C5 - Harsh mechanical sound when pulling off in 1ST gear?

[Jeff]

I did ask a little while ago about this, someone said it was rear engine mount problem. (too much play?)

It does not happen in any other gear, the noise sounds like my gear box is straining badly and worryingly, the noise is getting very regular and louder....and aways happens when pulling off up a gradient from standstill.

Is it definitely the rear engine mount and am I damaging anything by driving the car as it is? Also how much of a job is it to change, part cost, labour time etc.

[Peter.N.]

If it doesn't happen pulling away on the flat without to much throttle it's likely an engine/gearbox mounting. The reverse torque on the engine is at its greatest in 1st gear so is twisting it more than in any other gear.

Peter

[Jeff]

Thanks Peter, I have tried what you said and have noticed difference on level ground, less noise when pulling off gently.

Does there need to be a lot of movement in the engine mountings to cause this problem? ............ as when i was under the car doing brake cables a couple of weeks back I moved the engine and the rear engine mount did not appear to be too bad, just a little movement pretty much as you'd expect. Or is it another mount?

[Peter.N.]

If the mounting is in a poor state itdoesn't need much movement to in effect 'short circuit' it, in other words to give you metal to metal contact. If the mountings are the same most other XUD derivitives it will likely be the top mounting by the header tank that is the problem.

Peter

[xf1ref]

Reviving this old post because I think I'm having the same issue.
Car is C5 , manual gearbox with RHH engine, 163hp.
The sound is more evident in 1st gear but when is cold I hear the sound also in second and third. No sound in reverse.
Is like a clunck when pressing the clutch pedal to change the gear from 1st to second and it's on the front right side (lds reservoir side).
I checked if there is any play on front right side suspension but nothing and also the gear stick is not moving when moving from standstill.
It is possible to be the rear engine mount?

[Peter.N.]

As I wrote somewhat earlier (not that I remember doing it) it is likely to be an engine mounting but could also be the exhaust coming into contact with something when the engine moves. Try moving the exhaust about, it will need some effort as the mountings are quite stiff. If it is a mounting there should be some indication of movement, try levering them with a tyre lever or something similar.

Peter

[GiveMeABreak]

If the clunk is when you pull off or go over a speed bump sometimes, it may be the pivot support clunking where the bush needs replacing. See the second part of my post here:

viewtopic.php?p=592172#p592172

The sound can be replicated but needs a lot of effort to move it back and forth when the car is off the ground on a lift. With the car on the road - all that weight of the car when starting off and harsh braking causes it to slide back and forth making that clunk. At least you can rule this in or out as a possibility.

[xf1ref]

Thanks Peter and Marc for quick reply.

I'm also thinking that could be something else because the sound disappear after driving 30minutes and the engine is at normal temperature.

The clunk sound is absent when pulling off or over speed bumps.
Strange is that the sound is appearing between changing 1st gear to second gear 2. Is not when engaging the clutch in 1st gear from standstill but can be heard when I press the clutch pedal to change to second gear...like when releasing the engine from the load.

[GiveMeABreak]

So won't be what I suggested then as this is a clear pivot bush issue and very distinct when pulling away and under harsh breaking.

[xf1ref]

I tested today with the automatic release of the handbrake deactivated and the engine cold (if this matters). I tried several times with 1st gear and reverse. The sound appear only while trying to move the car in the 1st gear and only for first 4 times.
Until it gets worse I will live with this and maybe it will reveal somehow.

[xf1ref]

Found that the top engine mounts are guilty for that sound.

[Peter.N.]

The rubbers go soft and allow the metal parts to meet.

Peter

[xf1ref]

The anti torque one is not broken but the rubber is very soft, as Perter mentioned. The hydraulic one I think it was affected because I feel some strange vibrations, so I ordered both.