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    vanos whine noise

    Hi everyone,

    I've recently got my e30 running with an m50TU, and I'm slowly ironing out all the kinks. One of the main issues I'm having trouble with is a loud whining/rubbing noise coming from the front of the engine at lower rpms (sub 3500). When the car is cold, the motor seems to bog until 3500-4000 rpm (as though the brakes are being applied then released). I don't have the Vanos "rattle" but I'm led to believe the Vanos isn't functioning properly.

    Initially I thought it was a misaligned serpentine belt, but the engine made the same noise without the belt installed, specifically from the top of the motor where the Vanos unit sits.

    The m50 I'm using has a Dr. Vanos stage 1 unit that was installed about 4 years ago, and ran fine, but it was pulled in favor of an s52, so the motor had sat for 3 years until now. I've put close to 500 miles on the motor and the noise doesn't seem to show signs of going away.

    I performed the stomp test and don't have any check codes pertaining the the Vanos. Has anyone had a refurbished Vanos unit go bad on them? I find it unlikely, but not out the question. I've tried flushing the motor, but no success.

    If anyone has any suggestions how to get rid of this noise, I'm all ears!

    Thanks,

    Joey

    #2
    No bites?

    I called Dr. Vanos and he had said the Vanos Units typically don't go bad. This weekend I'm going to swap a confirmed working solenoid and check the upper chain guide/tensior for any unusual wear. Otherwise I think the Vanos unit will have to be replaced as the car doesn't seem to pull as smooth as it should since there's a noticeable hesistation. A M50 isn't fast, but something is still off

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      #3
      Well I pulled the valve cover this weekend to check for anything unusual, and nothing looked out of the ordinary (chain guides, tensioner, etc.). I did an oil change to flush everything since the first few hundred miles of the swap and the noise still persists.

      Anyone have any suggestions before I buy another new Vanos unit?

      Comment


        #4
        Originally posted by mtech325 View Post
        No bites?

        I called Dr. Vanos and he had said the Vanos Units typically don't go bad. This weekend I'm going to swap a confirmed working solenoid and check the upper chain guide/tension for any unusual wear. Otherwise I think the Vanos unit will have to be replaced as the car doesn't seem to pull as smooth as it should since there's a noticeable hesistation. A M50 isn't fast, but something is still off
        That would've been my recommendation...
        I'd take the VC off, and turn the engine by hand to see if there's any sign of slack or hesitation in the chain.
        (but re-reading your post, sounds like you've already done just that)

        You've checked/ cleaned the check-valve/ piston & spring assembly behind the Vanos solenoid?

        Have you checked compression across the cylinders?
        I doubt a faulty piston-ring could be causing the the noise or symptoms you describe, but I figured it's already a case of grasping at straws, so....

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          #5
          I pulled the solenoid off and checked everything behind it, but didn't notice anything out of the ordinary. I tried a spare solenoid as well and no dice. A compression test wouldn't be a bad idea at this point. Like you said, grasping at straws...

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            #6
            Well I'm probably going to bring this to the shop next week and have them look at the car as I'm stumped. As a recap, the noise IS NOT caused by:

            -serpentine belt
            -Vanos Solenoid
            -visibile debris in the valvtrain
            -used/dirty oil

            Here's a quick video I made. You'll have to listen closely, but you can hear the whine/hum in the background. Maybe this noise is similar to a problem someone else has had before.

            https://www.youtube.com/watch?v=kFrbNULh-hc

            The car drives fine otherwise, but this noise is so annoying to listen to while driving at low RPMS...

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