strange sound from engine

[dsulu]

Hi Guys,

Initially I thought I need to replace a water pump on my 98 Boxster, now it seems, it may be even a bigger problem.

So here it goes,

Recently I noticed that my car would produce whistling sound around 1000~2000 rpm, especially at stop, noise is just unbearable.

So I did some research here on the forum and many of you have had this problem and it points to a failed water pump and/or pulley.

So what I did was to drive my car for a while to warm it up, the noise kicks in after the car got warmed up. Got back and then I removed the cover to gain access to the engine.

Took off the serpentine belt and started the engine and the noise is still there, sounds like it is coming from the main crank shaft "pulley" , initially I thought, this is it, the engine is on it's way to ruin.

But this is what I observed, the noise would last about 1 sec, after I turn off the engine, in fact I noticed that the crank shaft pulley would stop turning and the noise would last about 1 sec and it dies down.

Would this point to some problem other than mechanical failure of engine parts. :(

I recently changed the spark plugs, and somewhere in the forum mentioned that if the sparrk plugs weren't torqued correctly, it would also produce some strange sound.

If the problem isn't asssociated w/ the spark plugs, what other problem would it be.

Any help is greatly appreciated.

[Steve Tinker]

A loose spark plug will cause a whistling sound - so I would re-check the torque of each plug.....

The sound could also be caused by a failing AOS (air/oil seperator). To check, remove the oil filler cap with the engine idling - if the cap is difficult to remove (a vacuum) then there is a good chance the AOS is on its way out. Are you experiencing a smoking exhaust at startup - this is another classic of a failed AOS.

Hope this helps.....