high pitch noise at cold-start

[hucqym]

so for the last couple days I've noticed a shrill noise at cold start. Sounds almost like metal against metal and lasts about 30s or so. If I then turn off and start engine again, it doesnt happen. Any clue?

My drivebelt seem to be in good condition. All other bearings and idler pulley seem smooth without wobble. The alternator does have a click when I rotate it back and forth but then I dont know if that is abnormal.

I may suspect the coolant pump giving away but the momentary noise just on cold start surprises me. Any other possible suspects?

[Loren]

If you take the belt off you can check each pulley and also rotate the water pump by hand looking for wobble.

Although... I have seen water pumps where the bearing just fails and there is little or no wobble (until it disintegrates).

[pk2]

Sounds like a thing called a Bendix in your starter although 30 seconds is kinda long. The bendix is kinda intermittent to. But it does make a teeth gritting screech just as the car kicks over.

It's not real hurting anything if that is the problem.

Regards, PK

Edited October 16, 2010 by pk2

[hucqym]

If you take the belt off you can check each pulley and also rotate the water pump by hand looking for wobble.

Although... I have seen water pumps where the bearing just fails and there is little or no wobble (until it disintegrates).

Yes thats how I determined all pulleys were fine. I'll start with the belt off on the next coldstart to see if the noise is related.

Serves me right for using a cheap *** water pump the last time :P ...failed in about 1.5 years.

[hucqym]

...so it did turn out to be the waterpump.

made a huge noise yesterday (fortunately I was close to home). got the drive belt off and checked all bearings again and water pump was gone beyond doubt!

so its definitely going to be a porsche part this time