My car has developed an odd noise. Someone I spoke with mentioned it might be my serpentine belt tensioner/s. The noise occurs no matter whether the car is hot or cold.

It occurs when the rpms are around 1000 and you are letting the clutch out from a dead stop and the rpms dip down for a second. It will also do it when you rev the engine in nuetral too, from 1000-1200 rpms.

It seems to come from the front of the engine, so I doubt it is clutch chatter. It performs perfectly and quietly when the rpms are above 1200.

Could this be the tensioners for the belts? What parts should be replaced and should I get them from the stealer or bimmerparts.com?

BTW, the belts are shot and the car has 55,000 miles.

Thanks!
Matt

Belts are cheap and easy to replace ($30-$40 for 2)....

but at 55k miles...tensioners could also use replacing...not so cheap at around $50 each. You need 2. AC side and Alt/PS. side. If you are on a budget, do the Alt/PS side as that belt does A LOT of work.

Thanks for the info :) Have you heard of bad tensioners causing this type of noise?

Yeah, I personally think from a design/performance point of view, the use of tensioners verus the old "nut and bolt tension" method sucks!

The tensioners are wound up springs pushing AGAINST the belt to keep it tight...problem is...springs wear out...

So as the tensioners age...they loose that push...and you get some serious belt noise...

Sucks.

I was thinking about rigging the traditional nut/bolt tensioner set-up...not much room though...

Yes, the belt tensioners dry out or something. And causes a lot of noise/squeaks around the drivebelt area.

If you're around 55K miles, I would recommend that you plunk down some $$$ and do most of the maint. items at the same time. For example, I was at 65K miles when my inspection II light came on. I, too, had the same drivebelt noise that I believe you're describing.

I ended up swapping out the radiator, thermostat, thermo. housing, water pump, belts, tensioners and the pulleys.

Now is also a good chance to scratch the performance itch because you can upgrade to underdrive pullies! and if you do, you'll obviously need different belts than stock.

good luck,
Eddie