GM Piston Slap website - Carbon buildup

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schube1255

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Here is a link to the Chevy Piston slap website that claims the noise is a maanufacturer defect in late 90s gm engines.


http://www.pistonslap.com/index.html

-------GM Carbon buildup removal------

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raptorforme93

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Does seafoam really work as much magic as everyone claims? I want to do it to my hoe this week and I hope that it helps. Will it remove a lot of the carbon buildup in the intake ane everything?
 

ezdaar

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yess. it made dramatic improvement to idle quality and performance on my 2000 5.7 denali when I had it.
Took 3 cans over 5 hours to get it to stop smoking and see the biggest improvement.
 
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schube1255

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I used A whole can, dump in style in the gas, and one whole spray 18 oz. can into the throttle body and it did nothing - not a puuff of smoke - no ease of tap sound - but my engine did seem to run tighter.
 

gpracer1

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I didnt record when I did my truck, but here is my vette.
First pic is of the Hoe intake after seafoam while replacing injectors.
Second is vid of my vette starting with seafoam in it (after sitting 30 min). What you dont see is when I drive it :shocked:

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gpracer1
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07Burb

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So basically pouring Seafoam directly into the top end with the motor running will clean the top end and stop the piston slap issue? Do I understand that right?
 

gpracer1

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"Piston slap" usually describes pistons slapping the sides of the cylinders.

I would call this carbon knock, when the carbon builds up on the top of the piston and head, and the piston--> carbon <--head all touch ever so slightly causing noise.

When I worked for Mazda, the 929 had a recall on this. I tore down one of the first engines in 93-94.
 

Trippers99hoe

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"Piston slap" usually describes pistons slapping the sides of the cylinders.

I would call this carbon knock, when the carbon builds up on the top of the piston and head, and the piston--> carbon <--head all touch ever so slightly causing noise.

When I worked for Mazda, the 929 had a recall on this. I tore down one of the first engines in 93-94.


Not sure if this is a good idea now,But in 1986 I worked at a Pontiac/Jeep dealer.We had several jeep products come in with Carbon buildup/knock
The service manager would rev the engine to about 2200rpm and pour a half glass of water slowly in the carb......it worked.

It was a long time ago but that is how I remember it........My dad used to do the same thing with ATF on old chevys.
 
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gpracer1

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Not sure if this is a good idea now,But in 1986 I worked at a Pontiac/Jeep dealer.We had several jeep products come in with Carbon buildup/knock
The service manager would rev the engine to about 2200rpm and pour a half glass of water slowly in the carb......it worked.

It was a long time ago but that is how I remember it........My dad used to do the same thing with ATF on old chevys.

I have done the same many times.
I love it when people tell you it will hydrolock or some other crap, then watch as I pour half a gallon right in at 4000 rpms, and I really mean pour. :)
 

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