Noise/rumble when clutch pedal is out.

[NielsGalan]

Hey people.

Car makes a rumbling/rattling noise. It comes from underneath the car and is only audible (from inside the car, that is) when I roll down the window. The interesting bit is, that then I press in and hold the clutch the noise disappears. Comes back when I release the clutch again.

I've noticed this when car has been idling and standing still.

Any clues?

[whiskychaser]

Hey people.

Car makes a rumbling/rattling noise. It comes from underneath the car and is only audible (from inside the car, that is) when I roll down the window. The interesting bit is, that then I press in and hold the clutch the noise disappears. Comes back when I release the clutch again.

I've noticed this when car has been idling and standing still.

Any clues?
Sounds like the clutch release bearing/arm. Worth checking the adjustment but if its working fine I wouldnt worry. Eventually you will need a new clutch but so will everybody with a manual:)

[wjbell]

Yeah, sounds like the throwout bearing is going bad.

[NovceGuru]

For what its worth- I had a similar issue with my e30 and it turned out to be a wasted exhaust hanger arm.

[BMWCCA1]

It could be normal gear rattle. Throw-out/release bearings usually make noise with the pedal depressed where the bearing is actually being used, or spin-down when released. If it's worse warm than cold it's likely "normal". Have you owned the car for a long time and never heard it, or is it new? What tranny fluid are you using? BMWs have done this since the lightweight transmissions came out in around 1983 and even an attempt with dual-mass flywheels didn't kill the gear rattle. You should hear what their bike trannies sound like at idle with clutch out and no bodywork to hide the racket!

[bsell]

It could be normal gear rattle. Throw-out/release bearings usually make noise with the pedal depressed where the bearing is actually being used, or spin-down when released. If it's worse warm than cold it's likely "normal". Have you owned the car for a long time and never heard it, or is it new? What tranny fluid are you using? BMWs have done this since the lightweight transmissions came out in around 1983 and even an attempt with dual-mass flywheels didn't kill the gear rattle. You should hear what their bike trannies sound like at idle with clutch out and no bodywork to hide the racket!

I'm with you on this one. The other suggestion of an exhaust hangar is interesting and a cheap and easy look-see. I would find a lift that lifts the car by the wheels and check things out with a 'clutch pedal-buddy'.

I wondered about a tired pilot bearing but these act up with the clutch disengaged as the pilot bearing supports the flywheel-end of the tranny input shaft with the pressure plate disengaged.

I thought about the input shaft bearings but the OP is not complaining about noise under acceleration. This bearing tends to get beaten up when snapping shifts (typically when trying to scratch the tires going into second gear;) ) and usually howls like the dickens when the engine is making good power.

So find a lift and see what is happening. Hopefully you haven't sprung a leak in your tranny and are running around without lubrication.

Brian

[Barney Paull-Edwards]

As with another thread on the same subject, release bearing but in your case if the noise goes when you press the pedal then your flywheel is on the way out,Porsches have the same problem with a damper/bimetallic flywheel,Winfred had a rant a while ago about them!

[bsell]

As with another thread on the same subject, release bearing but in your case if the noise goes when you press the pedal then your flywheel is on the way out,Porsches have the same problem with a damper/bimetallic flywheel,Winfred had a rant a while ago about them!

Are you talking about the rubber-damped clutch disc? What an expensive for the owner-way to quiet the tranny chatter! A couple too many heat/cool cycles from slipping the clutch and snap goes the rubber damper. Can you say instant clutch job?:(

Did BMW use this same design on the 5 series?

Brian