08 suburban 6.0 bottom end tick/knock

[Sobby09]

Hello so I’m coming here because I’m at a loss. So purchased an 08 suburban with the 6.0 had 180k on it. Engine ran smooth no issues back in April. Since then the lifters were replaced pistons/rings and all new gaskets/seals. First the lifters ran beautifully after getting it back for about a week or two then started smoking. Took back to the garage they went over everything they did and then did another oil change. Two weeks later smoking again. After all that took it to a Chevy dealer and they came to the conclusion that the oil rings were shot. So at that point I just had them put new pistons in as well. Didn’t make it home and went into limp mode 16 miles into the drive. Got it home they didn’t hook everything up. Did it myself but something still didn’t seem right. Motor was all but completely rebuilt on both bottom and top end. Took it back with video of what I found and they went back over “everything”. I didn’t mention this was all done under warranty. So the warranty company made them check everything over while the motor was apart. Vehicle still smokes (not nearly as bad) and now has acquired this horrible bottom end tick/knock. Not 2500 miles later. Any help would be appreciated. 

[swathdiver]

On 11/20/2021 at 2:09 PM, Sobby09 said:

Hello so I’m coming here because I’m at a loss. So purchased an 08 suburban with the 6.0 had 180k on it. Engine ran smooth no issues back in April. Since then the lifters were replaced pistons/rings and all new gaskets/seals. First the lifters ran beautifully after getting it back for about a week or two then started smoking. Took back to the garage they went over everything they did and then did another oil change. Two weeks later smoking again. After all that took it to a Chevy dealer and they came to the conclusion that the oil rings were shot. So at that point I just had them put new pistons in as well. Didn’t make it home and went into limp mode 16 miles into the drive. Got it home they didn’t hook everything up. Did it myself but something still didn’t seem right. Motor was all but completely rebuilt on both bottom and top end. Took it back with video of what I found and they went back over “everything”. I didn’t mention this was all done under warranty. So the warranty company made them check everything over while the motor was apart. Vehicle still smokes (not nearly as bad) and now has acquired this horrible bottom end tick/knock. Not 2500 miles later. Any help would be appreciated. 

What kind of smoke Brian and have you determined which cylinder it is coming from?  Have you put a compression gauge on that or any of the other cylinders?

 

It is SOP to replace the lifter trays and VLOM anytime the lifters are replaced on the AFM system.  Did they use OE trays?  Aftermarket trays fail almost immediately but that's an aside and not sure your problems begin with that.

 

When the pistons were out of the block, were the cylinders checked for roundness, measured for size and honed?

[Sobby09]

Thanks for the response. I was told by garage that they put oem trays in when they put new lifters in. When they put new pistons besides me asking they did tell me that they measure and check all the cylinders. Wether they did hone it or not I have no idea. All this work was done by my local Chevy department. Not if Dan of them just by how they responded to most of my questions. I haven’t determined which cylinder or do a compression check yet. Smoke is heavy white from what I could tell. 

[swathdiver]

On 11/22/2021 at 4:09 AM, swathdiver said:

What kind of smoke Brian and have you determined which cylinder it is coming from?  Have you put a compression gauge on that or any of the other cylinders?

 

It is SOP to replace the lifter trays and VLOM anytime the lifters are replaced on the AFM system.  Did they use OE trays?  Aftermarket trays fail almost immediately but that's an aside and not sure your problems begin with that.

 

When the pistons were out of the block, were the cylinders checked for roundness, measured for size and honed?

 

9 hours ago, Sobby09 said:

Thanks for the response. I was told by garage that they put oem trays in when they put new lifters in. When they put new pistons besides me asking they did tell me that they measure and check all the cylinders. Wether they did hone it or not I have no idea. All this work was done by my local Chevy department. Not if Dan of them just by how they responded to most of my questions. I haven’t determined which cylinder or do a compression check yet. Smoke is heavy white from what I could tell. 

 

White smoke is coolant.  Seems like it is getting into the combustion chamber.  Now the question is where is it coming from?  Cracked head?  Head gasket leak?  Throttle body leak?

 

If Chevy did the work, it ought to be under warranty.

[Sobby09]

Garage came back and said it’s piston slap . Which to me does not sound anything like it. No issues before. Reason I replaced the pistons was it was smoking and the rings wore worn. Figured just to replace the pistons as well. 

[swathdiver]

18 hours ago, Sobby09 said:

Garage came back and said it’s piston slap . Which to me does not sound anything like it. No issues before. Reason I replaced the pistons was it was smoking and the rings wore worn. Figured just to replace the pistons as well. 

Could you possibly record a video, post it to youtube and link it here for us to see and listen to?

[Sobby09]

Now since this I have gotten it back from the garage sounding worse yet. Stating that it’s just piston slap and is fine to drive. That it will not cause anymore damage . 

[swathdiver]

5 hours ago, Sobby09 said:

Now since this I have gotten it back from the garage sounding worse yet. Stating that it’s just piston slap and is fine to drive. That it will not cause anymore damage . 

 

Thanks Brian.  Did you happen to pull the torque converter inspection cover and see if the bolts were loose?

 

Did you say in the video that the oil leaking was new?  Have you checked the level?

 

I'm no expert on all LS engine noises so let's get some folks to have a listen and get their input.

 

@doubeleive@Grumpy Bear@Black02Silverado@shakenfake

 

Brian, bump this thread around 10 am or so and more folks will get to see it as well.

[shakenfake]

You got some oil leaks lol

 

Sounds like piston slap to me though

[Black02Silverado]

Piston slap happens first thing on start up and then goes away.  That sounds more like a lifter is bad.  Could have gotten a bad lifter, it happens. But the smoking is an issue.  That shouldn't happen.  Sounds like they did a bad job of installing the pistons.  More than likely they didn't hone the cylinders since it is smoking.  I would take it back and let them know it isn't right and you want it fixed.  Be nice, I know which will be hard to do but more will get done being nice but firm than demanding with an attitude.

[Grumpy Bear]

8 hours ago, swathdiver said:

 

Thanks Brian.  Did you happen to pull the torque converter inspection cover and see if the bolts were loose?

 

Did you say in the video that the oil leaking was new?  Have you checked the level?

 

I'm no expert on all LS engine noises so let's get some folks to have a listen and get their input.

 

@doubeleive@Grumpy Bear@Black02Silverado@shakenfake

 

Brian, bump this thread around 10 am or so and more folks will get to see it as well.

 

 

I'd be guessing and that isn't useful. 

Sorry.

[doubeleive]

here is my take on it, if there is white smoke and lifter/valve tap, this "might" mean there is water getting in.

has the coolant level dropped at all? even a very small leak will cause a problem, even if it is burning it off and not causing a milkshake.

if so what is happening is the coolant is mixing with the oil in a particular cylinder/area and this makes the oil not as efficient in that area and you end up with "noise" in that area. 

again if this is the case you could pull the valve covers off and see where it is happening it will usually present it's self visibly.

you can also look under-inside the oil filler cap (it has a cavity area when you flip it over) and see if there is any white or green snot looking material and/or look down in the filler hole with a flashlight and look for the same snot. some people say a little material there is normal but I have never found this to be the case with a good running engine.

if it is not loosing any coolant at all then yes it could just be a noisy lifter and likely won't cause any immediate damage, my 03 made the same noise on & off for years and drover perfectly fine, I of course did not have warranty on it nor any engine work done.

the bottom line is like mentioned above take it back and say hey this isn't right, be nice usually that gets you nice in return. even if you didn't have to pay out of pocket yourself they got paid and it should be addressed as long as it is still within the warranty period. a simple "it will be fine" is not acceptable in this case.

[CamGTP]

7 hours ago, Black02Silverado said:

Piston slap happens first thing on start up and then goes away. 

Not always. Many engines can have the piston slap stay even after it's warmed up. Pretty common with the GM 3.1 and 3.4 engines. I bought a 2003 Malibu with 88,000 miles for $600 with engine noise and front end damage. I tore the whole top end apart, inspected all the parts, new lifters and threw it back together. Start it up and has the same exact noise it did before. It's all piston slap in that engine even when fully warm. The oil is completely clean too, no metal shine or glitter. I just stopped caring and it's had about 1,000 miles put on it since.

 

For the OP, it's still kinda tough to nail down exactly where it's coming from. It does sound half the speed of the crank though.

Edited December 4, 2021 by CamGTP

[Sobby09]

Okay so I did check the oil. Nothing abnormal. Coolant seems like it hasn’t leaked either. I haven’t pulled the the cover to check the bolts yet. No when I say it got worse it loud enough to hear knocking while driving. Plus seams to have lose of power if you do drive it. Oil leaks are new. The motor was always dry from when we had bought it. It has been 8 months. All the seals and gaskets for motor are new. Honestly only things not replaced internally are oil pump, crank, rods and rockers. Oil pressure at idle is showing less than 20 now also. You hear it all the time cold start warmed up driving. Tomorrow Ill try to take a another video. Thanks to all that have responded. 

[Sobby09]

Heard back from the new gm dealership today. First thing he pointed out was that cylinder 3 had misfired 7384 times! and others but no so much. His master mechanic was running more diagnostics after hours to try and get to the bottom of what is going on with the motor, but had confirmed that there is some major issues going on with it.