I am recently having some problems with a tapping noise that is coming from the engine. It only lasts for about 3 or 4 minutes and only happens at startup. When I opend the hood to see what was going on. I saw that the belt was moving back and forth and the reason it was doing that was one of the wheels that the belt goes around ( I believe it was the wheel next to the mouting bracket and servo pump) was going back and forth. It was in turn pushing a triangular metal up and down ( I really don't know what his is called but I can see from the top when I open the hood). That was what was making the noise. After about 3 minutes this tops and the engine purrs like a kitten.

I did some research on thi topic and found the following explanation by Joe Schaefer. Does this also explain my problem?

Any other ideas?
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posted by someone claiming to be Joe Schaefer on Sat May 5 18:21 UTC 2001

Ron,


The noise that you are hearing is indeed piston slap. It isn't, however, a design flaw or anything wrong with the engine. You mentioned that it only occurs when the engine is cold...This is because these engines use forged aluminum pistons, as opposed to cast ones. They are more susceptible to size changes due to heat. Every turbocharged Volvo I have ever owned has had this symptom, and it is perfectly normal with a cold engine. Volvo designed these pistons to fit loosely in the cylinders when cold to allow for more expansion when hot(a turbocharged engine generates more heat in the cylinders than a normally aspirated one). It should go away when hot, as you have described. Anyway, I hope this helps...