and now it’s a miracle we have a car that lasts longer than almost any warrenty from 30 years ago
“I need you to make this new car better in every way and cost 5% less. Repeat for 10 or so generations….”
What you described is what actually happens. The result is that now we have cars that are safer, more fuel efficient, more powerful, and larger than in the past – while at the same time lasting longer and like-for-like costing less than cars in the past when accounting for purchasing power and inflation.
1995 Honda Civic DX Sedan: 102 hp / 98 lb-ft / 28 mpg / 0-60 9.3 sec / subcompact car. (No cruise control or power windows). $12,360 ($26,767) in 2026
2026 Civic LX Sedan: 150 hp / 133 lb-ft / 36 mpg / 0-60 8.8 sec / midsize car ($24,695)
Warranty used to be 12 months or 12,000 miles now it’s 10 years 100,000 miles. I think you are wrong.
Aircraft engineer here. I reiterate what he said. The variability between parts that appear identical in dimension can be extreme. the tiny bit of variability in material batches in composition and hardness and heat treat makes it virtually impossible, and that is without taking into account the inherent varibility in fatigue life even for parts from the same batch/lot of material (they call it “scatter” for a reason!).
But. Key characteristics are measured and logged and retained. Small lot SPC techniques predict 99.99+% confidence part conformity. Robust design accounts for minor small slips.I don t agree with your points. (ASQC CQE, FAA DER here.)
I believe that’s why we see so many failed wheel bearings these days. The design margin has been greatly reduced and any shortfall in metallurgy is trouble. In the 60s and 70s I worked on a lot of old cars and never saw a failed wheel bearing.
I haven’t seen a grease fitting on a bearing in this century.
Nor the old standard callout in the maintenance section of the owners manual to repack wheel bearings every 15K miles.
On a Toyota if you buy a rear “wheel bearing” you get an entire hub assembly including everything from the ABS sensor to the wheel studs. Presumably there is a sealed bearing or two in there, but there’s no way to get to them.
Actually if I build a trailer, rear hubs from a Toyota look like the way to go. Simple and cheap.
Dave Larkman obviously doesn’t work for Stellantis. They design their vehicles to fail even during the warranty period.
Given the number of names that has been on the building and the number of organizational tear-ups since the 80s, I’m actually impressed they can put anything out the door.
There is a very thin line between “designing parts to fail when the warranty is over” and “making parts durable enough to outlast the warranty period”.
Sometimes it’s a thin line, sometimes it’s a super-thick line. They don’t know, and they especially don’t do it on purpose.
But if you want a car to last 20 years, you probably want them to spend less than 20 years doing pre-series testing before they sell it to you.
And that’s why I like cars that have been in production for a few years. People that say brand x is failing because they haven’t updated their product are nuts. I have no desire to own a Crown Victoria, but a smaller car that had been in production that long and optimized for fleet operators would be exactly what I wanted.
One of the author’s main points was exactly on this topic. I’ll paraphrase it differently for you.
A part has to survive the warranty period under the most strenuous reasonable conditions. Let’s say it needs to survive up to the 95th percentile of bad operating conditions, otherwise warranty replacement costs will be too much. If you in particular are treating that part in particular just barely better than that 95%ile case, then yes it is likely to fail just after warranty. But you probably aren’t. So the design durability necessary to meet that 95%ile target means yours will last way longer.
And maybe you are near that 95th %ile. That’s only going to be for some parts. Failure conditions are different for different parts, so strenuous for some are very easy for others. There is no possible way that every part, or even most of the parts, of a vehicle can all be subjected to just under the maximum design stresses so that they all fail right after warranty.
If parts are made to make it to warranty under the worst conditions, which they are, then for most users most parts will last way beyond warranty, which they do.
True but the builder also has specs that set an acceptable failure rate so a certain percentage will fail before the warranty is done.
But that rate is really low. If it isn’t really low, it costs them.
Is it possible for every single part to get failure rates to almost zero? Yes. But there is a point of diminishing returns. A car made of entirely 0.00000000001% 10-year failure rate parts would cost tens of millions of dollars and weigh 10 tons.
All engineering is an exercise in compromise, and I think the author of this piece makes a very solid case that the compromises that we live with are generally pretty good.
Or, for a unit with a thousand parts to make it just past warranty then fail, 999 of them will go to recycling in serviceable if not perfect condition.
Great article. This is the reality but there is a group of people that will never believe you. (or me)
I don’t believe you.gif