[Wishes47]

Trying to figure out if the problems I am having are due to TENSIONER PULLEY, VANOS SOLENOID, VALVE COVER, BREATHER VALVE, or all of the above. Hopefully some of you can help shed some light. In the past 2 days I have paid $780 in repairs, but continue to have the problem. If possible, I would like to get somewhat of an understanding of what may be going on so that I am not completely ignorant when I go back to this mechanic. Please help.

About 2 weeks ago I started hearing a whistling/squealing/chirping noise coming from under the hood for about 2 miles, then when i turned the car off and restarted it later, the noise was gone. A friend said it sounded like a wet belt, since it was raining. Didn’t make the noise again for almost a week, then started again and the service engine light came on. The noise is very random and I only hear it when I begin to slow down to a stop. It goes silent on acceleration. There was only one time that it continued while idling. The only thing that stops the noise is shutting the car off and restarting, but the noise returns later. This could be an hour or a day later. Then the car started randomly losing power. It would suddenly shut off when I stopped or while driving, but it would start right back up with no problem and be fine for while. The shut offs only occur shortly after the noise starts. Went to Auto Zone and the machine showed a fault code for my fuel cap only. I replaced the cap, but the light didn’t go off.

My father suggested a a bad belt/pulley and sent me to his mechanic. His mechanic got a fault code relating to the VANOS SOLENOID, which he replaced and reset the computer. The car stopped shutting off, but two days later the noises started up again and the service engine light came back on. When I took it back to the mechanic, he then received a different code relating to the TENSIONER PULLEY. He didn’t have time to fix it, so I took it to the European Auto shop. By the time I got to the shop, the service engine light was off (never came back on). In addition to the TENSIONER, this shop said I needed a new VALVE COVER and VALVE GASKET. I didn’t have the money to fix everything, so they suggested I do the TENSIONER and said this was causing the problems. I got the car back today and 30 minutes later the noise started again. It still hasn’t shut off since the VANOS SOLENOID REPLACEMENT. I called the auto shop back and they now say it’s the VALVE COVER and the BREATHER VALVE that is causing the noise. The mechanic claims that he told that that fixing the Pulley would not stop the noise.....he never told me this.

Can anyone tell me if any of this makes sense and/or what it all means? What should the next repair steps be and what I should expect to pay (ballpark figure, if anyone has any experience with this. Also, what exactly this BREATHER VALVE

Thank you so much for any advice given.

Connie

[deansbimmer]

So much wrong to unpack here.

Valve cover leaks are common on these cars as they are magnesium. Shops will prefer to replace the cover so they don't have to work as hard to clean and prep them to get a good seal again. Zero cause of any squealing noise, at all. Same for the "breather" (Oil separator) on top of the valve cover. Doesn't influence noise.

There is no "code" for a tensioner. No idea what they were looking at. Tensioners an pullies are either noisy or they're not. They're properly diagnosed with a stethoscope. Did you replace all three tensioners and pullies? If not then you can't rule them out as the noise source.

The noise you're hearing could be the A/C compressor if it's not a tensioner or bearing. Try turning off the AC and see if they noise persists. The alternator bearings can also squeak.

[Shiza]

Well we can only help so much since we cannot see the car in person but the tensioner was a good place to start based on the noise you are describing. Unless you are having oil leak from your valve cover you do not need a new valve cover or valve cover gasket. I cannot see how those would possibly be related to a squealing noise. BTW there is no such thing as codes related to the tensioner pulley, so idk where they came up with that one. Is the noise coming from the front of the engine?. If the noise is coming from the front of your engine it could be related to your water pump. How do your coolant temps look? What are the codes that the car is currently throwing?

[deansbimmer]

Also, your profile says you have a 328xi. This is the M3 forum so the systems and diagnosis will be completely different than in the M3 context my response assumed. Which car is this you need help with?

[DrFerry]

My money's on what Deansbimmer said above. So it could be one or more of these items in the list below that are squealing:

1) Alternator bearing
2) Serpentine belt tensioner pulley
3) Water pump bearing
4) Air conditioning pulley bearing
5) Power steering pump bearing

Take a video with your phone and record the noise. Post it to YouTube and then comeback and link it here. There are many brains here. With a little patience these guys on this forum board will figure it out.

PS:
How many miles on the car?

[monterey]

Idler pulley is the most common for noise but it wouldn't cause check engine lights or power loss.

[ItsGary]

I had squeaking with my car, replaced the belts and it was gone. Belts should have been your first place as it's inexpensive to replace.