[alfredoporro]

Hello All,

I'm writing here in hopes to get more help than on the E70 X5 Forum.

N55 with 80,000 miles.

After having my valve cover replaces as a warranty job because of a leak on the rear passenger side of the engine that was sending fumes into the cabin through the vents, a whirring/screeching noise started to be more loud when the car is at operating temperature. I heard the noise before the replacement of the valve cover but it was not as loud.

Right after replacing the valve cover, the mechanic heard the noise and after looking around the engine bay and under the car, he checked the area where the rear main seal is. While the car was running, he opened the oil engine cap and the sound stopped. He told me that the culprit is the RMS. He said he didn't see any oil leaking when he was inspecting that area and that for now it is only air passing through. He said that I should replace it but it doesn't have to be right away, probably when my next oil change is due.

When the engine is running after a cold start, I don't hear the sound but after driving the car and reaching operating temperature, the whirring/screeching noise can be heard.

There are no codes and the car runs normal. I connected MHD to rear codes and everything is clear. Right after the valve cover job, I drove the car 80 miles without stopping. I was told to check faults for the following and MHD came out clear:

"If it has camshaft timing faults it is bad Vanos Solenoids. Also make sure the oil filter cap has the center tube intact that holds the oil filter cartridge. If it has eccentric shaft faults, its a bad eccentric shaft sensor.
Both these issues cause the variable valve lift to go into failsafe which creates excessive crankcase vacuum. The whistling noise is from air rushing in through the front and rear main oil seals. Creates a whistling effect"

MHD report:

- DME active codes -
None

- Misc. information -
MHD build: version 1.8
Voltage 15.07V
Last flashed file : Unknown
Factory software: 7623266
Current software: 8684966
ECU status: Normal operation

- Readiness -
Misfire: Complete.
Fuel System: Complete.
Components: Complete.
Catalyst: Complete.
Heated Catalyst: Not avail.
Evaporative System: INCOMPLETE.
Secondary Air System: Not avail.
A/C Refrigerant: Not avail.
Oxygen Sensor: Complete.
Oxygen Sensor Heater: Complete.
EGR System: Complete.


I checked the oil filter cap and the center tube was intact in my opinion. Just in case I replaced the filter and the seals but this didn't make a difference.

I would like your opinion and see if anyone has had an issue like this here.

Videos where you can hear the sound, first one is engine running cold and the second is the engine running at operating temperature where you can hear the whirring/screeching noise (noise starts at the 3 seconds mark):

https://youtu.be/qa_D7iNUmT8

https://youtu.be/y_p7hEBkzgc

[dougthe335i]

My car seems to be experiencing these symptoms right now. Did you ever figure out the exact issue?

[fastboatster]

Originally Posted by dougthe335i

My car seems to be experiencing these symptoms right now. Did you ever figure out the exact issue?

Look up “understanding n55’s pcv valve of doom” thread, or something along these lines. It shows how to test the pcv valve. Also, it has pages from some BMW service info bulletin which states that rear (and/or front?) main seals prior to some date might had manufacturing defect and tells how to check it.

[whyzee125]

Bad PCV. Very common on the N55--I'm surprised the mechanic didn't immediately figure this out especially since it changed when the new VC was installed. Likely an aftermarket one that was bad out of the box or just one that wasn't designed well. The OEM ones seem to last 80k on the dot almost everytime.