Auxiliary belt tensioner.

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Brian4
Joined: Mon 19 Dec, 2011 19:02
Posts: 541

  Z3 roadster 3.0i
Location: Hinckley

Auxiliary belt tensioner.

Post by Brian4 »

Our engine had developed an annoying rattle which I only ever noticed when idling and warm. Bit of investigating later I worked out it was the tensioner pulley for the auxiliary drive belt. I changed the belt a while back but the tensioner seemed ok but should have followed best practice at the time. Anyway thought I could just change the pulley, as in Mike's article in Straight 6, but no the pulleys available are for the hydraulic tensioner and that is a different shape to my spring one. Finally bought the hydraulic tensioner and not convinced it would fit and low and behold the fixing positions are already on the block so was a straight swop.

One of the suppliers did have a spring tensioner for the aircon belt but this has the pulley in a different position to the aux belt.

Comparison of spring and hydraulic tensioners. The spring is held with 2 bolts and the hydraulic has 3 bolts.

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Brian
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2000 E36/7 Z3 3.0i
2016 F31 335d
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Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2093

  Z3 roadster 2.8
Location: Daglan, France

Re: Auxiliary belt tensioner.

Post by Mike Fishwick »

The spring-type tensioner looks to be identical to that used on a Mk 4 Golf TDI etc - it would be worth checking with German & Swedish to see if the pulley is the same size - or close - to the BMW one. There is enough latitude in the tensioner to enable a slightly different size of pulley to be used.
A Z3 is not just for Christmas - it's for life!
Mr Silver
Joined: Wed 25 Feb, 2009 09:34
Posts: 360

  Z3 roadster 3.0i

Re: Auxiliary belt tensioner.

Post by Mr Silver »

A gentle reminder that if you are about to upgrade to the later hydraulic belt tensioner above you will require the long M10x150mm bolt (not supplied with the tensioner). Best to have this to hand before you start taking things apart.
OEM part no. B07.11.9.904.677 from your dealer. This is for M54 engine, yours may be different.

Ask dealer for the other bolt and washer if required.

From a general service point of view It might be a good opportunity to replace the top alternator bolt at this time too (simple job). There is a history of difficulty in removing this bolt when you have problems (especially on Sundays during snow storms et. al.).

Hope this helps

Regards.
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