Best and MostReliable Engine

[Offthesheet]

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?

 

[B-train]

By your response, I'm assuming you mean a new one? If that's the case, then I don't really have anything constructive to say. Gas engines seem to have unexpected quality control errors. Diesel has all the emissions crap, but seems to be quite a runner from what people have said here.

However, I am a huge fan of the 6.2L non-AFM engines from 2007-09. I also like the 6.2L LT engines up to the 2020 model year with AFM turned off.

 

[tom3]

If price is not a barrier, I'd go with the diesel at this time. The current troublesome technology just to save a mpg or so with the gas engines is not worth the anxiety. But it would also depend on how long you intend to keep the vehicle. Diesel for the long run.

 

[Antonm]

Nothing new is reliable , gas or diesel, from any manufacturer. It's been a race to the bottom for the cheapest parts and cheapest manufacturing processes for the last decade or so, everything has been outsourced and its all crap. So basically pick your favorite piece of junk. Its like cell phone providers, they all suck, yet we all still have one/ pay for them.

I'm a diesel guy usually (own three diesel trucks currently), but all the new diesels are absolutely crippled with DPF regens and urea injection. And if those totally useless systems go down, the truck will turn itself off and leave you stranded. Not to mention the silly belt driven oil pump that requires transmission removal to get to in the diesels.

If you want new, either plan to get rid of it before its out of warranty or buy the extended warranty because you'll most likely need it (and another car to get you around when the new one is in the shop).
...

 

[buckwild27]

I'm a fan of the 6.2l also with AFM deleted. And to be honest the 5.3l hasn't let me down ever.

 

[Antonm]

I'm a fan of the 6.2l also with AFM deleted. And to be honest the 5.3l hasn't let me down ever.

This is the 2021+ section, there is no AFM on these, its worse, its DFM . With DFM all the cylinders can deactivate and there are 17 different strategies that determine which cylinders turn themselves off when.
And bonus, each vehicle has its own code that needs to be broken to reprogram it, so mail order plug-in tuners just aren't a thing for these.
Deleting the DFM would require really expensive custom tuning for every individual truck, not to mention of course a new cam and 16 new lifters.
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[buckwild27]

This is the 2021+ section, there is no AFM on these, its worse, its DFM . With DFM all the cylinders can deactivate and there are 17 different strategies that determine which cylinders turn themselves off when.
And bonus, each vehicle has its own code that needs to be broken to reprogram it, so mail order plug-in tuners just aren't a thing for these.
Deleting the DFM would require really expensive custom tuning for every individual truck, not to meaniton of course a new cam and 16 new lifters.
...

I did forget to add the years of the 6.2l that I was referring to. But all of them are pre 21+

 

[Doubeleive]

get a nice low mileage 2020 and cross your fingers, I won't be purchasing anything past 2020 myself, whole different ball game
perhaps a future design after the T2's just have to see how it goes.....
even the k2's have thinner metal, thinner paint but seem to be holding up ok otherwise
in any case get a higher trim that has sound proofing from the factory so ltz, denali, escalade, unless you really like to hear road noise

 

[tom3]

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.

 

[umar96]

> I hear a lot about emissions issues and def issues with the diesel

Where did you hear this?

 

[toi]

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

 

[Saltydog]

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

 

[yukon-xl]

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]

 

[yukon-xl]

View attachment 431070

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

 

[steve45]

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

 

[petethepug]

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.

Pulsar LT

Your truck, the way you want it. Make changes on the fly without a tune and without voiding the factory warranty.

www.rangetechnology.com

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.

 

[ClayCollins]

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?

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.

 

[Bigburb3500]

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.

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.

 

[BacDoc]

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.