[shachlo]

I'm driving '05 330i w/ true 62k miles on it. Recently I've noticed that the engine produces some kind of whining/squealing noise at idle:

Can it be belt/pulley/sound of water pump dying or something even worse?

I've tried using search but seems that every time the noise described as whining/squealing was in fact different from mine. Any input will be appreciated

[VanBMW335]

Could be serpentine belt.. I lost mine after ignoring a whiny noise for a few days ... Best to get it checked out right away before the car dies on you and you have to get it towed.

[mlifxs]

does it make the sound when you're driving? go away when you step on the gas? go away if you turn car off and restart? i had the above happen, made a similar sound
http://www.e90post.com/forums/showthread.php?t=691932

[mlifxs]

another thread, similar problem?
http://www.e90post.com/forums/showthread.php?t=1235420

[shachlo]

Originally Posted by mlifxs

another thread, similar problem?
http://www.e90post.com/forums/showthread.php?t=1235420

The noise I have is much quieter - it can't be heard from inside, so I'm not sure if it happens while Im driving. I asked a friend to press gas while stationary and the noise becomes even less noticeable – but doesnt go away completely.

Turning engine off/on doesnt help - it happens every time. I never had Check Engine Light, but see some belt movement from side to side when the engine is on (like 0.2 inch)

[shachlo]

Visited mechanic today: belt, pulley and tensioner are in good condition.

Noise source remains a mystery

[frenchi]

Alternator pulley bearing,remove the belt and check it

[mlifxs]

try opening the oil filter cap when the sound is occurring to see if there's pressure fighting it. if it's hard to open it may not be the belt.

[ajaye]

I battled with a similar sound for the first year with the 328...I replaced a bunch of stuff at once after several on the go-around that finally got rid of it so I can't say for sure what it was but if I had to guess, I'd say the hairline crack in the valve cover under the Valvetronic motor was the culprit. Seeing as you have a 2005, that's probably not your issue, however, make sure you do not have any broken valve cover bolts.

I also had an alternator that failed (internal bearing, not pulley) that made some whistling-type noise along with a metal rattling.

[e90-328i]

Long shot,,
I had a faint whistling type of sound on my n52 at idle. I had not tightened my oil filter cap tight enough.
May not be that,, but a quick easy check.

[shachlo]

Originally Posted by ajaye

I battled with a similar sound for the first year with the 328...I replaced a bunch of stuff at once after several on the go-around that finally got rid of it so I can't say for sure what it was but if I had to guess, I'd say the hairline crack in the valve cover under the Valvetronic motor was the culprit. Seeing as you have a 2005, that's probably not your issue, however, make sure you do not have any broken valve cover bolts.

I also had an alternator that failed (internal bearing, not pulley) that made some whistling-type noise along with a metal rattling.

Im not rly good at this, but wouldnt it be that the sound pitch would change with RPMs if it was a crack in valve cover? The noise I have is pretty constant.

Thank you everyone for trying to help out, Im signed to another mechanic tomorrow. Will update the thread.

[mlifxs]

google "pcv whistle bmw" and see how many hits. my point is maybe not valve cover but other pcv / vacuum related.

I'm not saying I know, just throwing it out there.

good luck

[KiwiRD]

It's possible you are hearing the symptoms of a distorted oil filter element. This is common where non genuine filter elements (which are a little taller than the genuine ones) are used. When the filter cap is tightened, it compressed the filter and distorts it inside the housing. As the oil passes through / over the filter, it creates a whining / whistling sound that is very audible at idle. Use the screw driver stethoscope method to test - place the tip of a flat bladed screwdriver on top of the oil filter housing and listen through the handle to see if that's what it is.

[bNks334]

I had a whirring noise like this start happening while at the track. Scared me since it sounded like it was coming from the engine rather than the pulleys or belt. I took a look at my oil filter and sure enough:



This is a K&N filter I put in 3 weeks ago (between bmw changes). Seems like it can happen to any brand even OEM MANN. I probably didn't seat the filter down properly before torqueing the filter cap and it caved upon tightening. I'd take a look at your filter for sure.

[iDELT11]

I hate to bring back on old thread but did you find out what was making the noise? My car is making a similar noise that goes away with bringing the rpm's to a 1000.

[Saxrasta]

If the whistling noise doesn't change pitch with rpm speed, it very well could be crankcase ventilation problems. This is a high dollar repair that is very involved. The entire valve cover (whole top of engine in this case) must be replaced and while apart, you may as well have sensors inside replaced because they will go bad too if they haven't already. Looking at approx $1,100-$1,500 at a private shop. Over $2,000 at BMW. Be especially careful about other sounds the car is making during idling. If you hear a rattling sound similar to a diesel, stop driving the car and get it repaired immediately! My timing chain went out (either broke or came off somehow) and now I'm facing engine replacement. Thanks BMW