Just went through all engine noise threads and did not find anything even close to what my 2000 Carrera is doing.When it gets to operating temperature it first starts like a whistling noise and gradually increases to a very loud noise almost like a serpentine belt slipping on a seized pulley.But belt and pulleys are fine ,than I thought it may be a worn throwout bearing because when you step on the clutch it slightly changes.So pulled the tranny out,all parts related to clutch are fine.Out of desperation started the engine without the tranny and clutch (after a clutch switch bypass) - same thing.
This is the wierd part when it starts making that noise and you pull the engine oil dipstick out to create vacuum leak it goes away. Anybody had a similar problem?Your help is greatly appreciated

 

If you create a large vacuum leak (by pulling the dipstick) and it goes away, I'd bet you have already found the problem. Odds are it is a small leak at the end of a vacuum line and the whistle you hear is the sucking in of air. When you pull the dipstick you create a much larger hole for air to be pulled in (path of least resistance) and thus no more air is being sucked by the leak.

I would try to listen to the noise and find the approximate area the noise is coming from. Then start checking hoses in that area, I would guess you will find a cracked or loose hose.

Then again, I could be smoking something, as I don't know Porches very well.

Just my 2 cents,

James

 

Thanx,
but locating the leak is the acctual chalenge as everything is under the intake behind the alternator,you have to disasemble "half of the engine" to get to the plumbing and than cannot start it.Visually everything looks OK but those vac. leaks can be tricky....Thanx for your input.I'll keep searching

 

Got it
Small crack in oil separator was making the whistling noise!It is best to get to w/transmisison removed

 

No need to pull the tranny to get the OAS out. It is a tight fit, but it will come out.

 

Since I had the tranny out to check the clutch it made it much easier to get to.and on a C2 its not such a bad and long job.
Thanx