Mysterious Noise

[shalmaneser 26]

A new noise has made itself known amongst the cacophony.

 

It only happens once the engine is up to temperature, and is a whirring sound that sends vibrations through the car - although the engine is on stiff mounts so that's always going to happen. I suspect it's something clutch related as the noise seems to go away once you put your foot on the clutch.

 

Can anyone confirm this is the case, or come up with an alternative diagnosis? I know it's a nightmare diagnosing a sound via a forum post but it's got to be worth a try.

 

I had considered that it may be the gearbox, but they seem reliable by-and-large, and there certainly isn't any whining, and the gears are nice and direct (for a BE gearbox, that is...!) with no crunching at all.

 

For some reason I've mentally decided it's the release bearing? Does that sound about right?

 

If it is the clutch I'll replace the clutch and speedo cable while I'm down there, am i missing anything?

[welshpug 1,657]

sounds like gearbox bearings, clutches tend to rattle in the off position and still rumble if the bearing is dry when the pedal is held down.

[shalmaneser 26]

Hmm, that's not ideal, and way of confirming this is the case?

 

Guess the best move is to replace the box if the bearings really have gone.

[Anthony 1,003]

Does the whinning change at all with either engine speed or road speed? Does it do it when stationary, or only when moving?

[shalmaneser 26]

Does the whinning change at all with either engine speed or road speed? Does it do it when stationary, or only when moving?

 

Only when moving, stays the same despite speed as far as I can say...may have to do some more testing.

 

Edit: it's not constant but happens periodically for a few seconds and goes away. It does happen more the longer you drive it...

Edited October 9, 2010 by shalmaneser

[2-Pugs 57]

Sounds like gearbox or perhaps driveshaft or wheel bearing to me. Doubt it'd be the clutch, as it doesn't contact anything that would cause it to make a noise like that.

[JoshGti 8]

Whirring could be friction, especially at hotter temps. Is the gearbox full of oil?? or empty? As welshpug said, if it was release bearing they rattle around on the shaft, not whine.

[shalmaneser 26]

Whirring could be friction, especially at hotter temps. Is the gearbox full of oil?? or empty? As welshpug said, if it was release bearing they rattle around on the shaft, not whine.

 

Gearbox is full up, changed the oil a little while ago while replacing the seals. Used generic Castorl oil (was the correct spec from the owners manual though!) so might change that to the dealer spec stuff.

 

I went for a drive yesterday and nearly convinced myself that the noise changes when changing direction; I'm praying this is the case as changing the wheel bearing is hugely more preferable than fiddling around with the gearbox...Will get it on axle stands soon and have a real good poke around.

[shalmaneser 26]

Got her on stands today to swap the cracked manifold for an uncracked one. Utter arse of a job, but got everything off in the end, just need to get the gaskets from Pug in the morning along with a handful of nuts and bolts.

 

annoyingly hubs seem to be in fine condition, given that I changed the bearings only a few months ago it would seem unlikely that they would have given up. Going to put in some dealer spec gearbox oil (and change the engine oil while I'm at it), will see if the new fluid makes any difference.

 

Just massively hope I'm not flogging a dead horse on this one, it's had a new manifold, oil, filter, cambelt and waterpump and gearbox oil, would be a shame if I have to dump the lot - if the gearbox really is on it's way out I'll definitely do and engine conversion, so all the money put into the 8V will have been wasted...