Engine Whine

carl2990 · Post by **carl2990** » Sat Sep 17, 2016 11:58 am

Hello,

So I've had my 57 Z4 3.0si for around 3 months now and love it! Found a few issues but nothing to be unexpected for a 9 year old car, bushes and bearings etc.? It only has 47500 miles on the clock so not high milage!

One problem which I'm struggling to diagnose is the newly developed whine, I think it's coming from the alternator.

https://vimeo.com/183101862

Here's a recording of the noise. It seems similar to this.

https://youtu.be/72REiFhvNuE.

Is it worth just replacing the voltage rectifier (and the bearings whilst I'm at it) to see if that's the issue?

Cheers!
Carl

GuidoK · Post by **GuidoK** » Sat Sep 17, 2016 2:31 pm

The rectifier wont make that noise. No need to replace that if it's still ok imho.

First check if its the alternator at all I think. Maybe with an stethoscope (thats probably my favorite tool for these kinds of things)

Smartbear · Post by **Smartbear** » Sat Sep 17, 2016 4:40 pm

That could be a noisy pulley wheel the auxiliary belt runs on, as mentioned check it out with a listening stick/stethoscope

Rob

carl2990 · Post by **carl2990** » Sat Sep 17, 2016 6:13 pm

It did seem strange that an electrical component would produce a mechanical whine!

Cheers for the help, I'm going to have a closer look tomorrow

carl2990 · Post by **carl2990** » Sun Sep 18, 2016 1:31 pm

So I've had more of a look around today and still can't figure it out.

Next step is take the serpentine belt off and check all the pulleys. They don't look excessively loose as i've seen in other videos. I was planning to do this myself today but after taking the cover off the top of the radiator/fan, the pulleys aren't the easiest thing to get access to!

Two more videos here...

https://vimeo.com/183187362

https://vimeo.com/183187362

carl2990 · Post by **carl2990** » Fri Dec 02, 2016 4:48 pm

Still haven't figured this one out! The alternator clutch has been replaced and it's still making the noise. I don't think it's the tensioner pulley as the belt isn't jumping around and it's not coming from that area, the alternator clutch wasn't too worn either.

It's definitely coming from the alternator or engine oil filter housing area, putting a screwdriver against the metal there amplifies the sound.

Any ideas?

z4pilot · Post by **z4pilot** » Fri Dec 02, 2016 5:26 pm

Have you read this thread? It's dealing with a similar problem and may give you some additional clues.

viewtopic.php?f=3&t=84702&p=1265016&hil ... e#p1265016

Smartbear · Post by **Smartbear** » Fri Dec 02, 2016 5:28 pm

Hi, I've heard of collapsed oil filters causing noise-its only a cheap item so change it & have another listen

Rob

Whaleykenny1 · Post by **Whaleykenny1** » Wed Jan 02, 2019 3:32 pm

I can’t thank you enough. It was close to oil change time (bmw intervals) but I had to use a stp filter last time bc I was sent the wrong one and had to get 1 from Autozone. I’d decided it was my alternator and started pricing before reading your post. Sure enough, I changed the filter and noise disappeared. It has certainly collapsed. Thanks again

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