[TeamShades]

Hi all,

I've resorted to creating an account on here, as my typical Indy was unable to diagnose the issue, and now the car is sitting in a dealership. I've put the link to a video of the noise at the bottom here. The noise begins ONLY when the A/C is on, and typically the car is warmed up and moving slowly in drive/reverse. Typically it starts when stopping at a red light or parking the car.
The only way to get the noise to stop is either shutting the car off, or dropping onto a highway and moving up in gears (consistent gas/higher speeds).

I duplicated the issue for my typical guy, who had two techs looking through the car under the hood with stethoscopes. They found that the noise was coming from under the valve cover, but they did not have the tools to remove the full cover from a BMW and check. They told me it was NOT an AC compressor issue or a belt issue. I called again today and confirmed with the tech who reviewed it last week that the AC compressor was near silent, and the noise continues even after shutting the AC off.

I then took the car to a local BMW dealership as my typical guy couldn't diagnose it. They have deemed it as a AC compressor clutch failure, and continually try to claim the AC compressor is what is making the noise and needs replacement (stark contrast to my indy guys). They have seen this video, however I do not believe they have fully heard this noise in person, which is what I will try to have them do tomorrow. They have a large list of incredibly expensive repairs/replacements (i.e. valve cover gasket, tensioner/serp belt, oil filter housing gasket, and oil pan gasket). From their video, it doesn't look like any of the leaks are major, and I do not have any major issues with oil loss. I had sent the video to a BMW tech near me, and he warned me it could be a timing chain failure, which could damage the engine.

I've heard a bunch of different things now, and will try to get the dealership to correctly identify this, but for now has anyone had any similar experiences with this vehicle or N52 engine? Thanks!

Link to vid:

Different link if above doesn't work : https://drive.google.com/file/d/1AnZ...ew?usp=sharing

[beegeezy]

If it makes the noise only when the a/c is on, the compressor clutch or compressor clutch bearing is the only thing that makes sense.

[Surly73]

It really sounds like failed CCV and that's air screaming past the main seal. Pull the oil filler cap, you'll probably find very high vacuum and the noise stops once it's pulled. If all true, your indy mechanic will have to replace the valve cover. It is odd that it only makes the sound with AC on but try what I mentioned, it's free to try.

Also - a 2011 528i can have either the N52 inline 6 which is normally aspirated, or the N20 inline 4 which is turbocharged. Different parts, different behaviour of the vacuum system...

[ the bad news: I honestly didn't even read your text before starting to post what it was. I have not experienced this failure personally, so it's not like I recognized the noise. I edited my text after going back and reading your description, and feel even more certain when you said that mechanics used stethoscopes, located the noise at the valve cover, and are still confused. If it turns out that I'm right, you need new mechanics. They should know this. If your oil filter housing gasket is leaking, you need to do that job, and change the serpentine belt.]

[TeamShades]

Appreciate the replies. I still do not believe the dealership has heard the full noise as of yet (apart from video), and will try to have them test around that. So far they have just heard "a noise" from the AC compressor, which doesn't mean much to me unless its the deafening noise from the video.

I will certainly mention the CCV as I'm aware of them being failure prone, however I really have never had issues with oil loss (even with 3 leaky gaskets!). Hopefully can get this resolved this week, massive headache for sure. If anyone else has suggestions please let me know!

[chipguy]

I believe using a mechanics stethoscope would help pinpoint the source of this noise.

[TeamShades]

I finally had to just go into the dealership to duplicate the noise for them (they had spent hours driving the car to no avail). Was able to do so within 10 minutes and brought the car in screaming.

Surly73 You were completely correct in your guess, I appreciate the response greatly. The technician played around with the valve cover for a few minutes and came to the same conclusion, as the noise quit when he removed the cap. Will need main seal replacement and valve cover replacement. Still unsure what the A/C has to do with anything, but I will not be replacing the compressor fortunately.

Will get to the serp belt/tensioner/oil filter housing gasket soon, but not at dealership prices.

[beegeezy]

Weird that the a/c compressor was affecting it! Glad you got it figured out.

[Surly73]

Glad you're on track to getting it fixed!

Running the AC and using the brakes can alter the vacuum conditions in the engine (though hardly at all in Valvetronic engines compared to more traditional designs). Using the brakes always triggers a failed turbo wastegate solenoid (a device in the vacuum system) to start honking or buzzing on my F10. It could be that certain disturbances in system vacuum trigger the CCV into a failed mode and then things go haywire.