High Pitch Squeaky Noises

[hunginator]

Not sure if I should be posting this in the Maintenance section so I apologize in advance if so and please move to the correct section.

My car is an E82 135i (N55) with the DCT. I'm at 93,000 miles.

At cold start, I notice a high pitched squealing noise and it gets worse as I apply minimal throttle.

When more throttle is applied, I don't hear it anymore but that could be because I have the BMW PE which may be loud enough to over-power the squealing noise. Also, this seems to disappear after the car starts to reach higher operating temps. I should also note that this noise is even easier to hear when in enclosed car parks.

Does anybody know what the potential issue could be? Also note that I had my belts and tensioner pulley replaced a year ago. Could it be the same issue again?

Thanks in advance.

[Gizmo135i]

First thing I would do is change the oil and put an oem oil filter in, it is a cheap first step. Aftermarket ones sometimes cause oil pressure fluctuations which affect the vanos and cause different issues including excess crankcase vacuum which could make that whistle noise.

Also you can try pulling off the oil filler cap while it’s making the noise and see if it goes away. The pcv valve or the vacuum chamber in the valve cover could also go bad and cause similar symptoms.

That is if corse to say the noise is coming from the engine and not the belt or something else, hard to say without seeing it.

[hunginator]

Originally Posted by Gizmo135i

First thing I would do is change the oil and put an oem oil filter in, it is a cheap first step. Aftermarket ones sometimes cause oil pressure fluctuations which affect the vanos and cause different issues including excess crankcase vacuum which could make that whistle noise.

Also you can try pulling off the oil filler cap while it’s making the noise and see if it goes away. The pcv valve or the vacuum chamber in the valve cover could also go bad and cause similar symptoms.

That is if corse to say the noise is coming from the engine and not the belt or something else, hard to say without seeing it.

Thanks for the reply. It’s definitely coming from the engine bay area and I always use OEM stuff. All my oil changes are done at the dealer. I’ll bring my car in later this week and have them inspect the belt/pulleys first and go from there.

[xrockoutx]

OFHG leaked onto your belts, now they're squealing. It's happened on 2 of my cars...check for oil residue around the OFHG or just the oil filter itself.

[ferocity02]

Possibly bad PCV system, common for it to fail at 50K miles or less. Post video of the sound to youtube.

[dtla1]

Originally Posted by hunginator

Thanks for the reply. It’s definitely coming from the engine bay area and I always use OEM stuff. All my oil changes are done at the dealer. I’ll bring my car in later this week and have them inspect the belt/pulleys first and go from there.

Try doing what gizmo suggested, turn the oil filler cap while the car is on and you can hear the sound. If there is a PCV or a minor oil leak somewhere it should go away, that would be a good indicator to rule out belt/tensioner quickly.

[hunginator]

Thanks all for your replies. I brought the car in to the dealer for some other things and the tech determined that the noise was coming from my tensioner pulley. I found this odd because the tensioner pulley was replaced last year at an indy shop with OE replacement parts.

Perhaps, the replacement part last year was faulty. I'll confirm that the noise is gone after I get my car back later this week.

[hunginator]

Noise is no longer there. It was definitely the tensioner pulley. Belt was also replaced.

[MightyMouseTech]

Originally Posted by hunginator

Noise is no longer there. It was definitely the tensioner pulley. Belt was also replaced.

[hunginator]

Originally Posted by MightyMouseTech

thanks mightymousetech!