2009 Yukon Denali 6.2 L9H Engine Replacement

[petethepug]

Thanks for posting up a few pics of the heart transplant. You’re fortunate to have found another L9H to exchange. Right now they’re as popular as AirPods but just slightly more expensive and hard to find

You just reset the change motor indicator back to 0 and good for a minimum of another 150k clicks but likely 200to 250k.

 

[Actifenpleinair]

Today was the day I finally got to pick up my Denali! The hour and a half drive back home was very smooth, with no issues at all. I definitely can tell the difference with the Jasper reman, and I think the transmission shifts much more smoothly with the new torque converter as well. The truck runs much quieter, and I’m not hearing the metallic piston slap that I was hearing under throttle with my original engine.

We don’t know for certain what was making the knocking noise at idle (might have been valve train as some have said), but after getting a glimpse of my old leaky core I’m glad I have a fresh L9H. Might have had something to do with my rear main seal puking oil!

View attachment 404855

View attachment 404858

Here’s a list of what we had replaced:

• Remanufactured Jasper 6.2 L9H
• Water pump
• Replaced all belts
• Radiator hoses
• Fuel pump
• NAPA Thermostat / radiator cap
• Oil / fuel and air filters
• PCV Valve
• Distributor cap
• Plug wires and spark plugs
• Remanufactured GM Torque converter
• Transmission cooler lines
• Transmission filter / fluid change
• Flex plate bolts
• Engine mounts
• Upper and lower ball joints
• CV axles
• Rack & pinion assembly
• New OEM Hood

I’m real happy we were able to get this truck back on the road. It was great to meet LT and talk for a good half hour before I hit the road. Thanks to everyone on this thread who provided guidance and input. I know I’ll be back with more questions because I have a laundry list of other fixes I’ll taking on myself soon!

View attachment 404856

View attachment 404857

Looking at the list of things they replaced in an earlier one on the original estimate, I noticed a distributor cap? Was not aware 6.2s had those.
Also quote was for 6 qts full synthetic oil, is that what was used for break-in?
I know it's a little nitpicky, but it caught my eye.
Great write up and interesting story about in the shop issues with damage. I had a company car in the shop for a rear end collision in the early 90s. While they were welding it up on the last day, the car caught fire, caught their shop on fire, and then ended up being totaled. I left the company before it was finally resolved. Thanks for Reviving that memory! Lou

 

[KraftMatic87]

WELP! 7 months later we have our first major issue with the Jasper engine. I started her up this morning and noticed it took longer than usual to crank. Once it started it was running very rough. Check engine light and Stabilitrak light was on as well. Plugged in my scanner and came up with a P0303 - Cylinder 3 misfire. Turned it off after a minute or two.

She’s being towed down to Courtesy Automotive down in Colorado Springs. Hoping they can figure it out and I can pick it up in a week or two. We do a lot of trips up to the mountains and I’m just glad this didn’t happen while we were in a remote area.

That noise sounds awful. I'm guessing something valve related. Hoping for the best and preparing for the worst! At least I’m still under warranty for the engine.

 

[donjetman]

Doesn't sone good, bummer.

 

[Geotrash]

WELP! 7 months later we have our first major issue with the Jasper engine. I started her up this morning and noticed it took longer than usual to crank. Once it started it was running very rough. Plugged in my scanner and came up with a P0303 - Cylinder 3 misfire. Turned it off after a minute or two.

She’s being towed down to Courtesy Automotive down in Colorado Springs. Hoping they can figure it out and I can pick it up in a week or two. We do a lot of trips up to the mountains and I’m just glad this didn’t happen while we were in a remote area.

That noise sounds awful. Hoping for the best and preparing for the worst! At least I’m still under warranty for the engine.

View attachment 422666

Well, shit. Thank goodness it has a warranty. I don't recall - did you replace the engine with one that still has AFM?

 

[KraftMatic87]

Well, shit. Thank goodness it has a warranty. I don't recall - did you replace the engine with one that still has AFM?

My original engine and this one did not have AFM. The L9H does have VVT. When I watch this video I can almost hear a similar valve train noise that my original engine was making. The engine we replaced didn’t sound great but it never misfired. This certainly sounds much worse. So bummed but again glad it’s under warranty.

I’m waiting to give my wife the news when she gets home from work AND SHE AINT GONNA BE HAPPY. I just replaced the spark plugs on her 2013 Highlander two months ago because it had a cylinder 6 misfire. Fixed that issue and now here we are with the Denali. LORD HAVE MERCY when it rains it sh*ts lol

 

[Geotrash]

My original engine and this one did not have AFM. The L9H does have VVT. When I watch this video I can almost hear a similar valve train noise that my original engine was making. The engine we replaced didn’t sound great but it never misfired. This certainly sounds much worse. So bummed but again glad it’s under warranty.

I’m waiting to give my wife the news when she gets home from work AND SHE AINT GONNA BE HAPPY. I just replaced the spark plugs on her 2013 Highlander two months ago because it had a cylinder 6 misfire. Fixed that issue and now here we are with the Denali. LORD HAVE MERCY when it rains it sh*ts lol

That's right. Thanks for the reminder. Yeah, that definitely sounds cam related.

 

[Tonyrodz]

My original engine and this one did not have AFM. The L9H does have VVT. When I watch this video I can almost hear a similar valve train noise that my original engine was making. The engine we replaced didn’t sound great but it never misfired. This certainly sounds much worse. So bummed but again glad it’s under warranty.

I’m waiting to give my wife the news when she gets home from work AND SHE AINT GONNA BE HAPPY. I just replaced the spark plugs on her 2013 Highlander two months ago because it had a cylinder 6 misfire. Fixed that issue and now here we are with the Denali. LORD HAVE MERCY when it rains it sh*ts lol

Is labor covered under the warranty also?

 

[KraftMatic87]

Is labor covered under the warranty also?

Yes! Labor and parts are covered, only replacement fluids are not covered per Jaspers repair warranty. I can live with that.

I noticed a small coolant leak on the valve cover before I shipped it down to the shop. The coolant was tinged black so I’m guessing somewhere there is oil / coolant mixing where it’s not supposed to be. You can tell from the discoloration on the exhaust manifold where the coolant has been leaking from. When I checked the oil it was dark and brownish colored which is definitely not good. I’m hoping it’s not the milkshake of death.

 

[adventurenali92]

WOW!!! What a roller coaster ride! I just read through your whole thread! Sounded like you had got the truck pretty dialed in with a lot of high mileage maintenance being hammered out with the engine work and it would have been solid for quite a while. She’s a pretty looking truck for sure! Hopefully the shop that did all the work figures out what’s wrong and fixes it up for you! Hate to see these things broken down! I’m a Denali Xl guy myself and I use my 2006 for all the same reasons you do except I live in the mountains. Rarely have my sisters kids in it these days now that they’re in Tennessee and not California, but when they do ride in it they absolutely love the room and big comfy seats. Currently on a mammoth lakes/Utah road trip for snowboarding. I’d be pretty damn bummed if mine were doing what yours is. Hopefully it gets sorted out soon! Hopefully we see you a round a lot after the fixes so we can help you learn things about the truck cuz we love sharing knowledge and helping others fix them! I’ve learned so much from these guys here and it’s why I’ve kept my Denali for so long cuz I know I can work on it, and if there’s something I don’t know how to fix I can figure it out from the collective base of knowledge here.

 

[j91z28d1]

man that's rough. Hopefully all goes well for you.

 

[mikeyss]

It almost sounds like a valve spring broke, which would cause a misfire if the valve isn't opening. I hope it isn't anything too major.

 

[wjburken]

It almost sounds like a valve spring broke, which would cause a misfire if the valve isn't opening. I hope it isn't anything too major.

I agree. When we lost a valve spring in our 2007 6.2, it sounded very similar.

 

[petethepug]

Chocolate milkshake of death. LOL

Had that happen on three short block reman Ford I-6 200 cid motors in a row in the 90’s. Pulled out one, build up other short block, swap back in, 3 flipping times on my ‘66 Mustang.

I feel your pain

 

[KraftMatic87]

WOW!!! What a roller coaster ride! I just read through your whole thread! Sounded like you had got the truck pretty dialed in with a lot of high mileage maintenance being hammered out with the engine work and it would have been solid for quite a while. She’s a pretty looking truck for sure! Hopefully the shop that did all the work figures out what’s wrong and fixes it up for you! Hate to see these things broken down! I’m a Denali Xl guy myself and I use my 2006 for all the same reasons you do except I live in the mountains. Rarely have my sisters kids in it these days now that they’re in Tennessee and not California, but when they do ride in it they absolutely love the room and big comfy seats. Currently on a mammoth lakes/Utah road trip for snowboarding. I’d be pretty damn bummed if mine were doing what yours is. Hopefully it gets sorted out soon! Hopefully we see you a round a lot after the fixes so we can help you learn things about the truck cuz we love sharing knowledge and helping others fix them! I’ve learned so much from these guys here and it’s why I’ve kept my Denali for so long cuz I know I can work on it, and if there’s something I don’t know how to fix I can figure it out from the collective base of knowledge here.

I was originally looking for a Gmt800 but really loved the look and interiors of the Gmt900s. I thought if I could have a Gmt900 without AFM that would be my sweet spot, and when this truck is running good it’s really hard to imagine wanting to drive anything else. The 6.2 w/o AFM + 6l80 is peak GM truck performance IMO. Unfortunately now I’m debating how much I trust the Jasper product that was installed 7 months ago.

Just looking forward to getting her back on the road.

 

[adventurenali92]

I was originally looking for a Gmt800 but really loved the look and interiors of the Gmt900s. I thought if I could have a Gmt900 without AFM that would be my sweet spot, and when this truck is running good it’s really hard to imagine wanting to drive anything else. The 6.2 w/o AFM + 6l80 is peak GM truck performance IMO. Unfortunately now I’m debating how much I trust the Jasper product that was installed 7 months ago.

Just looking forward to getting her back on the road.

Yeah….. I love my 800….. my seats are so dang comfy on long drives. lol.

The 6.2 is a beast of a motor! I wish my 6.0 was mated to a 6L80 instead of the garbage 4L65 I have lol. But hopefully it’ll get sorted out and you can keep enjoying that 6.2!

 

[KraftMatic87]

Just heard back from the shop. They confirmed with a borescope that cylinder 3 and 7 are dead, and both pistons damaged. Jasper has approved the warranty claim and I’ll have a new engine installed by the end of next week.

Jasper will disassemble the engine themselves and let me and the shop know what actually happened. I will owe $0 for the entire replacement which is a plus. Hoping we have better luck with this next long block.

 

[petethepug]

You owe a grand total of … nuthing, nada, nunca. While we’re doing the entire job for free again would you be interested in upgrading to ARP exhaust studs, an upgraded billet torque converter or polished / aluminum valve covers?

 

[KraftMatic87]

You owe a grand total of … nuthing, nada, nunca. While we’re doing the entire job for free again would you be interested in upgrading to ARP exhaust studs, an upgraded billet torque converter or polished / aluminum valve covers?

Luckily it already has new valve covers and an upgraded GM torque converter was installed during the last engine replacement I’m still recovering from that work that was done last summer so I’m going to politely decline any additional upgrades at this time

 

[petethepug]

Underbody detail and protective coating for a low discount price?

Seriously though, I’m really stoked you positioned yourself so well in having all the work done. It’s mechanical, crap happens and installing the new motor by the same shop will be a breeze with all the bolts are already broken loose.