Is a tok, tok, tok, tok, type noise thats coming from the motor at idle the sound of a bigend bearing on its way out?

its louder when cold, goes away when the engine is revved above 2500 rpm (hot or cold) and comes back noticably as the engine drops down to idle. I have no knocklink activity and the car still runs fine. (2002 STi, 55000 miles)

 

No, I wouldn't say that was a big-end. With a worn out big-end you would hear a distinct knocking noise (pretty loud, you can't miss it) when the engine was NOT under heavy load i.e. at a steady speed, the sound goes away when accelerating or deccelerating. From memory, at idle you can't hear it or it is really slight.

Yours sounds like something else, it's quite a new-ish motor so you would be unluckly for it to be anything major.

 

Thanks Normski and you were right about it not being a big end or major. It is the sound of the cam belt tensioner I am told which would have been replaced on the next service. anyway.