Weird grinding/rattling .....

[AndyH]

ok guys bare with me on this one...gonna try and explain the problem as best as possible. have tried the search as i know its been mentioned albeit rarely in the past.

my car seems to have a grinding/mettalic rattling coming from the engine bay. it happens at very low level in all gears i think but is extremely loud when at half/full throttle in 4th and 5th (sort of buils up from around 2k - 2800k very loud) seems to disappear after this but hard to tell if its there at low level.
i have found that if you dip the clutch when the noise is present the noise disappears completely.

the car doesnt lose power or slip or anything like youd expect from the usual clutch slip. all gears engage fine apart from sometimes first thing in the morning when its cold etc.

i have had the car up on axle stands and run the car up and the noise doesnt seem to be there at all (and its quite unmissable at the revs/gears stated above) i know the cars not under load in this situation but it was the only thing i could do to try and find the noise etc. a rolling road would be ideal i suppose as its simulating the wheels being on the road etc but that means forking out loads and the hassle of trying to exlplain what im trying to do to the garage etc

i have removed the two heatshields on the manifold just incase but the fact that the noise disappears when the clutch is disengaged makes me think its not a heat shield rattle etc.


please help guys.................................

 

[Vtec6000]

hmm, sounds clutch or gearbox related. Does it happen if revving the car or only when moving? I would say check the clutch release bearing first. Hopefully its only that as anything within the gearbox i.e main shaft bearing will be expensive to fix.

 

[AndyH]

ye only happens when in gear. not while idling or when rev'd while in neutral etc.
as i said though..it didnt happen when run up in gear on axle stands

 

[Vtec6000]

ye only happens when in gear. not while idling or when rev'd while in neutral etc.
as i said though..it didnt happen when run up in gear on axle stands

Probably because there is no load on anything when on axel stands. Check your driveshafts first but after that your going to need to remove the gearbox to check clutch, flywheel and gearbox internals if clutch/flywheel doesn't show anything.