Z3 Serpentine belts

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Al323i
Posts: 181
Joined: Wed Nov 15, 2006 8:38 am

Z3 Serpentine belts

Post by Al323i »

I need help on changing the serpentine belts on my 98 2.8L (M52) Z3. The AC belt tensioner (hydraulic) has the 8mm Allen hole in the pulley shaft (cut and dry removal), but the main tensioner (mechanical) does not have the 8mm hole nor the 17mm hex boss nut to put a wrench on. Perhaps because of the tight conditions, I am not seeing the 17mm boss nut (I am sure that there is no hole in the pulley’s shaft bolt), is it 100% that there is one? Other than cutting the belt, is there another way to remove the tension to get the main belt off?

-Al

victory1auto
Posts: 643
Joined: Wed Nov 10, 2004 1:37 pm

Post by victory1auto »

I have never seen on an M5X motor, a mechanical tensioner with no provision to release it. Try looking with a mirror for the 17-mm hex.

If there is no provision for release, I would cut the belt as you suggest, and then replace the tensioner with an aftermarket mechanical unit. These should have the 17-mm hex.

The tensioner should be held to the motor with two 8-mm bolts [13-mm hex].

If you in fact have a tensioner with no release provision, please take a photo of it.

The same tensioner is listed for M5X motors starting in 1991 and going right thru 2006, regardless of what chassis the motor is in.

Al323i
Posts: 181
Joined: Wed Nov 15, 2006 8:38 am

Post by Al323i »

Vic,

Thanks for the response. Because of the poor visibility, I physically felt the whole movable surface for a raised nut, and found none. From the pictures that I have seen, it should be a pretty darn noticeable 'bump'. I can't image that there is no facility to release the tension, but who knows how many mechanics played with this car and replaced parts with low end Asian parts.


Al

Al323i
Posts: 181
Joined: Wed Nov 15, 2006 8:38 am

Post by Al323i »

Vic,

By using an inspection mirror, I noticed that instead of the Allen hole as a tension release mechanism, there was a 16mm headed bolt for the pulley shaft. Job done! Thanks for your advise.

Al

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