Hey guys, I'm new to the forum but not new to turbo vehicles. My girlfriend owns a 2005 Volvo S40 T5 and she's encountering some issues with it that hopefully you all can help me diagnose.

When the car idles, there is a whirring sound coming from the engine. I'm not really sure how to better describe it but it's loudest when I put my ear near the valve cover. I had thought that maybe it was a belt, so I attempted spraying belt dressing. This worked to no avail and I was honestly puzzled. She took the car to a mechanic who also couldn't figure out what the story was, but said it was most likely the turbocharger. This strikes me as odd, considering I had blown quite a few sets of stock turbos in my Supra, and I was unable to find any of the telltale signs of a failure or pending failure. The sound is constant, it does not increase as the vehicle accelerates through the rev range and there is no smoke coming from the car. Oil level has also remained the same.There are also points in time where the sound is not present: such as initial daily start up but after a few minutes of use, it appears.

Other things that had entered my mind where the alternator, but the battery has remained fine. Also the water pump, but the temperature of the car has not at all fluctuated. The car has 52k miles on it and will be venturing off to the dealer on Friday if I can't pinpoint anything.

If there is any additional information that would be helpful to you guys, I would greatly appreciate your assistance.

 

Next time it does it either pull the dipstick or open the oil cap. If it stops the Vent box is bad and will need to be replaced.

Bad part is the oil filter housing is part of the vent box.

 

Thanks Tech, I'm going to have her do that when she gets out of work.

Any other ideas?

 

Sorry not right off hand thats the only thing I have really ever seen wrong on them.