M30 engine - strange bearing noise

[simon-york]

Hi guys, wonder if anyone here can help.

I have the M30 engine in my 1988 E34, but it is in 3 litre form rather than 3.5. On the back is bolted a 5 speed manual box and the car has just turned 158,000 miles.

Recently, and this is more noticeable when cold, there is a strange bearing noise that is heard most in first gear and seems to be engine-speed related; a sort of harsh bearing noise as the car pulls away from rest and slowing down as you take your foot off the gas and change gear to second. When the engine is hot it seems to be far less noticeable and is also there whether or not the clutch pedal is depressed.

I am thinking about possibly the clutch release bearing and I know the box has some noisy bearings which are due to be replaced shortly. But in my experience both clutch release bearings and gearbox bearing noise will cease as soon as the clutch pedal is depressed - which makes me think more engine-related. I know noises are difficult to guess at a distance, but does anyone have any thoughts?

Thanks in advance for any views.

[632 Regal]

your engine doesnt have ball bearing type bearings so I would venture to guess a throwout bearing or the very front bearing on the trans behind the clutch/pressureplate.

[simon-york]

Jeff

Many thanks - it does make this noise though as you rev the engine (a little!) with the clutch depressed and 'box in neutral and is definitely engine-speed related. Ought a gearbox bearing not to become stationary? Or could it still be a noisy cluct release bearing even with the pedal depressed?

Many thanks once again.

Simon

[632 Regal]

could be the clutch bearing, is there any way you can get closer to the noise to better isolate it?