# 2002 325i water pump belt tensioner



## bmwphd (May 31, 2005)

Hi,

I own a 2002 325i with manual transmission. I plan on replacing the A/C (short) and the water pump/power steering pump/alternator (long) belts next year. Since I like to plan ahead, I wanted to see how easy it would be to replace the belts. To have more room I replaced the fan – I was surprised how easy it was.

I identified the nut that needs to be turned CW in order to release the tensioner for the A/C belt. I am having trouble finding the tensioner for the longer belt. It does not look like anything shown in the Bentley manual I have, which covers only the 1999-2001 E46s.

There’s something that looks like a tensioner to the right of- and slightly under the alternator (not the pulley attached to the alternator) but I do not know how to release it. This “tensioner” looks a lot more complicated than the one used for the A/C belt. There’s a hollow cylinder attached to a mechanism that seems to be “turnable” in the CW direction. I can fit a 13 mm socket to the bolt head at the end of the cylinder. I tried to turn the 13 mm bolt CW and the only effect was that the bolt seemed to tighten. I got a bit scared and decided to ask for advice.

Any thoughts? Thanks.

P.S. What is a hydraulic tensioner? Is it possible that the 2002 model uses one of those?


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## titan silber (Jan 12, 2005)

*hydraulic tensioner*

I have a '02 330ci and I think we have the same tensioner device... the belt tension is not applied by a spring but by a hydraulic cylinder. On my car, I had it up on jack stands with the lower cover off looking up from the ground. First I grabbed the belt from below and pulled it and I could see the tensioner moving. Then I looked at how all that adjusting was going on and figured out where a pry bar could be used to wedge the tensioner to give me enough slack to remove the belt. It was a monkey see monkey do kind of thing and now that I have it figured out it is a piece of cake! Just try it and I'm sure you'll figure it out! Regards, titan silber


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## hmr (Jul 28, 2002)

:dunno: 
http://forum.e46fanatics.com/showthread.php?s=&threadid=58872
http://forum.e46fanatics.com/showthread.php?t=257559&highlight=belt


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## bmwphd (May 31, 2005)

*water pump belt tensioner*



titan silber said:


> I have a '02 330ci and I think we have the same tensioner device... the belt tension is not applied by a spring but by a hydraulic cylinder. On my car, I had it up on jack stands with the lower cover off looking up from the ground. First I grabbed the belt from below and pulled it and I could see the tensioner moving. Then I looked at how all that adjusting was going on and figured out where a pry bar could be used to wedge the tensioner to give me enough slack to remove the belt. It was a monkey see monkey do kind of thing and now that I have it figured out it is a piece of cake! Just try it and I'm sure you'll figure it out! Regards, titan silber


Thank you, Sir!


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## bmwphd (May 31, 2005)

*water pump belt tensioner*



hmr said:


> :dunno:
> http://forum.e46fanatics.com/showthread.php?s=&threadid=58872
> http://forum.e46fanatics.com/showthread.php?t=257559&highlight=belt


Thank you for the very useful links, HMR.


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