2009 Yukon Denali 6.2 L9H Engine Replacement

[KraftMatic87]

Hey everyone, I bought a 2009 Yukon Denali XL a month ago with 143k miles. It has the L9H 6.2 that did not have AFM / DOD from the factory which is why I was so excited about this truck. Unfortunately for me the pre-purchase inspection I had done for the vehicle somehow missed many thousands of dollars in repairs that were needed, such as repairing an oil pan leak, engine oil cooler and potential rear main seal leak. All that plus a CV axle! I’m trying to see if I can salvage the situation. After a few days of owning the truck I determined on my own it had an exhaust leak on the drivers side manifold. Replaced that and then I heard a knocking noise near the oil pan. I’m afraid I bought a truck with a motor that’s on its way to self-destructing.

After finding that rod knock I took the truck to several shops that told me it is indeed time for a rebuilt or replacement engine. In addition to that I have a leaking oil pan and trans cooler lines, and a broken CV axle on drivers side that needs replacing. I have attached two videos of the noise at idle. This is after the engine has gotten to idling temp.

Here is a more thorough inspection report I had done AFTER I bought the truck.

https://shop.tekmetric.com/inspection/W1ITrcRe8c1o1Zkx7uuIxQDwqrd76pPA2XVCsstIorw

Trying to see if I can even afford to keep this truck after an engine rebuild. I have kids and this thing was supposed to be our weekend travel vehicle for road trips up to the mountains. Now I’m afraid to even drive it around town to pick up kids and groceries.

I’m looking to see if anyone can help recommend a good shop in the Denver, CO area who might be able to do a rebuild / cam swap. So far my best quote came from a shop in Goodland, Kansas that is 3 hrs from my house.

I love this truck and it drives great (for now) but this engine definitely sounds like a ticking time bomb. Looking for any guidance on how I should move forward or if I should just quit while I’m ahead and sell for a loss.

Thanks for the suggestions!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

I cannot personally help you with your question; however, other members on this Forum that have torn this motor apart and are very familiar with it will chime in.

 

[mikeyss]

My 09 Tahoe with the same L9H as yours made that noise too. Mine ended up being a valve seat coming loose out of the head. The valve seat eventually broke in half and made its way into a piston and destroyed it. I wouldn't be so sure you have a rod nock, but you should get a good diagnosis of it. If your head is doing what mine did, you're looking at 1k or less in repairs. If yours fails like mine did, it's gonna cost an engine. I'll post a video of what mine sounded like before it blew up

 

[Fless]

Might be a good time for an inspection camera.

 

[KraftMatic87]

My 09 Tahoe with the same L9H as yours made that noise too. Mine ended up being a valve seat coming loose out of the head. The valve seat eventually broke in half and made its way into a piston and destroyed it. I wouldn't be so sure you have a rod nock, but you should get a good diagnosis of it. If your head is doing what mine did, you're looking at 1k or less in repairs. If yours fails like mine did, it's gonna cost an engine. I'll post a video of what mine sounded like before it blew up

Thanks for the response. I figured I am on borrowed time. I am trying my best to not drive it right now until I definitively know what’s going on. I have had three different shops say I need a new engine but no one wants to replace lifters or anything they just want to drop a crate motor in. I’m taking it to one more shop next week and hoping I can get more clarity on how I can save this engine.

 

[KraftMatic87]

My 09 Tahoe with the same L9H as yours made that noise too. Mine ended up being a valve seat coming loose out of the head. The valve seat eventually broke in half and made its way into a piston and destroyed it. I wouldn't be so sure you have a rod nock, but you should get a good diagnosis of it. If your head is doing what mine did, you're looking at 1k or less in repairs. If yours fails like mine did, it's gonna cost an engine. I'll post a video of what mine sounded like before it blew up

And yes post that video of what your engine sounded like before it dropped the valve. I might have to drive this thing to a shop that’s 2-3 hrs from my house to do the rebuild so I’m trying to keep it parked until then.

 

[mikeyss]

I have more if you can't hear it well enough.

 

[KraftMatic87]

That sounds pretty much identical to what I’m hearing right now. I’m definitely afraid to drive this thing at all. Hoping to get some more answers next week I spent three days calling shops last week trying to get rebuild quotes but if I destroy my motor before then I’m screwed and can’t afford a crate motor.

 

[mikeyss]

Kit Performance built my new L9H and he also did a DOD delete on my 09 G8 GT, maybe he can help you out. He's in Erie though, it may be further away from Denver than you'd like to drive it.
kit-performance.com

 

[mikeyss]

Does your head have an 823 casting? That's what mine had.

 

[KraftMatic87]

Kit Performance built my new L9H and he also did a DOD delete on my 09 G8 GT, maybe he can help you out. He's in Erie though, it may be further away from Denver than you'd like to drive it.
kit-performance.com

I live just 15 miles from Erie. I called Kit Performance last week and they said they only rebuild Subarus now. Do you know of anyplace else? I live in Thornton and the only places in Colorado I got reasonable quotes from were down in Colorado Springs which I think I could also drive to and make it as long as I go slow and don’t drive it until then.

 

[mikeyss]

I live just 15 miles from Erie. I called Kit Performance last week and they said they only rebuild Subarus now. Do you know of anyplace else? I live in Thornton and the only places in Colorado I got reasonable quotes from were down in Colorado Springs which I think I could also drive to and make it as long as I go slow and don’t drive it until then.

I know the owner of Kit, I will ask him for recommendations. I was not aware that they changed to just Subies

 

[KraftMatic87]

I know the owner of Kit, I will ask him for recommendations. I was not aware that they changed to just Subies

Yeah I talked to someone when I called Kit and she said they used to do other make and models but now exclusively do Subarus. Just my friggin luck they were probably the best option close to me for a rebuild.

If you can get any recommendations for me in the north Denver metro that would be most appreciated. My most reasonable quotes were from Kansas and Colorado Springs and having to drive a few hours away with the engine in this state makes me a bit nervous.

 

[swathdiver]

Sounds the same as Mike's.

Lawrence Tolman from Powernation TV has a shop in your area now, Colorado Springs.

Lawrence LT Tolman

I'm LT, and I love to build fast trucks and cars. On my channel, I show you every step along the way, whether its fabrication and welding, wiring, engine swap tips, mechanical repair and more. I try to focus on high performance upgrades, so a lot of the projects I do revolve around adding...

www.youtube.com

LT knows LS motors forwards and backwards.

 

[Fless]

You're thinking worst-case. What if it's just valve work? Why not get an actual diagnosis locally before heading down the rebuild rabbit hole?

 

[KraftMatic87]

Sounds the same as Mike's.

Lawrence Tolman from Powernation TV has a shop in your area now, Colorado Springs.

Lawrence LT Tolman

I'm LT, and I love to build fast trucks and cars. On my channel, I show you every step along the way, whether its fabrication and welding, wiring, engine swap tips, mechanical repair and more. I try to focus on high performance upgrades, so a lot of the projects I do revolve around adding...

www.youtube.com

LT knows LS motors forwards and backwards.

Thanks I’ll try giving them a call next week.

 

[KraftMatic87]

You're thinking worst-case. What if it's just valve work? Why not get an actual diagnosis locally before heading down the rebuild rabbit hole?

I have had three separate mechanics tell me that my engine needs to be either rebuilt or replaced. That is the only reason I’m making the worst case assumption. I’m taking it to one more shop next week to get a 4th opinion before I actually commit to a rebuild. Here are two of the inspection reports I’ve gotten:

https://atxt.me/8HoAI

https://shop.tekmetric.com/inspection/W1ITrcRe8c1o1Zkx7uuIxQDwqrd76pPA2XVCsstIorw

What I’m most concerned about is the place that did my pre-purchase inspection didn’t flag any of this stuff. They sent me this report here that said everything was fine except brake pads:

https://www.shopbosspro.com/getstatusdvionly.php?ro=19180&shopid=19479&typ=dvi

I’m afraid that I’ve been sold a nice looking lemon and I’m just trying to see if I can afford to get the truck roadworthy or not. The expert opinions I’ve gotten so far are not very positive. If I just needed valve work I’d be willing to invest but no mechanic has told me that’s the problem.

 

[swathdiver]

Thanks I’ll try giving them a call next week.

Keep us posted. Even if you have to have it towed to his shop, he'll do proper diagnostics before tearing into it.

 

[KraftMatic87]

Keep us posted. Even if you have to have it towed to his shop, he'll do proper diagnostics before tearing into it.

I could probably drive it there and it would make it. I’m just really bummed I’m in this situation so quickly after buying this thing. The past few weeks have been super tough.

 

[B-train]

I'd say change the oil and put in 15w-40 to drive down, and keep the rpms low and engine load low. Denver to CO springs isn't too bad of a drive if I remember correctly. It may make it.

Or put 20w-50 in it and trade it.........I'm not really serious, but it could be an option. I had an acquaintance 20 years ago that put 80w-90 in an old camaro to mask the rod knock when he got rid of it. I could never do that to a person........maybe a shady dealership though.

I did trade in a 2009 Denali because all of a sudden it started drinking oil on a road trip. It was a beautiful black XL. But, I was tired of the piston slap that never went away and dropped it like a bad habit for a pristine 2017 Denali. I don't feal bad because the salesman said it would go to auction because it had 165k. Somebody got a nice truck for pennies I'm sure and put a motor in it.