Slight tapping noise when engine cold - OK?
Thread Starter
Melting Slicks
Joined: May 2000
Posts: 2,155
Likes: 17
Slight tapping noise when engine cold - OK?
Guys - I just noticed a slight tapping noise when my engine is cold - I have heard this may be normal and is called "cold piston slap" - anyone else have this problem and is it normal/ok?
Race Director
Joined: Feb 2001
Posts: 13,910
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From: Manassas VA
NoVa Events Coordinator
St. Jude Donor '14
Re: Slight tapping noise when engine cold - OK? (OliverM5)
I have heard many C5's with piston slap... Gm says its normal and not to worry about it.
Instructor
Joined: Feb 2002
Posts: 162
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From: C5 Land
Re: Slight tapping noise when engine cold - OK? (B. Stewart)
I have this "slapping" too.... :(
It takes a looong time for it to fade away, and even with a warm engine it´s noticable between idle and 1300 rpm.
I find it strange that a big manufacturer like GM can make and approve an engine with these kind of noices, and continue to sell it like that...!
The car is great, but things like the "pistonslapping" belongs in the 70´s..!
It takes a looong time for it to fade away, and even with a warm engine it´s noticable between idle and 1300 rpm.
I find it strange that a big manufacturer like GM can make and approve an engine with these kind of noices, and continue to sell it like that...!
The car is great, but things like the "pistonslapping" belongs in the 70´s..!
Advanced
Joined: Jun 2000
Posts: 79
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From: Bloomfield Hills MI
Re: Slight tapping noise when engine cold - OK? (The Laplander)
Guys, I don't think what you hear is slapping. Most piston "slap" does not go away with warm-up. :blueangel: I believe what you are hearing is the valve train pumping up. In most production level vehicle, the lifters are hydraulic, which need oil to pump them up. When it is cold, the oil takes a while to get to the lifters and then to pump them up. I have heard this same thing in BMW's and other high end engines. Just let the car warm up a little. Depending on the temperature, this shouldn't take more than a few minutes. Piston slap usually sounds pretty loud where lifter noise is a tapping or ticking sound.
Hope this helps,
Neil :flag
Hope this helps,
Neil :flag
Instructor
Joined: Feb 2002
Posts: 162
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From: C5 Land
Re: Slight tapping noise when engine cold - OK? (cruzin')
Hi! And thanks for the answer. :cheers:
I am certain that the noice isn´t the valve train pumping up. It is a deep rattling mechanical noise. It sounds like something were loose inside the engine, like a too small piston.
I have learned from the members on this forum that it´s nothing to worry about, but it sure sounds like.. :U
Jörgen E.
I am certain that the noice isn´t the valve train pumping up. It is a deep rattling mechanical noise. It sounds like something were loose inside the engine, like a too small piston.
I have learned from the members on this forum that it´s nothing to worry about, but it sure sounds like.. :U
Jörgen E.
