205 engine vibration

[Ian Campbell]

I have a 1990 205 GLD 235K Miles. Owned car since it was 6 months old, regularly serviced. Just started severe vibration when sitting ticking over, changed all engine mounts, N/S driveshaft and crank pulley. No difference at all, engine is running sweet as a nut and starts on the button. Running out of ideas??

[CitroJim]

is there any difference in vibration levels if you depress the clutch?

[Ian Campbell]

is there any difference in vibration levels if you depress the clutch?

No its just the same if the clutch is in or out, vibration is there when the engine is ticking over.

[MattBLancs]

Is the engine vibrating, jiggling on its (new) mounts? Or just noise hear in the cabin? (If cabin noise then wonder if something rubbing/catching on the bonnet (e.g. exhaust)

If engine seems to be the source, suggest engine stethoscope/ long screwdriver/ piece of wood or cane = have a listen around the engine bay and see if can pin point the noise.

Note if listening like this for the first time can be a whole orchestra of unusual noises fed into your ear - many of which can be completely normal! E.g alternator bearing roar, injectors make very severe "clack!" Etc, so it's worth doing the same trick on a few engines to train your ear somewhat!

Matt

[Ian Campbell]

Thanks Matt, the engine is sitting on its new mounts just fine, not jiggling about whatsoever. I've just to replace the small Bush that goes in the end of the fork on the rear engine mount, other than that they're all done. I've taken the alternator belt off whilst running the engine but no difference. One thing I haven't checked is that all the subframe bolts are tight. It's definitely worse when sitting in the car but when outside you'd think it's all good.

[CitroJim]

Is there any smoke at idle and/or on a quick acceleration from idle? I'm thinking, having excluded so much else, you have an injector that's giving a poor spray pattern at idle and causing vibration through poor combustion on that one cylinder...

If this is the case then there's likely to be a little smoke as a result of the poor combustion...

[Ian Campbell]

Thanks Jim, no smoke at all, everything seems to be as it always has been, just running a treat.

[CitroJim]

Thanks Jim, no smoke at all, everything seems to be as it always has been, just running a treat.

That's got me well baffled Ian! I'd need to see and feel it before diagnosing further... I'll be both watching with interest and will keep on thinking about this one... I must admit I woke up in the middle of the night thinking about it!

[Ian Campbell]

Lol, yes it's a strange one, the new bush for the rear engine mount has arrived so I'll get it fitted and check all the subframe bolts etc. Try anf get some sleep

[Ian Campbell]

That's me got to the bottom of the engine vibration. The big round mounting at the lower back of the engine, I've replaced it but I've made sure that it is orientated correctly, the 2 larger parts of the rubber itself have to be vertical, when I first fitted the new mounting I just pressed it in but it was about 90 degrees out and the vibration was still there.

[MattBLancs]

Interesting, thanks for confirming the eventual solution, glad its fixed.

I have cross posted it here:

viewtopic.php?t=72575#p734942

As a similar discussion about engine mounts - and your experiences undermine what I suggested may be an answer to that query.

Matt

[Ian Campbell]

Matt, yes it is interesting that something so small can cause such a problem. I've also noticed that if you look at the rubber part of the mounting only half of it is actually attached to the outer steel part, I suppose this explains why it's to be orientated correctly, it's not a solid rubber all the way round. Thanks for your help.

[MattBLancs]

Matt, yes it is interesting that something so small can cause such a problem. I've also noticed that if you look at the rubber part of the mounting only half of it is actually attached to the outer steel part, I suppose this explains why it's to be orientated correctly, it's not a solid rubber all the way round. Thanks for your help.

Spot on both counts - I too am surprised was such a difference, and yes the mount looks simple but has a couple of different things going on - two pieces of rubber act in shear (at top and bottom of mount, connected to both inner and outer) whilst the other two act individually, just in compression (tension not possible, as you say it's not joined to the outer steel ring)

Glad to be of some help

Matt

[CitroJim]

Excellent Pleased to hear this is now resolved... An interesting one...