My car (UK turbo MY96) has developed yet another knocking noise.

It appears to be coming from the front left (this doesn't mean that much, as sound travels a long way in a car.) and it is quite loud - like something solid hitting something else solid.

It knocking is most noticable at slow speeds and happens when the wheel is dropped into dips in the road. It doesn't usually happen when the wheel goes over a sharp lump. It doesn't happen every time either...

I've reseated the springs (numerous times) and put on new dampers a while ago - so I don't think it's those... I've also examined all the bushes on the front suspension.

It had a rocker cover leak that I didn't notice for a bit too long - this will have soaked the engine mounts in oil - I doubt they would like that too much...

Also, when the car engine is switched off, the car is vibrated as it stops. I'm sure it didn't do this when I got the car.

I'm running out of ideas now. Does anyone have another suggestion, or is it now a case of throwing money at the problem until it goes away?

 

As said on the other bbs.. check the downpipe to gearbox mount just in case..

Simon

 

Thanks for the reply. Yes - already done that. One of the reasons why I am so confused is that I can't seem to find an obvious cause

 

Look at the anti roll bar drop links. Bushes here wear easily.

Then the steering rack mounts.

And then, the wishbone bushes, which may be worn and knock / clunk when moving sharply before the suspension damper can catch up ... ( replace them with polyurethane bushes for best gain! )

If these are not the source, maybe the CV joints on driveshafts .. expensive ( near £300 a side!!! - search on here for other options )

 

If engine mounts then replace with STi items, far better / stiffer, and look at the anti rock rod under the intercooler in case it has worn and allows engine to rock!

 

Thanks for the reply.

Rollbar droplinks are done already.
Not done the wishbone bushes yet, but they do look OK. But then again, so do the engine mounts...

Worryingly, there is some play in the driveshafts at the gearbox splines. (Not twist, but up and down - hope this makes sense!!)
This would explain the knocking, but not the engine vibration.
(I planned on the group N mounts anyway - I think they're the same as the STI items, and they're 1/2 the price of the dealer sold items. )

The CV joints look OK too. It was the first thing I suspected, so I peeled the boots back, had a look and regreased them.

 

have had a similar problem.
top mount damper was unscreewed

 

beryllium, that the in line bar from engine to bulk head? That;s what I meant by the engine anti rock rod .. forgot it's real name ... can get uprated oned from USA for circa £50.

DNB - Does sound like engine mounts then, with the vibration on stopping.
Possible gearbox mounts too.

As you say, the Group N / STi ones are far far better, and cheaper!

 

beryllium - have had an unscrewed damper top mount before - very similar noise, but I don't think it is it this time.

Oh well, better let the moths from the wallet (again)