Loud engine whistle

[Jsibilia]

I have a 2003 S80 with 2.9L Normal asperated with 135,000. My engine has an intermittent whirring noise that is loud and turns heads. When I remove the oil cap or dipstick to break vacuum, it immediately stops. The engine misses and tailpipe sputters, when I rev the engine in nuetral, it some times goes away, It tripped a code lean idle off bank 2 (1,800RPM) but went away after two days. When it runs properly, I pulled 17.3 hg vacuum, but when it acts up, goes 10 hg with a slight fluctuation. Thanks for any insight . . .

I spotted this post, but my car has an oil trap and not a pvc valve that I know of and I changed dipstick o-rings and new oil cap but still acts up intermittently:

Re: 2002 S80 2.9 engine whistle
by vegasjetskier » April 24th, 2009, 5:06 pm

Sounds like you've got intake manifold vacuum applied to the crankcase. My guess would be the PCV system is messed up. I'm not sure if your car has a PCV valve on it or not, but if it does that is probably the culprit - stuck in the open position and constantly appying vacuum to the crankcase.[/size]

[fn42]

Have you pulled the lines before the throttle body? you'd see some oil if it was in fact the oil trap. it sounds like you have some kind of air leak issue. Do you know that the ETM is operating correctly - does it idle smoothly (no rpm fluctuation)? If you do have oil going through the PCV lines, you might have crap all in your ETM causing it to not function properly.

the whistle is a common problem... I have a faint whistle in mine at ~2k rpm