[JMac151.155]

I saw another thread from a year ago with similar information, but none of it confirmed the only thing that makes any sense to me regarding what happened with my Yukon 6.2. Its 2 years old with around 80K miles, and the motor blew (it was rod knocking, that is as specific as the service center got with me so far). The tech told me this is actually not unheard of for the Yukon 6.2, which kinda blew my mind since I know the LT4 in the ZL1 is well known for being ridiculously robust, handling 1K+ hp with no bottom end reinforcements / upgrades needed. My ZL1 is on the conservative side of tuning, making a meager 840hp at the crank, and it is a happy camper no matter how hard I push it. My Yukon is still under warranty, so all good there, but now I am just curious AF, and wondering if I should just expect the new motor to do the same down the road?

The other threat I read through basically stated the differences between the two motors (apart from the obvious boosted vs NA) are minor, nothing huge, so that leads me to one logical conclusion = weight.

My M6 ZL1 weighs one turkey dinner shy of 4K lbs, my Yukon weights a whole ton more. Its fair that would add a butt load of stress to the motor, but is this really something that makes it 'reasonable' for that motor to go out in less than 100K miles?

[dfxrte]

does the yukon have the lt1? the differences between the two motors are certainly not minor on the micro scale. macro scale yes they are both small block v8's

[Gunkk]

LT4 vs LT1: different pistons, different rods, different crank, and a whole bunch of other stuff. Also made by different folks in a different plant.

[Mark114]

I believe the Yukon has an L87 which is very similar to the LT1.

[Revalot]

It's as simple as DOD/AFM. If it's in there it's trash, take it out.

[KingLT1]

Depending on the year the Yukon has a L86 or L87 which is similar to the LT1 just a different intake manifold. AFM/DOD lifter failures are somewhat common. Spun bearings also happen but not very common. How often did you change the oil? Did you change the oil yourself or take it somewhere that uses brand X oil by the drum?

[m6-lt1]

Originally Posted by KingLT1

Depending on the year the Yukon has a L86 or L87 which is similar to the LT1 just a different intake manifold. AFM/DOD lifter failures are somewhat common. Spun bearings also happen but not very common. How often did you change the oil? Did you change the oil yourself or take it somewhere that uses brand X oil by the drum?

This. Op did you go by the oil change intervals Chevy suggested? A lot of GM trucks have been blowing up with low mileage the last few years and my theory is the oil change intervals that Chevy suggests are too lenient. Add that too folks getting their oil changed a bit after the light goes on and that equals disaster. The average truck owner is less likely to change their oil early versus the average Camaro/Corvette owner.

[JMac151.155]

Originally Posted by m6-lt1

This. Op did you go by the oil change intervals Chevy suggested? A lot of GM trucks have been blowing up with low mileage the last few years and my theory is the oil change intervals that Chevy suggests are too lenient. Add that too folks getting their oil changed a bit after the light goes on and that equals disaster. The average truck owner is less likely to change their oil early versus the average Camaro/Corvette owner.

Oh crap I didn't know the internals were as different as this, thanks for all the info guys, I just figured the LT4 was a blown LT1, but I am a noob at this and have a ton to learn. We did oil at GM suggested intervals, always at the GM service center. Those intervals were 5K, i might just do the oil/ filter myself at, what, 3K? So when tbey drop the new motor in, aside from more frequent oil changes, are there other things I can do to help avoid this 2 years down the road?

[Stephen12ZL1]

I have had similar experience with my '23 Suburban 6.2 which started knocking at 4200 miles which required a new engine. The replacement 6.2 has a lifter tick which I am ignoring for the moment. I personally changed the oil in the Suburban at 500 miles and at 3000 miles. My VIN is in the sequence of the worst production run of 6.2 and was slated for a replacement 6.2 even if it hadn't started knocking. On the other hand...the LT4 6.2 has been perfect and hasn't missed a beat with 7500 very hard track miles. I always change the oil frequently and use the correct PF64 oil filter. The two engines are both 6.2L displacement but their internals and parts used are definitely a notch above in the LT4. You also get an engine plaque with the name of the engine builder proudly displayed! Kimberly Jackson did a fine job with my LT4.

[Camfab]

This is ridiculous, it’s not like this is a new motor, no excuse anyway. I’m not sure I’ll ever buy another GM product. These vehicles should be absolutely reliable, in the world of perf per cu/in they are so underpowered. How many millions of vehicles do you have to produce to get your s$$t together.The Chinese are going to own this country soon enough, as Americans will buy some Chinese knockoff for a third the price and twice the reliability. I’m sorry we are our own worst enemy.
As an fyi, I go out of my way to buy American products, to support American jobs with every purchase I make. I buy factory parts from my local dealer even though it costs more, just to support them. I listen to non SAAVY people talking to dealership people and they just hose them. Mind you this happens at every dealer. Frankly I’m over doing my part each and every day spending my hard earned (physically earned) dollars to support these companies and they just can’t make a quality product.
Ok I’m done with my rant. Happy New Year…

[JMac151.155]

Originally Posted by Stephen12ZL1

I have had similar experience with my '23 Suburban 6.2 which started knocking at 4200 miles which required a new engine. The replacement 6.2 has a lifter tick which I am ignoring for the moment. I personally changed the oil in the Suburban at 500 miles and at 3000 miles. My VIN is in the sequence of the worst production run of 6.2 and was slated for a replacement 6.2 even if it hadn't started knocking. On the other hand...the LT4 6.2 has been perfect and hasn't missed a beat with 7500 very hard track miles. I always change the oil frequently and use the correct PF64 oil filter. The two engines are both 6.2L displacement but their internals and parts used are definitely a notch above in the LT4. You also get an engine plaque with the name of the engine builder proudly displayed! Kimberly Jackson did a fine job with my LT4.

Yep that sounds familiar to my experience. I think I am just going to be an oil nazi once the service center finishes swapping the new motor into the Yukon, my ZL1 lets me know about anything it doesnt like so that one is easy to stay on top of, not so much the Yukon...

Yukon = I have no motor oil, im sure it will be fine
ZL1 = Boss, there is a scary cloud over there, just wanted to make sure you knew about it, ok?