2CarPros - Car Questions & Answers

1998 Buick Century Repair Question


Topics covered: Piston, Noise, Engine.
Mileage: No information provided.

Asked on January 14, 2007

1998 Buick Century and rapid tapping noise

I have a 1998 Buick Century Custom with 98,000 miles on it. It is a V8.
I heard a loud rapid tapping noise that when i looked at it didnt appear to be coming from the belt and it appears that the oil is fine, I havent noticed any leaks anyway.

The sound kept up for about 15 minutes after the car was running and then stopped. Does this sound like a rod, valve or lifter problem. Or is it just the belt itself.

Could this be a omen of a bigger problems?
Avatar Asked by John C

Answer

Replied on January 15, 2007

This may be a piston slap.It cause by excessive clearance between the piston skirt and the cylinder wall.This can be cause by worn cylinders or worn piston skirts.
Usually the the noise will desapear after the engine warms due to the aluminum pistons expanding faster than the cast iron block.
To confirm this,short out the spark plug during the time the noise is heard. The noise may quiet or desapear.

Tiny Answered by mathiaso
5 questions asked
Replied on January 15, 2007

Thanks for the response, final question is there any fix to this? short of complete rebuild

Tiny Response from John C
1 question asked
Replied on January 15, 2007

Please, you must verify piston slap before putting your engine appart, or briging it to a mechanic.

Another method of diagnosing pinston slap is to place a small amount of heavy oil on the top of the piston.This is done by by removing the spark plugs and squirting the oil on the top of the piston.Rotate the engine several times to allow the oil to seep past the rings.Start the engine; if the noise is gone, the problem is probably piston slap.
When this is veryfied by you, Pm me and I will let you know what next.

Tiny Answered by mathiaso
5 questions asked