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    Whirring Engine Noise on M50

    Hi all. I've got a new issue with my 93 525i Touring. I'm hearing a whirring noise coming from the engine and it seems to be coming from the head somewhere... It gets higher and lower in pitch with engine speed. If I keep the car in park or neutral it happens as well. Would that eliminate the tranny as a culprit?

    I took off all the accessory belts and it's still there. Any ideas on what would cause this? VANOS? Cams? Something else?
    My 325iX DIY Threads:

    Front Wheel Bearing Replacement

    325iX Rear Subframe Bushings and MUCH more w/pics!

    325iX Steering Rack Replacement, Suspension, & Oil Pan job w/pics!



    #2
    Bueller?
    My 325iX DIY Threads:

    Front Wheel Bearing Replacement

    325iX Rear Subframe Bushings and MUCH more w/pics!

    325iX Steering Rack Replacement, Suspension, & Oil Pan job w/pics!


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      #3
      My thought is vanos or timing chains...hard to saw without hearing it

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        #4
        Most likely the vanos, mine has a slight vanos rattle that settles into a steady sound when the engine is warm.

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          #5
          Thing is, it's not a rattle at all. And now my car is bogging down and hesitating.

          My plan is to probe around with a stethoscope this weekend to hone in on the source of the noise. But it really seems to be coming from the intake... Very strange.

          I'll get a recording of it and post up soon.

          Thanks for the replies!
          My 325iX DIY Threads:

          Front Wheel Bearing Replacement

          325iX Rear Subframe Bushings and MUCH more w/pics!

          325iX Steering Rack Replacement, Suspension, & Oil Pan job w/pics!


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            #6
            clutch fan?
            Originally posted by priapism
            My girl don't know shit, but she bakes a mean cupcake.
            Originally posted by shameson
            Usually it's best not to know how much money you have into your e30

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              #7
              Originally posted by Northern View Post
              clutch fan?
              No. I took that off...
              My 325iX DIY Threads:

              Front Wheel Bearing Replacement

              325iX Rear Subframe Bushings and MUCH more w/pics!

              325iX Steering Rack Replacement, Suspension, & Oil Pan job w/pics!


              Comment


                #8
                Any update on this?

                Does it seem to change withe electrical load?

                I have the same issue and i am leaning towards the alt, might rebuild it and see what happens.
                "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery." - Winston Churchill

                "People sleep peacefully in their beds at night only because rough men stand ready to do violence on their behalf" -George Orwell

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                  #9
                  how about a large intake leak at the head? rushing air can make all kinds of noises and could certainly cause hesitation. you should be able to pinpoint the sound better with a make-shift stethoscope. or buy one at the store for $5

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                    #10
                    Already vacuum checked, all new seals when the intake was off for the coolant sensor as well.

                    One thing that has me pointing to vanos is that i was playing with oils and found that my m50 likes 5w40 syn over everything else. The whirling sound changed with oil weight as well.

                    Incase nobody knew BMW now has 0w20 or 30 in the overhead oil system in all the dealerships and it is up to the tech to choose your oil weight now.
                    "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery." - Winston Churchill

                    "People sleep peacefully in their beds at night only because rough men stand ready to do violence on their behalf" -George Orwell

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                      #11
                      Alternator, idler pulleys, and water pump starting to fail would be the first things I'd look at. Possibly also the AC compressor clutch bearing failing. If you pull both belts and run it(briefly, so you don't overheat it), you should be able to isolate all of these.

                      VANOS usually rattles rather than whirring. I'm not really sure what would make a whirring noise in that system, as it's pretty simple.

                      Timing chain guides would be my internal bet. Known for failing eventually, and as they rub against the chains, there is definitely potential for them to make noise.

                      Very uncommon, but an issue mine had when I got it, was a failed thrust bearing on the intake cam. It only made a little noise though, surprisingly.




                      Project M42 Turbo

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                        #12
                        I forgot to follow up on this. It was my clutch fan afterall. Northern was right!
                        The bearing seized and caused the fan to spin a full speed all the time. And it was out of balance causing the car to vibrate a lot. I guess when I took it off to test the sound I was hearing was normal engine noise - kind of a bonehead move on my part.

                        Dennis at OMG Motorworks actually spotted the problem in like two seconds. Swapped in a new fan and all is good again.
                        My 325iX DIY Threads:

                        Front Wheel Bearing Replacement

                        325iX Rear Subframe Bushings and MUCH more w/pics!

                        325iX Steering Rack Replacement, Suspension, & Oil Pan job w/pics!


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