Rattling noise

[Dunk]

Having worked through a variety of problems with my 96P E320 (61k miles) in the past six months (new boot due to rusting around lock, air conditioning failure, head gasket and half moon gasket replaced) the car has now developed a loud "rattling" noise when idling in gear - the noise disappears when power is applied.  The problem only occurs when the car has been on longish journeys.

Any thoughts?

 

[black180]

Sell it.
(Edited by black180 at 10:56 am on July 17, 2002)


(Edited by black180 at 10:56 am on July 17, 2002)

 

[Arnie]

Hi,

It usually takes at while for the gearbox oil to warm up and thin, so probably that it why you notice it more after a long drive. Could be one of the gears (I presume it's an Auto, if not could be a clutch layshaft), but it may also be a totally unrelated resonance, since when the engine is hot, it will tend to idle at slighly lower RPMs, and this could excite a resonance in a broken exhaust or soemthing like that. You'd need to try to pinpoint the source of the rattles.

 

[dave elcome]

Arnie.

Pleae enlighten us all, What is a clutch layshaft?? never heard of one.

 

[altreed]

Hmm, I have noticed that my exhaust is noticeably louder when driving in the wet, so the exhaust could be the culprit!

Dave
Silver c36 '69k '97p

 

[Arnie]

dave,

..sorry, I should have said gearbox layshaft, or input shaft, driven by the clutch..


BTW:
some time ago BMW had a "problem" with its manual gearboxes being a bit rattly when the engine was idling in neutral gear, after a long drive. This was due to the input shaft and layshaft rotating in very thin oil, without much damping. Other than the annoying noise, it was not however, a real problem to the gearbox, as the oil still did its job, but was cured by specifying a higher viscosity oil.


(Edited by Arnie at 7:12 pm on July 18, 2002)

 

[white190]

I suspect Arnie's right
Its most probably the input shaft or the exhuast..
This also used to be a problem with Ford motors where owners would change the gearbox oil for a lower viscosity to try and get better power or easyier shifting ..but then complained of rattling gearboxes after a few miles... If this is the problem you will want to change the oil now.. so the bearings dont get worn too much...thats asuming its a manual gearbox.

If it's an auto your pretty much stuck with the fliud recomended by the manufacturer ... still worth changing the fluild for new stuff... but rarely cures the problem...
Most of the old Ford Granadas Auto's that developed this were either left rattly or had gearbox recon.

I hope for your sake its the exhaust.... although hopefully not the Cat (they can develope nasty rattles as they die) as this would aslo be V expensive.

 

[john]

Start at the beginning and then work your way to worst case scenario.
Get the thing up on ramps and have a good look round and see where the noise is coming from.
Having had a few motors and more than a few probs - always keep your sanity by approaching problems from the cheapest option first point of view

 

[Koolvin]

could be your catylitic convertor