I have a 2001 S60 with 96,800 miles on it. I keep regular scheduled maintenance on it. Recently while driving after about 20 minutes, a high pitch sound comes from the engine. If I slow the car down, the noise gets higher. IfI come to a complete stop, the noise is still there, but if I place it in park the engine dies on me. It does re-start quickly. Also, if I drive faster, the noise either goes away or too low to hear. I've had all belts & hoses changed. I even had the alternator replaced because it had given me an earlier problem. Now I noticed the check engine light came on & the message saying there is an emissions problem. Now a few days later the engine light & message have gone away, but the noise problem still exists. Any help & suggestions would be greatly appreciated.

 

Could be a problem with your Catalytic converter being plugged. That might explain the noise as well as the dying. As your revs go down the back pressure builds up and chokes out the engine. Just a guess on my part.

 

The Vent box might also be bad.

 

If your car is a non-turbo (denso engine management system) Check if high pitch squeal goes away if u pull the engine oil dipstick out? if it does put your finger tip close to dipstick tube. if u can feel vacuum sucking yout finger close to dipstick tube. You will most likely have a plug PCV box or the vacuum diaphram on pcv box clogged with carbon causing excessive vacuum. in that case replace pcv box and hoses attached if possible and noise and stalling should be gone. Remember to clear Diagnostic Trouble Codes out of system.

 

Problem solved! It was the PCV valve or what they also call the "breather box" or "vent box" which was previously mentioned. Thanks for all the help!

 

How do you get to the PCV breater box on a turbo S60. I have similar symptoms. Is it under the intake manifold?

Does someone have a hose schematic?

ca

 

For S60 turbo rarely have excessive vacuum. most likely clogged and cause positive pressure in crankcase... If u have excessivecrank case pressure youcan try cleaning the PCV nipple and replace the hose. (Take whole banjo fitting out under intake manifold) cannot be lazy. Also since u are there should have remove throttle body already... spray some throttle cleaner on a rag and wipe throttle body if needed.

 

I can't find the PCV on this car. I just bought it and it has that whistle from the crankcase. Thanks in advance.

 

Thanks for posting guys, my 2006 S40 2.5 Turbo (T5) was also affected by this problem. New PCV valve assembly fixed it.