It piston slap from oil through the PVC valve?
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TECH Fanatic
Joined: Nov 2001
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From: Iowa :-/~
It piston slap from oil through the PVC valve? I read in a post a person elude to this. It this a possibility? My car started to have piston slap but only until it warms up, then it goes away. I'm not to worried because I know before something happens I'm sure I'll be installing forged parts. I just would like to know if this is true so I can install a "LS1 approved" PVC oil catch can. <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />
Launching!
Joined: Sep 2002
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From: Clinton Twp. Mi
Re: It piston slap from oil through the PVC valve? The PCV valve has nothing to do with your pistons slap. Piston slap is common on all newer cars, especially on aluminum block cars. It just has to do with the pistons be cold and warming up to temp. Once they go through there expansion they are quite, so after they have run for a few minutes. If piston slap continues after it is warmed up then you might be looking at a different problem.
Thanks,
Chris Gelineau
Diamond Pistons
877-552-2112 toll free
Thanks,
Chris Gelineau
Diamond Pistons
877-552-2112 toll free
Teching In
Joined: Nov 2001
Posts: 9
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From: Painesville Twp., Ohio
Re: It piston slap from oil through the PVC valve? I think oil getting through the PVC system can cause deposits on the pistons or valves that in turn causes a cold knock. My girlfriend has a 99 Z-28 that had a similar problem to what you describe. It had this loud knock that only happened when the engine was cold, and mostly in the winter months. Soon as it warmed up, it was quieter, but still knocking slightly. Sounded like a rod bearing though, not quite like piston slap.
She would take it to the dealership for service and they would use Seafoam, or GM Top Engine Cleaner and let it soak overnight, and the problem would clear up for a few months. The dealership told her it was from her using Sunoco 94 gas, that was causing deposits to form, and to start using 87 octane only. This same dealership did all her oil changes using whatever 5W30 dino oil they had. First I pulled the intake and cleaned it, then I started doing all her car maintenance using synthetic 10W30 oil, and did the vertical PVC mod, and this knock went away, and has been gone ever since.
She would take it to the dealership for service and they would use Seafoam, or GM Top Engine Cleaner and let it soak overnight, and the problem would clear up for a few months. The dealership told her it was from her using Sunoco 94 gas, that was causing deposits to form, and to start using 87 octane only. This same dealership did all her oil changes using whatever 5W30 dino oil they had. First I pulled the intake and cleaned it, then I started doing all her car maintenance using synthetic 10W30 oil, and did the vertical PVC mod, and this knock went away, and has been gone ever since.
