L92 made it 53,700 miles
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L92 made it 53,700 miles Well, Here we are stranded in Benton, AR. Came up here for my grandmother's funeral. L92 in the Denali has been making the piston slap noise for 2 years now. Got the OK from all the GMC dealers in the Houston area. Got up this morning to go to church and she was tapping loud and with a different tone. Headed down the road maybe 5 miles and she started missing and went into limp mode. Then we heard a noise that sounded like parts bouncing in the combustion chamber. Made it back to the hotel and plugged in the HPT. Misfire code, input shaft speed code,(misfire), and multiple knock detected. Oil splatter on driver's side firewall. Got the extended warranty. Let us see how this goes tomorrow at Everett GMC in Bryant, AR. 
Ford Dealer next door. Maybe a new 5.0 Expedition?????
Ford Dealer next door. Maybe a new 5.0 Expedition?????
Well, Here we are stranded in Benton, AR. Came up here for my grandmother's funeral. L92 in the Denali has been making the piston slap noise for 2 years now. Got the OK from all the GMC dealers in the Houston area. Got up this morning to go to church and she was tapping loud and with a different tone. Headed down the road maybe 5 miles and she started missing and went into limp mode. Then we heard a noise that sounded like parts bouncing in the combustion chamber. Made it back to the hotel and plugged in the HPT. Misfire code, input shaft speed code,(misfire), and multiple knock detected. Oil splatter on driver's side firewall. Got the extended warranty. Let us see how this goes tomorrow at Everett GMC in Bryant, AR.
Ford Dealer next door. Maybe a new 5.0 Expedition?????
Ford Dealer next door. Maybe a new 5.0 Expedition?????
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Last edited by midevil1; Mar 20, 2011 at 10:52 PM.
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Its not that he didn't wanted to get it fixed, GM didn't want to fix it. I worked for a GM dealer so I know exactly what happened between him and the dealer.
To the OP, good luck on getting the truck fixed.
To the OP, good luck on getting the truck fixed.
You're saying your truck came from GM with a Hot cam, Kooks, Vararam, etc? I know some of the parts are GMPP parts, but thats not something you'd just drive off the lot like that with a full blown warranty unless its a special dealership agreement or something.
Either way, good luck.
Either way, good luck.
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Alright guys, Had it towed to GMC dealer this morning. Service writer came out immediately and asked for year and mileage. When I told him, he said they would fix everything and pay for all of my rental car bill. I showed him my warranty agreement with performance parts installed and said they would fix it under regular GM warranty. He said failure was unacceptable for age and mileage.
Other GM dealers kept giving me the piston slap excuse, even know I would tell them that it was a valvetrain noise. I think they were stringing me along until my warranty was up. Engine had other idea's...Time will tell how this turns out. Suppose to call me with what failed.
Other GM dealers kept giving me the piston slap excuse, even know I would tell them that it was a valvetrain noise. I think they were stringing me along until my warranty was up. Engine had other idea's...Time will tell how this turns out. Suppose to call me with what failed.
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I was told by dealer it is for sure in the valvetrain. News too me
.
Wife says she wants mid-60's Nova with LS drivetrain. After the Denali is fixed. It is going to a new home.
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So as of now NO damage to valvetrain 
#5 piston tossed it's entire top ring land. With a bore scope you can actually look at the top ring on the piston. All the marbles I had heard was that piston finally SLAPPING itself TO DEATH. One other piston on driver side started to toss it's ring-land slightly. Passenger side is is totally fine. Cylinder walls for problem piston's aren't that bad either. NO scoring. You can still see cross-hatching. Exhaust valves and exhaust runners show no damage. Face of valve has lots of pits of course.
My dealer here in Houston came and got truck on Flatbed last night and brought it home. They are fixing it, since it was their agreement. After, new motor gonna put truck back too stock and trade it in....
#5 piston tossed it's entire top ring land. With a bore scope you can actually look at the top ring on the piston. All the marbles I had heard was that piston finally SLAPPING itself TO DEATH. One other piston on driver side started to toss it's ring-land slightly. Passenger side is is totally fine. Cylinder walls for problem piston's aren't that bad either. NO scoring. You can still see cross-hatching. Exhaust valves and exhaust runners show no damage. Face of valve has lots of pits of course.My dealer here in Houston came and got truck on Flatbed last night and brought it home. They are fixing it, since it was their agreement. After, new motor gonna put truck back too stock and trade it in....
Hmmm ring land? Did they tune the thing after the cam install? Sounds like detonation issues moreso than piston slap problems to me but its kind of hard to guess without being a part of the teardown. Maybe they had Chuck Cow tune it 