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gbrownings

auxiliary (serpentine) tension belt - advice please

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Hi, apparently the above needs replacing and it is my call if I want the various associated parts (tensioner/adjusting pulley) replaced as well. Makes it a much more expensive job and no evidence that this is critical. Any views on whether I should replace the lot? 

 

It is the belt that connects to the AC. I am going to buy the parts. Am correct that is is OeM  11287833266   https://www.realoem.com/bmw/enUS/showparts?id=DE92-EUR---E39-BMW-M5&diagId=11_2656#11281407520.

 

grateful for any advice.

 

 

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I went through this last summer.

 

Thought I would replace both belts, pulley assemblies/pulleys and both tensioners. Only replaced the actual pulleys and most of those were OK but changed them since they were quite cheap. Which leads me on to.....the pulleys are available as separate units. The OE supplier is Schaeffler, whose brands include INA, FAG and Ruville among others.

 

Schaeffler web catalogue: https://webcat.schaeffler.com/web/schaeffler/en_GB/index.xhtml?reset=1

 

There's a whole load of stuff on M5board about the correct size of these pulleys - do a search there.

 

The pulleys that came off had INA and BMW branding (..hazy memory) so was happy putting INA replacements back on. The pulleys were about £10 each and they simply unbolt from the supporting pulley assemblies, though one was a bit of a fight. The tensioners themselves were fine so I left them on and I still have the new ones in their original packaging looking at me now.

 

The OE belts are Contitech and are available at reasonable cost outside the dealer network.

 

Spin the pulleys and check for roughness; compress the tensioners and check for sufficient resistance to compression. Note that the tensioners are installed in a particular orientation - they're marked with an arrow indicating 'top' (up).

 

Doesn't have to be expensive at all. You might get away with just replacing the belt but I'd be tempted to change the pulleys because 'you're already in there' even though they're fine and spin without roughness.

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Thanks very much. Very helpful. 

 

I think I will get get the belt and take a view once the garage are able to examine the condition of the pulleys etc.

 

They seemed to think there was some sort of 'kit' I could buy that came with all the necessary bits but I haven't been able to find anything online.   

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I guess it depends on how worn the components are. As DepthHoar said, check the wear and if it isn't perished you can get around with replacing a few pulleys.  I did a preventative front end rebuild at 75k for piece of mind, but for some reason have a very minor chirp on cold start still.  

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9 minutes ago, ER said:

I guess it depends on how worn the components are. As DepthHoar said, check the wear and if it isn't perished you can get around with replacing a few pulleys.  I did a preventative front end rebuild at 75k for piece of mind, but for some reason have a very minor chirp on cold start still.  

 

Thanks. I took it to the garage as the car has developed a bit of a high pitched whine which increases as the revs go up. It's not 100 per cent definite the tensioner is the cause as the noise is quite hard to locate but as it has done 100k miles, it seems a good place to start and reasonably cheap for elimination purposes. 

Edited by gbrownings

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I see, these things are difficult to diagnose without hearing it...  may be worthwhile checking oil filter housing mounts.. especially if the whine is oscillating with increased revs and can be heard or felt from the interior whilst driving .. drove me nuts for a while ... could not pin point the cause of it, until I found that to be the culprit with a stethoscope..I bought aftermarket ones for a few quid, then genuine ones - it helped but something was there... finally, after reading some posts on the M5Board, ended up removing one of the two all together and never heard it since...

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 Had the old ones lying around so some part numbers and dimensions for replacement pulleys referred to in the above postings:

 

*All the pulleys in the photos are the old factory-fitted originals. The boxes they appear with in the photos contained the new INA replacements*

 

A/C pulley first:- (INA markings just visible on the original factory-fitted pulley.)

 

P1090870comp.thumb.JPG.112cce8f7a47a552cca1e9771ba0db79.JPG

 

P1090871comp.thumb.JPG.800b753fd258ce5dcfb38ab9c4ed1f96.JPG

(Above) The INA new replacement is 24.5mm wide but as you can see from the wear marks in photo above the 1.5mm deficit isn't an issue as the belt has plenty of 'elbow room'.

 

P1090872comp.thumb.JPG.1b8ca7bcdabf116ecfdf06cf0773d531.JPG

 

 

 

Water pump/alternator pulleys:-

P1090873comp.thumb.JPG.e06c8f2f529d791d9f5fd69ed8070464.JPG

 

P1090876comp.thumb.JPG.a465fad290c227b846997dbadd264d46.JPG

 

P1090875comp.thumb.JPG.964444c53327769cca3ab5db032654bd.JPG

(Above) Both of the water pump/alternator pulleys.

 

Bore size for all pulleys is 17mm.

 

Hope this helps someone tracking down replacement pulleys. Much cheaper than the BMW complete assemblies!

 

 

 

Edited by DepthHoar

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1 hour ago, ER said:

I see, these things are difficult to diagnose without hearing it...  may be worthwhile checking oil filter housing mounts.. especially if the whine is oscillating with increased revs and can be heard or felt from the interior whilst driving .. drove me nuts for a while ... could not pin point the cause of it, until I found that to be the culprit with a stethoscope..I bought aftermarket ones for a few quid, then genuine ones - it helped but something was there... finally, after reading some posts on the M5Board, ended up removing one of the two all together and never heard it since...

 

Thanks. Will mention this to the garage. It sounds a bit like an alternator whine or turbo whistle noise (which it obviously isn't!)

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