General Motors is gearing up to launch an all-new generation of its revered Chevrolet Silverado and GMC Sierra pickup trucks. Among the many updates is what’s under the power barn, as GM is replacing the reportedly infamous L87 6.2-liter V8 and the 5.3-liter L84 with two new engines. A major change with these engines is that there is no physical way to check their oil level, only electronic monitoring is available. As it turns out, General Motors will sell you a Sierra or a Silverado with a V8 that not only allows you to check your own oil, but gives you two ways to do it. The catch is that you have to buy a heavy-duty pickup, and then get it with the largest possible engine.
Last month, General Motors caused a little bit of an upset among pickup truck fans. When announcing the replacements for the aforementioned L87 and the L84 V8s, it was revealed that the new Chevrolet Silverado and GMC Sierra gasoline V8 engines, the 5.7-liter L76 and the 6.6-liter L78, do not have any physical way to check engine oil level. There is no dipstick or any way to actually look at the oil without draining it. Instead, General Motors expects owners to use a digital readout to know how much oil their engine has and when to add more.
Many readers have asked if this same change will be applied to GM’s heavy-duty pickup trucks. At the time, I could not answer, as GM has been relatively quiet about the changes to the heavy-duty lineup’s engines. We don’t have confirmation of what exactly is going on with the Silverado HD’s and Sierra HD’s updated 6.6-liter L8S V8. However, General Motors has confirmed that, when it comes to checking oil, the new Duramax 8.3-liter diesel V8 gives you the best of both worlds.
We Now Know More About The New Gas Truck Engine
Currently, GM’s gas heavy-duty pickups come with the L8T 6.6-liter V8, which makes 401 HP and 464 lb-ft of torque.
For 2027, the HD gas engine becomes the L8S, which carries over much of the small-block architecture as the L8T. This engine features a cast-iron block, aluminum heads, direct injection, a forged steel crankshaft, forged powder-metal connecting rods, and an upgraded compression ratio of 10.8:1. It also doesn’t feature cylinder deactivation or auto start-stop.
Output is mildly upgraded to 412 HP and 472 lb-ft of torque. Assuming no unforeseen quirks, it sounds like this engine should be a reliable workhorse. However, like the GM light-duty range, this V8 also doesn’t have a dipstick, and owners of HD trucks with this engine will depend on a digital readout for oil levels.
Yet, the latest Duramax didn’t get the memo.
A Lump Of Power
If you missed my last story, I’ll bring you up to speed on the monster that is the 8.3-liter Duramax diesel V8:
General Motors says that the new engine, codenamed “Mongoose,” was designed from scratch in-house specifically for the heavy-duty pickup truck market. The 8.3-liter engine sports a compacted graphite iron cylinder block, a forged crankshaft, forged connecting rods, and steel pistons. GM says the engine’s new architecture features an integrated intake, an “advanced combustion system,” and crankshaft isolation for reduced noise and vibration. It also features a compact dual-stage air-to-water charge cooler, a high-efficiency variable-geometry turbocharger, and upgraded engine cooling.
Backing up all of these goodies is an Allison 10L1000 10-speed transmission, an exhaust braking system, and a diesel aftertreatment system that’s supposedly fit for a truck that lives a hard life of towing and hauling. It all adds up to a behemoth 8.3-liter diesel V8 that pumps out 555 horsepower and 1,230 lb-ft of torque. For those of you counting, this readily beats Ford’s best and leaves Ram in the dust.
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General Motors says the new engine is a rather huge deal. The automaker invested $920 million into its Duramax diesel program to enable it to create this behemoth, which will be built in the GM DMAX complex in Brookville, Ohio. In describing the new engine, GM says that “The all-new available diesel is GM’s first clean-sheet HD V8 designed, developed and manufactured in-house for heavy-duty pickup applications.”
So far as I can tell, when these trucks reach customers, they will have the largest diesel engines ever fitted to mass-production pickup trucks in America. The only larger diesels that I could find are housed in heavy machinery or commercial vehicles.
The sheer size of the engine isn’t just for bragging rights, either. In theory, the big lump of diesel won’t be as stressed as its smaller counterparts when pulling the same loads. Of course, GM couldn’t have chosen a worse time to grace the world with the biggest pickup truck diesel, but that wasn’t exactly its fault. This engine’s development has been going on for far longer than the time in which diesel prices have been high.
As more information about the 8.3 Duramax gets out there, we’ve also learned something a bit fascinating. It will have a glorious, yellow oil dipstick.
But there’s more. This engine will also be getting a digital oil level sensor and a readout on its infotainment screen, just like the new gasoline V8s. This is sort of the best of both worlds. For many owners, checking the digital gauge and topping up as needed will be easy enough. However, for those who prefer to “trust, but verify,” the old and trusty physical dipstick is still there.
This also makes sense, considering the hard work that heavy-duty pickup trucks are expected to do. You absolutely need these engines to be running at a correct oil level.
Why The Gas V8 Ditches The Dipstick
But this begs the question: If General Motors was able to give the biggest, baddest diesel a dipstick, why did the gasser V8s lose it? When I asked General Motors about the gas V8s not having dipsticks, it told me:
For the new light-duty 5.7L and 6.6L V8 engines, GM’s decision to move to electronic oil-level monitoring was intended to simplify the ownership experience. The system allows customers to check their engine-oil level from the vehicle cabin through an on-screen readout, without opening the hood or using a traditional dipstick.
Since then, General Motors has expanded on the answers it’s given to the press. Talking with Tim Esterdahl of Pickup Truck + SUV Talk, GM says that another part of the reason for the change was due to the additional hardware hanging from the new engines. The new port fuel injection and valve body made oil dipstick packaging difficult.
The Duramax, on the other hand, is a completely different engine on an all-new architecture.
Of course, how much this actually matters will depend on your perspective. There have been cars without oil dipsticks for a couple of decades now, and most of them have managed to get by just fine! I suspect that, for most people, not having a dipstick won’t be a dealbreaker. It might even be a positive for the kinds of people who don’t like opening up their hoods.
Still, if you’re a devotee of the dipstick and you want a brand-new pickup truck from General Motors, your options get a bit weird. If you absolutely have to get a dipstick, your best choices are now either the TurboMax four or a diesel. If you want a V8 with a dipstick, apparently, you have to get an HD, and equip it with the burly Duramax. Honestly, I still cannot wait to test one of these new big-boy diesels.
Top graphic images: General Motors; Walmart
Dipsticks are checking the oil level AND the condition of the oil as well. Is there gas or coolant in it? Mind you fucking business says GM. Is it getting excessively dirty as the engine ages? Fuck off says GM. There will be no problems allowed with our new engines until 60,001 miles!!! I wonder if the vehicles report back to GM HQ each time you unlatch the hood? Both dipstick and the dash oil level monitor is the only answer.
Oh, longer than that. Even leaving aside two-strokes (which, to be clear, I do not wish to do), the Ford Model T engine doesn’t have one. Instead it has two petcocks, one above the other. Don’t add oil if there’s still enough for it to run out of the lower one, but then add oil until there’s enough for it to run out of the upper one. So much more convenient this way.
My Ram doesn’t have a dipstick, and I don’t care. I change the oil well within the interval, and if it leaks, I’ll have the leak fixed.
I owned my 4Runner for 7 years, and I only checked the dipstick after an oil change. And honestly even then it really wasn’t necessary, I knew how much oil the engine took, and how much I put in. It didn’t burn any, and didn’t leak any, so no reason to check between changes.
I do think the GM reasoning of “packaging” is nonsense. I remember checking 4-foot-long dipsticks on GM vans when I was a kid, if they can figure out that routing, they can figure out a pickup truck.
I haven’t used a dipstick in like 10 years and it doesn’t bother me. You can buy dipsticks for my cars, but I don’t have $30 worth of care in me to do it. At oil change time I suck 8 liters out, I pour 8 liters in, and I’m done. If it’s the level’s high or low it’ll let me know.
You got an emergency mid-suck, got hit on the head with a brick, got distracted, got abducted by aliens, got yelled at by your mother in law. You’re back to your car the next day, week, month, or year:
Digital systems are all dandy for monitoring. They require up to several minutes of the engine running to show anything at all.
Ideally, you need both. Digital for monitoring, stick for checking.
I have a life threatening medical emergency mid-suck. I am airlifted to the nearest hospital.
After the surgery, I wake up in the hospital bed. I realize I have no idea how much oil I removed. I sit up, shake my fist at the sky, and proclaim “I SHOULD HAVE SPENT THAT $30! WHY. WHY. WHYYYYYYYY.” Tears of regret stream down my face. My remaining days of recovery are tormented by this thought.
I return home. My oil extractor is still sitting there. The brown only goes up to the 6 liter marking. A feeling of calm washes over me. I realize I never needed the dipstick. I get back to suckin’.
Or maybe just pull the drain plug if you’re worried you didn’t remove all the oil?