rattle pistons oil change?

[tig1]

Originally Posted By: PT1
Originally Posted By: tig1
I think piston slap is a design flaw. I for one would not own an engine that hammered every time the engine is started cold. GM has been sued by people all over the US for this problem, and my guess is they regreit ever building them that way.


I have had 2 a 2002 5.3L and a 2006 6.0L...both very annoying and GM refused to do anything short of extending the warranty on the 06 to 100k which did nothing for the noise. Pennzoil 10w30 conventional did the most for noise abatement but the real fix came by getting a Toyota 4Runner after becoming thoroughly disgusted with GM forever. When you spend $100k on vehicles and the manufacturer says "they all do that" you tend to look for a manufacturer who can build an engine that doesn't knock for 5 minutes after you start it. The 6.0L got so progressively bad it would knock for 8 minutes. FWIW, you will never convince me GM cares what happens after you drive off the lot on day one as they fought my warranty claims from the beginning.




I buy American but can't blame you for you choice. A friend sued GM over his Chevy Problem, but lost. He called Jasper engines and they said their rebuilds have solved the problem. It's just not normal for engines to hammer on cold starts.

 

[PT1]

Originally Posted By: tig1
Originally Posted By: PT1
Originally Posted By: tig1
I think piston slap is a design flaw. I for one would not own an engine that hammered every time the engine is started cold. GM has been sued by people all over the US for this problem, and my guess is they regreit ever building them that way.


I have had 2 a 2002 5.3L and a 2006 6.0L...both very annoying and GM refused to do anything short of extending the warranty on the 06 to 100k which did nothing for the noise. Pennzoil 10w30 conventional did the most for noise abatement but the real fix came by getting a Toyota 4Runner after becoming thoroughly disgusted with GM forever. When you spend $100k on vehicles and the manufacturer says "they all do that" you tend to look for a manufacturer who can build an engine that doesn't knock for 5 minutes after you start it. The 6.0L got so progressively bad it would knock for 8 minutes. FWIW, you will never convince me GM cares what happens after you drive off the lot on day one as they fought my warranty claims from the beginning.




I buy American but can't blame you for you choice. A friend sued GM over his Chevy Problem, but lost. He called Jasper engines and they said their rebuilds have solved the problem. It's just not normal for engines to hammer on cold starts.


When GM stopped hand fitting pistons in engines they created this issue. They know it and don't care. So, one by one they are losing valuable long term customers like me. (20GM vehicles) to Toyota or others. Too bad. Now look where they are. They are just not the reputable company they once were.

 

[BuickGN]

Originally Posted By: OVERK1LL
Originally Posted By: BuickGN
Typically it's engines with forged pistons that have cold piston slap.

Forged pistons expand more when hot so cold, the clearances are looser.


The LSx engines notorious for it use hypereutectic pistons FWIW.

The reason is that GM went from hand-fitting the pistons in the bores to bulk boring and bulk pistons. So you end up with some pistons that are, due the the inherent nature of mass manufacture, smaller than average and some bores that, due to the same reason, are larger than average. This creates noise of course. Combined with the almost complete lack of skirt on the LSx pistons and it really is a no-brainer as to why it happens.


I was taking a shot at the LSx motors but the sarcasm didn't come through.

 

[OVERKILL]

Originally Posted By: BuickGN
Originally Posted By: OVERK1LL
Originally Posted By: BuickGN
Typically it's engines with forged pistons that have cold piston slap.

Forged pistons expand more when hot so cold, the clearances are looser.


The LSx engines notorious for it use hypereutectic pistons FWIW.

The reason is that GM went from hand-fitting the pistons in the bores to bulk boring and bulk pistons. So you end up with some pistons that are, due the the inherent nature of mass manufacture, smaller than average and some bores that, due to the same reason, are larger than average. This creates noise of course. Combined with the almost complete lack of skirt on the LSx pistons and it really is a no-brainer as to why it happens.


I was taking a shot at the LSx motors but the sarcasm didn't come through.

No, it didn't