Home » How Parking Under A Tree Can Kill A First-Gen Porsche Boxster

How Parking Under A Tree Can Kill A First-Gen Porsche Boxster

Boxster Roof Tray Drains Topshot
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The original Porsche Boxster is an astonishing amount of car for the money, but it comes with some pitfalls. Everyone knows about the infamous IMS bearing issues, and a few people have found that timing chain guides can get brittle after a few decades, but there’s a less-discussed hidden Achilles heel on the 986 Boxster that can actually brick the car. However, for things to get that bad, a little bit of cleaning needs to be neglected. Let me explain.

The original Boxster is something of a packaging miracle. Porsche had to fit a rear-mid-mounted flat-six engine, two trunks, a functional stainless steel roll bar tied into the chassis at four points, a space-saver spare tire, four four-piston calipers, six speakers, two radiators, four airbags, an entire power convertible top mechanism, space for two passengers, and room for 255-section rear tires into a package roughly the size of today’s BMW Z4 (Oh, except for the 95.2-inch wheelbase, which is shorter than that on a Z4). We’re talking about a tiny-by-modern-standards mid-engined roadster that can swallow two carry-ons, a couple of duffel bags, and just enough camera gear to channel your inner Ansel Adams, all without looking like a poorly-proportioned kit car. Mind-blowing stuff, right?

Vidframe Min Top
Vidframe Min Bottom

Due to fitting so much stuff in a relatively small car, there wasn’t much room left for the immobilizer module, the electronic security computer that does a secret handshake with the engine ECU to mitigate theft by disabling the ignition should an incorrect key be used. In short, it’s the module many Hyundai and Kia owners wish they had, but just like any older computer, the immobilizer module on a Boxster wasn’t exactly small. However, the area under the driver’s seat is free real estate, so Porsche stuffed it there. I gotta admit, that’s a pragmatic move. BMW fills the same area with audio woofers, and numerous other cars have everything from amplifiers to tire changing equipment cached under a seat, so there’s definitely precedent for locating electronic components at the lowest point of a car’s cabin.

Boxster Roof Tray Drain Annotated

Speaking of packaging, every car needs drain holes in recessed externally-accessed compartments, and the Boxster is no exception. Since the convertible roof, once folded, sits in a compartment beneath a hard tonneau cover, that tonneau cover has exposed edges just like a hood or a trunk lid would. Also like many hoods, the hard tonneau has some level of sealing, but it isn’t perfect and rainwater can run down into the convertible top storage compartment beneath the tonneau even with the roof up.

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To manage water ingress, the top storage compartment, pictured above, features a foam trough with drain holes connected to piping that leads down to just ahead of the rear wheel arches. However, Porsche forgot one crucial thing — it didn’t put any mesh on the holes in the trough. As a result, any leaves, dirt, and other debris that slips past the tonneau seals can cover or otherwise clog the drain holes. If you know anything about gravity, you probably know where this is going.

Once those drain holes clog up due to insufficient maintenance, water backs up and runs into the passenger compartment, eventually settling on the floor. Uh-oh, isn’t the sensitive electronic immobilizer module also on the floor? Why, yes it is! Given that most people don’t consider cleaning their cars’ drain holes to be part of regular maintenance, the consequences of leaving out a few grams of mesh are predictably both common and expensive.

How expensive? Well, the last 986 immobilizer replacement I quoted for a customer in a past life had a total retail cost cost north of $2,000 and required programming using a Porsche PIWIS diagnostics and coding system. That’s not exactly equipment everyone has laying around, so lead time on immobilizer module replacement may leave an affected 986 out of operation for weeks.

Oh, and when I say out of operation, I really mean it. There’s a solid chance that a 986 Boxster with a damaged immobilizer module just won’t start. Other symptoms may include windows and a horn with minds of their own, non-functional key fobs, electronic trunk latches on later models that just don’t work, and an inoperable cabriolet top, since all of those functions are tied into the immobilizer module. Christine? Is that you?

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Porsche Boxster Roof Drain Mesh

Porsche, eventually sensing it had made a significant mistake, rectified the lack of drain mesh on the subsequent 987 model from 2009 onwards. In fact, Porsche part number 98756148700 “Water strainer” doesn’t just fit earlier 987 models, it fits the 986 too. Considering that each mesh wedge costs around $10 and only two are needed per car, that’s dirt-cheap insurance against a waterlogged immobilizer module.

Also cheap insurance? Going through the drains periodically using one of those long, flexible trombone cleaner. This one time at band camp, am I right? But for real, these things are cheap and awesome at cleaning drain holes, probably because they’re meant for cleaning spit out of that instrument every teenager used to make racecar noises. On a more expensive note, there are companies offering waterproof immobilizer cases that you seal with silicone, which don’t just guard against clogged drains but also prevent heartbreak due to getting caught top-down in heavy rain.

Img 4982 Cropped

However, don’t let water drainage issues dissuade you — most common 986 Boxster issues can be worked into regular maintenance. That IMS bearing? Do it with the clutch since you’ll be dropping the gearbox anyway. The drain holes? Buy the covers, and work cleaning out leaves and whatnot into a quarterly routine since it’s damn near free. With a little time and effort, you can enjoy one of the last great sports car bargains, a playful mid-engined roadster with outstanding parts support. It writhes and screams and vibrates your fingertips like a sports car should, and when you’re done living north of 4,000 RPM, it settles down and becomes demure, composed, and reassuringly cosseting. The truth is, greatness requires effort. Don’t let the fear of failure stop you from trying.

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(Photo credits: Thomas Hundal, eBay)

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My Goat Ate My Homework
My Goat Ate My Homework
8 months ago

ohhh, this is fun. How about 2 sunroof drains with hoses that go down each A-pillar. BUT over time the hose likes to creep off of the barb from the drip tray eventually draining water right into your A-pillar and eventually wicking up into your headliner and dumping into your carpet.

It was a design error. Due to the different coefficients of thermal expansion the hose would snake its way off 100% of the time. It was just a matter of how long. Rectified with duct tape or a zip tie.

last model Grand Am in case you are wondering.

Urban Runabout
Urban Runabout
8 months ago

Why would anyone park a nicer car like this on the street or under a tree is certifiable.
There’s these things called “Garage” and “Carport” that you should park your car in/under.
At the very least, there are other more portable things called “Car Cover” that you can put over your car when parked overnight.

These are made to keep your car protected so that you don’t wind up with situations like this – or rotted window seals, faded convertible roofs, sunbaked & cracked interiors, frosted-over headlamps, corroded & oxidized chrome/black trim/clearcoat – or just plain dirt & leaves all over your car.

R V
R V
8 months ago
Reply to  Urban Runabout

If you live in Vancouver, you’ll see brand new Aston’s street parked year round.

Scott
Scott
8 months ago
Reply to  R V

Agreed. I live in a nicer bit of LA, and on a single dog walk, I can count on walking past at least 4 or 5 six-figure cars. There’s a Mercedes Benz AMG GT consistently street-parked way down the hill… within a block and a half of a homeless encampment. It’s this most alluring shade of metallic yellow too. I don’t know what they cost, but probably more than a house in some less expensive parts of the country.

Urban Runabout
Urban Runabout
8 months ago
Reply to  Scott

I used to live in a nicer part of West LA too – and encountered the same things.

Then I’d see on NextDoor how someone was always complaining about how the wheels/mirrors/bumpers/lights from their Mercedes/Lexus/BMW was stolen right off their car parked on the street in front of their house or driveway.

This is the same neighborhood where the going real estate trend was converting one’s garage into a Studio/ADU/She-Shed, and the gated section of the driveway into a patio…

Scott
Scott
8 months ago
Reply to  Urban Runabout

Generally, you can’t turn a garage into a living unit/studio/gym/etc… if doing so removes it’s usability as a garage… at least that’s my impression via stories from neighbors who’ve made the attempt and eventually get caught by the city, who will force owners to un-do any unpermitted construction. That doesn’t keep plenty of people from doing so anyway of course.

But yes: many folks w/Lambos, and Mercedes EVs, and that ugly new BMW 7-series, mid-engine Vettes, Porsches of various flavors, etc… never park in their garages whether they’re able to do so or not. So it’s the street for them.

Both of my cars together aren’t worth what it would cost to get a good set of tires and wheels for a new 911, but the Miata is always garaged, and the Volvo’s always in the carport. My personal karma isn’t robust enough for street parking. 😉

Urban Runabout
Urban Runabout
8 months ago
Reply to  Scott

Permitting for ADU’s is relatively easy these days.
And changing a garage from a storage locker to a She-Shed just takes a few cans of paint and some thrifted furniture, if you believe HGTV.

P Hans
P Hans
8 months ago

German product engineering requires the owner to follow the maintenance and use the product within specifications. Japanese engineering is built on how the customer likely actually use or even misuse the product. For a german car to last long you need to follow maintenance schedule exactly or better.

Lockleaf
Lockleaf
8 months ago

Datsun 510s have a windshield cowl drain that uses a rubber hose through the interior under the dashboard to connect the cowl to the side of the car so the water can drain. And there is one on each side. And they clog or break and then leak on your feet. Many a floor board has been destroyed by those drains while the car sat parked under a tree.

Erik Hancock
Erik Hancock
8 months ago

FYI – as a trombonist, I can confirm that the trombone slide snake has many uses cleaning things that aren’t a trombone. Also, it’s not for cleaning spit – that just drains out of a little valve at the bottom of the slide. The snake is for roto-rootering out the gross bacterial-fungal colonization that builds up in the dark, humid confines of the instrument.

DDayJ
DDayJ
8 months ago

Great tip! I’ll be cleaning mine out this weekend.

Another fun Boxster (and I assume Porsche thing in general) I just learned is to check an ABS warning light immediately. I’ve had one on for a few weeks and had to get a decent scanner to read it. I assumed it was a wheel speed sensor or something more serious. Nope. Turns out it was the brake light switch, meaning I had no functioning brake lights. Ugh, thank fully I didn’t drive it much and the part is cheap and easy to replace.

Tim Stoops
Tim Stoops
8 months ago

Great buy! Over the years, my bride and I have owned 2 986s and 2 987s. All purchased used, her favorite was an ‘01 “triple blue” that she drove from 22,000 to 174,000 miles before buying an ‘06. Obviously a daily driver in Florida, we replaced the clutch, AOS and the top once and the rest was routine maintenance. All 4 of our cars had the original IMS, including my track-driven Cayman S. Outstanding cars.

MikeInTheWoods
MikeInTheWoods
8 months ago

You know you are buying a convertible from the right previous owner when they include the trombone cleaning tool and show you exactly where and how to use it on the drain holes in the car you are buying. Nice write up.

Urban Runabout
Urban Runabout
8 months ago
Reply to  MikeInTheWoods

Unless it’s a Mercedes-Benz or Audi A5, where the soft top retracts into the trunk behind the moveable partition. You just never lower the roof when it’s wet, or you’ll cause potential rot/mildew on all that German canvas – and you’ll get moisture in your trunk.

Slow Joe Crow
Slow Joe Crow
8 months ago

I can relate, I killed a Volvo 164E because the ECU for the fuel injection is under the right front seat, and when the floor is rusted out and you drive through a big puddle guess what gets drowned.

Fred Fedurch
Fred Fedurch
8 months ago

The ECU in Audi 4000/Coupe GTs were behind the kick panel ahead of the passenger door. The cable came through a grommet in the firewall and into a plug on the lower front corner of the ECU. The grommet would degrade and start leaking, letting water run down the cable and straight into the ECU via the cable connector/plug junction. The DIY fix (to keep water out of the ECU) was to rotate the ECU 180° on the mounts so the connector was now upper rear corner and the water that did make it in (and it did/will) runs down the cable then drips off at the point the cable routing turns upward.

Widgetsltd
Widgetsltd
8 months ago

Thanks for the tip on the water strainer! I’ve had a Boxster since 2009 but somehow I had never heard of that part. Speaking of leaves and Boxsters: It’s well known that leaves and other road debris can build up in front of the A/C condensers, restricting airflow through the radiators. It’s worthwhile to remove the front bumper fascia every few years to clean that stuff out. My car runs cooler since I did it a couple of years ago. While you’re in there, verify that both radiator fans run at both high and low speeds. On my car, one of the radiator fan resistors had failed (open circuit) and therefore that particular fan would run only when high speed was commanded. That’s an annoying issue in a hot climate such as SoCal.

Anthony Henderson
Anthony Henderson
8 months ago
Reply to  Widgetsltd

“…leaves and other road debris…”, and the first time I cleaned mine out, a well-done bird corpse

IanGTCS
IanGTCS
8 months ago

My mustang gets the cabin air intake drains clogged every year or two. Turn left and I can hear the water splashing on the fan. My arms can just fit into the opening to clean out the drain. Ends up being a good reminder to change the filter then too. I ended up getting a long crevice tool for my vacuum to make it easier. Took the little plugs out of the doors too because they seemed to clog up quickly.

Dudeoutwest
Dudeoutwest
8 months ago

On Boxsters, you also want to make sure that the convertible roof lip fits into the channel on the roof frame. The elastic inside the roof structure is old and the elastic cords can break, including the top one that connects both sides together. If your cords are busted, the roof will overlap the plastic arm, right behind the seat on the outside the car and you may get water in through that if you drive like that.

If your elastic is mucked up, it’s easy to get in there and see them, but replacing the elastic is a complete pain in the ass. I used those little things you put on sheets that keep them from coming off the bed. They have a flat clip on each end with a little tensioning block to adjust them. You basically replace the elastic cord from the factory with these little gizmos, which takes 5 minutes to do instead of an afternoon of trying to resew the elastic inside the cover. They’re like $4 on Amazon and are another bit of kit in the Porsche convertible owners’ arsenal to keep the roof healthy.

Hoonicus
Hoonicus
8 months ago

Nice PSA. I’ve seen several VAG products compromised not only by clogged drains, but also water penetration around CHMSL causing havoc.

Toyota_Twatsicle
Toyota_Twatsicle
8 months ago

On the Lexus Forums the 4th Gen RX has a similar problem. Sunroof drain gets clogged by either leaves or insects, car foot-wells get flooded, and you get a 8K repair bill (or insurance totals it out). Its a catastrophe

Last edited 8 months ago by Toyota_Twatsicle
Mike F.
Mike F.
8 months ago

My 220K mile E90 finally bit the dust last winter, when the sunroof drain clogged and the floor filled up after a series of huge storms. My indie guy managed to get it all cleaned up and dried out, but the electronics were fried. Car would start, but the radio had a mind of its own and other stuff started going haywire. The community radio station ended up benefiting from the donation.

With all of the tree-based crap that falls from the sky here in Sacramento, it’s a wonder there are any first-gen Boxers left.

Rapgomi
Rapgomi
8 months ago
Reply to  Mike F.

I have a Chevy work van that used to have lights on the roof. Water leaked through the light base openings and partially shorted the ECU. Until I figured out what was happening, the radio would turn itself on while it was parked and the power locks would start locking and unlocking until the battery went dead…

Benjamin S Lindstrom
Benjamin S Lindstrom
8 months ago
Reply to  Mike F.

Yup, this is a similar problem with the E60 and E61. There are a whole bunch of modules under the spare in the trunk.

There’s a TSB to relocate them before they get fried when the sunroof drains clog and overflow into the headliner, down the sides of the trim, and into the bottom of the spare wheel well.

Scruffinater
Scruffinater
8 months ago

Miatas (at least NAs and NBs) are famous for collecting water in the horseshoe shaped trough around the base of the convertible top when you let the drain holes on either side get clogged. It makes a rather entertaining water sloshing sound when cornering, which conveniently reminds you to snake the drains before it overflows. My preferred tool is some bicycle brake cable.

S13 Sedan
S13 Sedan
8 months ago
Reply to  Scruffinater

I found that out shortly after I bought a Miata years ago. The first time I went out to the car after a rain, it smelled like pure swamp inside. It turns out that my actual drain tubes were completely clear but the sunglass lens and vintage package of Juicy Friut floating around in the drain trough were blocking things up a bit.

LazyN52
LazyN52
8 months ago

Seem like your licence plate has its numbers at a slight angle, like a good amount of the newly issued plates I’ve been seeing lately.

Good old Ontario, always finding ways to fuck up licence plates.

Mercedes Streeter
Mercedes Streeter
8 months ago
Reply to  LazyN52

Omg, now I can’t unsee that.

IanGTCS
IanGTCS
8 months ago
Reply to  LazyN52

It isn’t like our premiere used to run a sticker company. Oh, wait.

Cryptoenologist
Cryptoenologist
8 months ago

MR2 Spyders have the same drain clog issues but luckily no electronics on the floor. Can still get to the ECU but less likely.

Goof
Goof
8 months ago

Just did my drainage channels on my 2016 Boxster Spyder a few weeks ago, just blasting in air with a compressor to yeet everything out of them. Did it last four years ago, and being a garaged car they were very clean, but still a bit of debris in them from blasting down New England mountain and b-roads over the years.

Taco Shackleford
Taco Shackleford
8 months ago

When I had a Volvo V-50 I would have to clean the sunroof drains at least twice a year, or one day the floor would be wet. My approach was remove the a pillar trim, disconnect the top of the hose from the drain and shoot compressed air through the drain line, reconnect, then run some Krud Kutter through a few times to clean any stuck dirt out of the line. All together 10 minutes of maintenance every 6ish months to not have soggy floors.

Sklooner
Sklooner
8 months ago

Mine had four inches of water in the back this summer- had to pull the carpets and seats, luckyily the CEM was spared- I replaced the hoses and bypassed the tiny little rubber elbows that are the issue, and installed some spiffy new leather seats too

Mercedes Streeter
Mercedes Streeter
8 months ago

Ah, German car ownership. In the VW Passat B5, the transmission control module is under the carpet in the passenger footwell. When your drains are clogged, water can fill up the compartment. The TCM is supposed to be in a waterproof case, but lol.

Clearly, VW thought of water intrusion as a possibility because the compartment has a grommet that allows water to drain. I just leave that grommet open all the time.

Smarts have their TCMs under the driver seat. No drains to worry about, but if you have a convertible and accidentally leave it open in the rain? RIP your transmission.

Collegiate Autodidact
Collegiate Autodidact
8 months ago

Yeah, virtually all the non-wrecked Mk4 VWs I see at the local salvage yards have sunroofs whereas most of the Mk4s I see still on the road don’t have sunroofs; the sunroofs leak when the drains get clogged which will result in the electronics being ruined by water leading to the ingnominous fate of being sent to salvage yards. Also, Mk2 VWs (and I think also Mk1 and Mk3 as well) had the fusebox under the left-side dash directly below a very common source of water leaks due to inadequate sealing in the cowl by the firewall. All of which contributed to So. Many. Electrical. Gremlins. Especially with Mk4 (& later.) That said, I still dearly miss my late and lamented Mk4 Golf TDI and Mk2 Jetta diesel (totalled by a damn rear-ender and a damn red-light-runner, respectively.)

Last edited 8 months ago by Collegiate Autodidact
A. Barth
A. Barth
8 months ago

tl;dr – don’t get electronics wet 🙂

Some family members had an Equinox or a Traverse (I forget) totaled because it was in a flood and water breached the cabin, compromising the electronics that were under the front seat.

Pat Rich
Pat Rich
8 months ago

When I first bought my Land Cruiser it had been sitting outside under a pine tree for some indeterminate amount of time by the PO. Not only did that mean lots of pine tar that is only now 10 years later finally coming off, but it meant that my sunroof drains were clogged with pine needles. I found out when I took it to a car wash and the interior started dripping. Kind of a PITA to get them cleared out, but not having a wet headliner is nice. It also leaked down the b pillar and corroded a few wire junctions that I had to replace. drains…keep em clear.

Last edited 8 months ago by Pat Rich
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