technical N55 pcv failure?

[Liam H]

Hi everyone. My 2012 F30 335i N55 pwg has started developing a chirping/squealing noise almost identical to the sound i had when i had a bad pulley. I replaced the tensioner, idler pulley belt about 3 weeks go. The noise has returned, but i have absolutely no leaks infront of the engine and the belt is fine. NOTE: This noise ONLY appears when I've driven a while and the engine is hot (oil temp at 105-110°C. I performed the test where i remove the oil cap to see if the noise continues, as soon as I remove the oil cap, the noise dissappears. Is this then confirmed its my pcv or valve cover? There isn't any oil leaks around the valve cover either, and no DME error codes at all which is strange to me. Ive scanned multiple times for codes for vacuum leaks, but nothing.

The car is currently on stage 1 MHD, with upgraded charge pipe and catless downpipe. I've hear that tuned N55s go through PCV and valve covers quite quick, my valve cover is about 3 years old i think.

Any help or tips would be appreciated.

 

[bmw fanatic]

Hi everyone. My 2012 F30 335i N55 pwg has started developing a chirping/squealing noise almost identical to the sound i had when i had a bad pulley. I replaced the tensioner, idler pulley belt about 3 weeks go. The noise has returned, but i have absolutely no leaks infront of the engine and the belt is fine. NOTE: This noise ONLY appears when I've driven a while and the engine is hot (oil temp at 105-110°C. I performed the test where i remove the oil cap to see if the noise continues, as soon as I remove the oil cap, the noise dissappears. Is this then confirmed its my pcv or valve cover? There isn't any oil leaks around the valve cover either, and no DME error codes at all which is strange to me. Ive scanned multiple times for codes for vacuum leaks, but nothing.

The car is currently on stage 1 MHD, with upgraded charge pipe and catless downpipe. I've hear that tuned N55s go through PCV and valve covers quite quick, my valve cover is about 3 years old i think.

Any help or tips would be appreciated.

I've had something similar occur on my 135i N55. Turned out to be a blocked breather pipe on the valve cover. Unfortunately this plastic cover and breather pipe is one unit ( so I was told by BMW ). Had it replaced and it sorted out the problem.

 

[Liam H]

I've had something similar occur on my 135i N55. Turned out to be a blocked breather pipe on the valve cover. Unfortunately this plastic cover and breather pipe is one unit ( so I was told by BMW ). Had it replaced and it sorted out the problem.

That could also be possible

 

[Teezoh]

as soon as I remove the oil cap, the noise dissappears

This 100% points to your pcv.

The diaphragms inside tears and you're just gonna waste your own time and money getting just that replaced with the kits available.

Time for a new tappet cover.

 

[Liam H]

This 100% points to your pcv.

The diaphragms inside tears and you're just gonna waste your own time and money getting just that replaced with the kits available.

Time for a new tappet cover.

my shop did the pcv only, not the whole cover, i'll see tomorrow if the issue continues

 

[Liam H]

So unfortunately the valve cover was replaced but the car still is giving off the noise, the sound seems to be coming from the alternator's side.

NOTE The noise only appear when the engine is hot after driving for a while

 

[Liam H]

This 100% points to your pcv.

The diaphragms inside tears and you're just gonna waste your own time and money getting just that replaced with the kits available.

Time for a new tappet cover.

Check my reply below

 

[Teezoh]

So unfortunately the valve cover was replaced but the car still is giving off the noise, the sound seems to be coming from the alternator's side.

NOTE The noise only appear when the engine is hot after driving for a while

Did they only replace the PCV or the entire valve cover now? Seems unclear.

You mentioned you did the oil cap test and the squealing noise went away, that points to a PCV problem. Besides that for confirmation you can do a lighter test too, hold it near the nipple outlet, if it sucks the flame in there's a problem.

Troubleshooting via the forum for guidance with videos is hard, maybe give Ashley from Xcede a call?

 

[Liam H]

Did they only replace the PCV or the entire valve cover now? Seems unclear.

You mentioned you did the oil cap test and the squealing noise went away, that points to a PCV problem. Besides that for confirmation you can do a lighter test too, hold it near the nipple outlet, if it sucks the flame in there's a problem.

Troubleshooting via the forum for guidance with videos is hard, maybe give Ashley from Xcede a call?

Car is at BMW now, hopefully they find the issue.

 

[Liam H]

Update: They think its my belt tensioner, has quite a lot of play on it, the pcv has been tested and is fine, and no vacuum leaks. Hopefully the new tensioner will fix the issue.