Hi, I have a 2012 s80 t6. It makes a whistle noise at idle. The noise disappears right after I press the gas even gently. So I hear clearly it comes and go. Only hear it after car warms up. No check engine light. No rough idle (600rpm at idle). I just replaced pcv and vacuum pump seals. Nothing changes. I appreciate your comments!

 

I have a 2008 S80 3.2, experienced a whistle too. Try this... At idle, with whistle present, pull the oil dipstick out a few inches. Does whistle stop? If so, it is the oil breather box mounted on the top and rear of the engine near firewall. A flap (?) Inside it wears out. Cost me 500$ US 5 to 7 years ago at a dealer to replace and have installed. The part is bolted/screwed into engine with 8 easy to get to screws. There is no mess, might be an electric connection too. Now I know that I could change it out myself. I was traveling and had no tools. Hope this helps.

 

Thank you for comment. It does not stop when pulling the oil dipstick. Nevertheless I go ahead to change pcv on the breath box since it is only $20. A whole breath box costs $200. The diaphragm looks good unfortunately. My next guess is a worn pulley. Alternator decoupled pulley?

 

I get my pulleys replaced when I replace the belt around every 125,000 miles, so Ive never had any pulley issues. Best of luck with your solution.

 

Just update in case others are interested in. Since the car has a high mileage, I just replaced belt, idler pulley, tensioner, water pump, and alternator decoupling pulley. Since I replaced the water pump, I also changed coolant. The noice is Gone! Now very smooth. The total cost is about $200. It took me four hours.

 

Your own labour obviously. $200 is parts only. Seems very inexpensive.

 

that’s correct. Very happy at the end.