Best and MostReliable Engine

my 22 rst with 5.3 lt has 75k on the clock. no issues so far.

Our 21' has been pretty darn good 5.3 with 40k miles.

Disable auto start/stop with a plug-&-play module, I have a 3.0 diesel and I think it’s one of the best powertrain. However, I don’t have a lot of miles, I put 11,000 miles on 2021 RST diesel Suburban, and now about 10,000 on my 2023 Yukon XL SLT diesel, and had no emissions or engine issues, plus I overall averaged 24.5mpg combined for city/hwy over the total 20,000 miles with both. I am not a mechanic but I think the new auto start/stop feature that automatically turns on every time you start the engine is making it worse for reliability and creates more problems down the road for both gas and diesel engines. But that’s just my thought, I always tried to turn it off every time I started the engine, but now have the harness installed where the system remembers the last setting so I don’t have to turn it off every time.
2021+ does ride a lot better with Independent rear suspension compared to 2015-2020, I had a 2016 Yukon XL 5.3l gas prior and put about 25,000 miles on it without any issues, it didn’t have auto start/stop and I averaged about 17.5mpg overall.

yukon-xl said:

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And this was my 2016 5.3l showing avg over 9,300miles as 16.8mpg before I sold it

Don't forget the transmissions! They're junk now, too!

Either the newest 3.0 Diesel or a 6.2L both w/ a GM ext warranty. Holly makes a AFM/DFM defeat all the way up to 22 now.


They’ll crack on to later models as the geeks have more time on the 23+ vehicles. Either motor paired to a 10SP is butter smooth. There will be problems I guarantee anyone, it’s a mechanical thing no vehicle is immune from.

Offthesheet said:

Hello all, we are considering a big GM SUV and want to know overall which engine is the best one for reliability? I want a suv with room and an engine that will be super reliable so I can sleep at night. I hear a lot about emissions issues and def issues with the diesel or lifter issues with the gas, but is this fixed now?

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Personally, I’d stay away from the diesel due to the belt driven oil pump in the crank case. What could possibly go wrong with that design? Supposedly it sheds tiny bits rubber that potentially blocks oil passages. What was so wrong with shaft/gear driven oil pumps? I guess they are just saving money hoping to get beyond the warranty period.

tom3 said:

I guess we really lucked out with our 2019, maybe. Sales were real slow, got a super deal on the machine on the lot and it was exactly what we were looking for. For me it's like driving a bus but we bought it for a highway machine and we load it up and take off every so often.

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We did the same thing and bought a bus of a vehicle. If you look at my other thread I started I actually got a unicorn of a truck, 2018 Suburban 3500 LT. It has all the bells and whistles but has the HD transmission and the old school 6.0 Vortec which I think is has a near unanimous opinion of being very reliable.
We will be towing with it eventually but right now it’s just the tour bus as we road trip everywhere. 30 days into ownership and 3k miles on the odo. It unfortunately drinks gas a bit more vigorously than the 5.3 and the diesel as my average is about 14mpg commuting and maybe 16-17 on flat highway. 14.5-15mpg going thru VA and WV.

Talking about new with warranty, there’s been some lemons but there’s thousands of 5.3l an 6.2l V8’s out there with over 100k still running strong.

I drove a lot of new 2024 trucks and all ran strong and smooth but none sounded as good as the GM V8’s. I didn’t get a chance to drive the Wagoneer V8 option. The Ford and Toyota 6 cylinder was better than I expected from a normal drive perspective but full throttle left a lot to be desired in terms of performance and sound.

The 10 speed transmissions in Ford, GM and Toyota shifted perfectly with slow acceleration/deceleration, lugging and full throttle. I don’t know how anyone could criticize any of these new 10 speed trucks.