1994 944t 208K

Pulled the wife's car in for a little maintenance this morning and hear a "rattling" noise under the hood.

Using a piece of heater hose to my ear I found the source to be on the front of the engine in the vacinity of the waterpump.

Checked the pump shaft for lateral play and found none (pump has about 30K on it).

Pulled the plug on the timing cover and listened with the hose thinking it might be the bearings in the tensioner, but the noise was not coming from there.

Removed the drive belts one at a time: AC belt off, no change; alternator belt off no change; power steering belt/waterpump belt off and the noise was gone.

I assumed this confirmed my thoughts that it was the waterpump, but an additional check of the shaft confirmed no play and spinning the pump by hand revealed no sound.

I replaced the power steering/waterpump belt and started the car. Absolutely no rattling sound. The belt tension was not changed from where it was originally because I simply rolled the belts off and rolled them back on. Replaced the other two belts and the sound has vanished.

If you listen to the video you will hear that it is a very metallic sounding rattle. The camera was placed right in front of the waterpump (no mechanical fan on the car). I thought perhaps it was a loose impellor but why would it go away by simply removing and replacing the belt?

Click here to listen to the recorded sound.

Thanks,
Randy