Two years ago, the then nearly five year-old belts on my E36
would be pretty noisy on cold mornings, for a few minutes. The belts
still looked pretty good, but I replaced them with new ones 1½ years
ago. Last winter, no noise on cold mornings, but this year, the noise
is back. These belts are only 18 months old and have probably only
about 15K miles on them. These things shouldn't be whining already
should they? They still look practically brand new.
If you used belts from the local car parts store then you will have these
problems. I have heard that the belt cross section on European belts are a bit
different from ours and the difference causes these problems.
I am basing this on what I hear often on the Audiworld forms.
They recommend buying from your friendly audi stealer.
The belt tensioners have bearings in them:
I'd advise to take the belt off at night, then spin the tensioners, water
pump, A/C pulley and water pump in the morning when it's cold. That will
isolate the noisy component.
I hope this helps?
There is no belt tension "adjustment" on BMW E36 engines. There are
automatic belt tensioners for both the Alternator-Waterpump-Power
steering belt and also the AC belt.
I have seen one where the mechanical tensioner developed a "set" (a
detent) from engine vibration while sitting in the same place all the
This made it hang up so that it would not apply the correct tension once
it reached the detent. Replacing the belt would temporarily alieve the
problem until the new belt stretched to the same length as the old one
and the tensioner reached the detent.
I'm betting that this is what is wrong with yours. To check it you can
remove the belt and exercise the tensioner throughout its full range of
motion. It should be smooth, with no detents, hangs or bumps. If not
fully smooth, replace it (they aren't that expensive) and you should be
able to put back the current belt. It should be fine.
Belts should not make any noise even as they become worn. They should
just get to the point where they noiselessly fall apart. That's why we
replace them prophylactically. Belt squeel would indicate either a
tensioning problem or possibly that one of the driven devices is binding.
Yes, spring tension. There are two types. One that has a little
mini-shock absorber looking spring assembly and one that has a torsion
type spring assembly. You'd have to look up your car to see whaich you
have. And yes, either way it is possible for them to go bad.
Dunno about BMW. FWIW, on the Alfa 2000 GTV I had back in the 70s, there
was an oil pressure operated chain tensioner. I think there was also some
kind of ratchet arrangement to keep the tension, once it had been adjusted.
This might due to:
An idler pulley or a water pump bearing's grease drying up. I've found the
same problem on many cars, and localized it to the idler pulley in most
cases but, the water pump in some cases.
The new belt just ran the bearing at a higher pre-load and got the grease
moving a bit.
I hope this helps?
Check your alternator mounting bushings. They've probably deteriorated by now.
You'll keep chasing loose belts until you replace them.
If you do it yourself, the polyurethane replacements are far easier to press in,
and work just as well as the rubber.
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