[s_ribs]

RESOLVED: replaced the Serpentine belt, tensioner and both idler pulleys and the noise has disappeared. Bearings in all 3 pulleys had play in them which could be the culprit.


I have a noise coming from my engine and curious if anyone has experienced this or knows what this could be? I hear it while driving the car or when reving in neutral, and it always starts around 1500 rpm.

Sounds just like this video:

However, I pulled the filter and it a) was not collapsed and b) was already a Mann filter. I had a new Mann filter in hand so I the filter and o-rings anyway as a cheap check. No change.

This car is new to me so here's the quick summary of my 5 weeks of owning it:
Feb 2, purchased this vehical with 97,600 miles. Note that I purchased it out of state, drove it home, and do not recall hearing this noise ever.

Feb 12 Dropped the car off at the shop. It had oil leaks (known when purchased) and I wanted them repaired right away. (oil filter housing gasket and oil pan) by a reputible BMW indi shop. They also changed the engine oil, coolant, brake fluid, and I had them replace the front control arm bushings since an alignment was required.

Feb 23 Picked up the car from the shop.

This is where I question my memory gets since I only had the car for one week before it was in the shop for two weeks. Kind of felt like I just got a "new to me" car again at that point. I heard a slight noise after I picked it up, post repairs, but it didn't seem loud or anything. The serpentine belt was pretty coverd with oil (they cleaned it and said no need to replace) so I assumed it was just a minor belt noise.

I work from home so I don't drive much, which is why it's taken me two weeks to really start questioning this noise and make a post about it.

Additional disclosure: I have not called the shop yet but I do plan on calling them soon. Wanted some opinions from you all as this shop is an hour away and therefore not super convenient to just drop my car off.

This car came with a 3 month warranty (which amazingly covered all of the oil leaks) so if this is a repair shop item I'll definitely bring it back. If it's not then I will likely tackle this myself once I know where to begin.

[Surly73]

Does your oil filter cap have the center insert in place and intact, including the green O-ring on the tip?

[s_ribs]

Originally Posted by Surly73

Does your oil filter cap have the center insert in place and intact, including the green O-ring on the tip?

Good question, yes it does. I even replaced the green o-ring when I pulled the filter out to check.

I do not specifically look for the spring though (idk if it’s even possible for them to come out).

Not much point in throwing money to check but I did wonder if there could be something sticking or not working correctly and would warrant replacing the oil filter cap assembly. I can’t find anything to support that unless it’s broken.

Edit: adding the one picture I took after pulling the filter:

[s_ribs]

Just ordered a new BMW oil filter cap (and another Mann filter) cause it'll take a few days to arrive. Watched enough youtube videos to see that weird things happen from the cap as well that I want to rule it out as a culprit. Telling myself it's plastic and doesn't hurt to swap it out as preventive maintenance.

[Unspec]

Does the whine go away at a certain point, or is it constantly there after 1500rpm?

[s_ribs]

Originally Posted by Unspec

Does the whine go away at a certain point, or is it constantly there after 1500rpm?

It's hard to tell because the engine sound quickly overpowers this sound over 4k rpm. My guess is that it stays constant. I tried taking some video clips with my phone and will see if I can figure out how to post them.

One item of interest is that I went back and forth with the youtube clip above and the recordings I just made, and my noise is bit higher in pitch but otherwise very similar in nature.

Without question, it happens when revving in Neutral or while driving, and when driving it is in every/any gear. Always rpm dependent. No change in tone or volume, etc. based any other variable that I can think of.

[s_ribs]

https://youtube.com/shorts/_587hB-FYMg

Testing… in standard comfort mode with a quick pull in first gear. If the video works I have a few more to share from different perspectives. It’s quite low volume in the cabin so it’s hard to hear.

[s_ribs]

Driving, shifting manually (tried to accelerate slower to accentuate the noise):
https://youtube.com/shorts/iQ6FlKK7GO8?feature=share

Revving in neutral, in cabin:
https://youtube.com/shorts/XpRn8XLd3n0

Revving, phone in engine bay near to oil filter housing:
https://youtube.com/shorts/BXqMO48FXCo

[ChiltiCoatl89]

Hard to hear anything other than a nice Engine note,there are others here who may be able to identify it. In regards to your video before your other posts.

[ChiltiCoatl89]

Originally Posted by s_ribs

Driving, shifting manually:
https://youtube.com/shorts/iQ6FlKK7GO8?feature=share

Revving in neutral, in cabin:
https://youtube.com/shorts/XpRn8XLd3n0

Revving, phone in engine bay near to oil filter housing:
https://youtube.com/shorts/BXqMO48FXCo

Definately hear that odd noise in your last video here.

[Conserve]

Feb 12 Dropped the car off at the shop. It had oil leaks (known when purchased) and I wanted them repaired right away. (oil filter housing gasket and oil pan) by a reputible BMW indi shop. They also changed the engine oil, coolant, brake fluid, and I had them replace the front control arm bushings since an alignment was required.

Based of above, do you know if they primed the engine after work they performed?

[s_ribs]

Originally Posted by Conserve

Feb 12 Dropped the car off at the shop. It had oil leaks (known when purchased) and I wanted them repaired right away. (oil filter housing gasket and oil pan) by a reputible BMW indi shop. They also changed the engine oil, coolant, brake fluid, and I had them replace the front control arm bushings since an alignment was required.

Based of above, do you if they prime the engine or not?

It was specifically noted in their service notes that engine needs to be primed so I assume that it was done.

[Conserve]

Last video can hear odd noise. Can you remove oil fill cap and rev it same as you did in last video. I am curious if CCV in valve cover is the culprit. Keep the phone in the engine bay.

[s_ribs]

Originally Posted by Conserve

Last video can hear odd noise. Can you remove oil fill cap and rev it same as you did in last video. I am curious if CCV in valve cover is the culprit. Keep the phone in the engine bay.

https://youtu.be/fP317x9xAck

Good idea, here you go.

[Conserve]

See this link. Is only one page.

https://www.e90post.com/forums/showthread.php?t=1299657

Back to what I asked and sound clip you provided. Is hard to say just sound and no picture. see real engine in that condition.

Is it possible for you to remove vent hose #21 and check with flashlight and wooden stick if the passageway in VC filled with oil or not. I am still suspicious of VC.

[s_ribs]

Originally Posted by Conserve

See this link. Is only one page.

Back to what I asked and sound clip you provided. Is hard to say just sound and no picture.

Is it possible for you to remove vent hose #21 and check with flashlight and wooden stick if the passageway in VC filled with oil or not. I am still suspicious of VC.

Will do, hopefully tomorrow. Wish me luck that the hose doesn’t fall to pieces.

I genuinely appreciate everyone’s responses and advice!

[Conserve]

Wish me luck that the hose doesn’t fall to pieces.

Be prepared for replacement most likely and it is not cheap.

[s_ribs]

Ordered a new breather hose in anticipation that it will fail and it should be here Thursday. Until then...

[s_ribs]

I've listened to the sound clips a few times and it is interesting that the pitch changes. Pitch is higher when revs climb, and then a little lower as revs fall, which I assume means the change is from being on throttle vs. off throttle (or on boost vs. off boost?). Volume is roughly the same, only pitch changes. Hhmmm.

[Unspec]

Does opening the oil fill cap make the noise go away? If you had an OFHG leak, it could actually be your serpentine belt being degraded and squealing.

[s_ribs]

Originally Posted by Unspec

Does opening the oil fill cap make the noise go away? If you had an OFHG leak, it could actually be your serpentine belt being degraded and squealing.

No, opening the fill cap did not eliminate it. See this clip: https://youtu.be/fP317x9xAck

I have wondered about the belt but the sound just doesn't match up with any belt noise I've heard before. The OFHG leak was really bad and the belt was soaked in oil. However, the tech cleaned it up and said it did not need to be replaced. I asked them at least three times to make absolutely sure the belt was fine and didn't need to be replaced. I've watched the tensioner and at idle it's dead solid, so that seems fine.

That said, I do hear a slight whistle/sqeak sound of a belt when I have my windows down and drive past an object to reflect the sound back. It's minor and nothing alarming, unless it is in fact shreaking with agony when the engine is winding up the revs.

That is another gonna fail eventually item so it wouldn't be a total loss firing it through parts cannon. Hhmmm... gonna sit on that one a minute.

[Unspec]

Replace the belt. You do NOT want that belt to come off.