Intermittent knocking noise... Any ideas

[NickP_S2]

I've been experiencing a knocking noise which at first I thought was the exhaust/manifolds knocking against the chassis. I thought it was this as the noise only started after I had a new exhaust fitted.

I had the exhaust mountings checked and everything seems OK. So now I'm at a loss to what the source of the noise might be. I suspect that it may have something to do with the water pump but normally these make a whinning noise I think. Performance of the car has not been effected but the noise does sound rather nasty, especially after a bit of a run. It sounds like a ball bearing inside a washine machine!! The noise does not alter when I increase the revs but it is more apparrent when at idle (this may only mean that road/air/exhaust noise hides the knocking). The alternator is working fine.

Does anyone have a sure fire method for finding the source of this noise, or has anyone had a similar problem?

[pantani201]

If its the water pump you should be able to feel play in the bearing when you tug on the pulley.

[Pies]

Somebody hasn't dropped a ball bearing into your exhaust ?