Hunt the clunk

Yesterday evening I went round to my friend Aaron’s house so we could fit new lower ball joints to Neddy, having replaced the upper ones previously. In case I hadn’t already said elsewhere, Neddy has been making a rather disconcerting clunking noise when accelerating, and I had thought it was the upper ball joint, but replacing it made no difference. So Aaron and I did the lower ones too. And did it make any difference? Not a sausage.

It’s kind of a hard noise to describe really, especially since we’re not entirely sure where the noise is coming from. You can hear it when inside the car, but not really from outside because of the noise from the engine. This leads us to suspect that it’s not to do with the suspension or anything on the sides of the car, as you would expect to be able to hear something like that form outside. It’s a sound akin to clicking your knuckles, and happens when pulling away from stationary, or accelerating hard in first or second gear. It sort of clicks three or four times before settling down.

I did a good deal of searching and reading up on The Mini Forum last night, trying to find out if anyone else had come across the same problem, and it seems that clunking noises are quite common in Minis and can be the result of all sorts of problems. By far the most common is worn engine stabaliser bushes, causing the engine to rock in the engine bay, hitting metal against metal ever so slightly when applying torque. Now, I have three engine stabalisers fitted: the top one has been uprated to poly bushes, the standard bottom one has new rubber bushes, and I’ve fitted an extra bottom stabaliser bar from the engine block to the subframe. I would be surprised if it was a stabaliser bush that had gone, since they’ve all been seen to relatively recently. That said, it’s not beyond the realms of possibility that the top one has gone again – poly bushes are great but apparently because they are harder they can sometimes wear out more quickly.

Other possible causes include CV joints, wheel bearings, track rod ends, steering rack, gear linkage, suspension cone, exhaust, subframe mounts, tower mounts. I have to say, from the descriptions people have been giving, none of those sound particularly likely, or at least not as likely as the engine mounts. I shall have to take a closer look at the top engine steady and make sure that hasn’t perished – it’s a nightmare to do anything with because of all the gubbins in the way. To tighten the bolt you have to get at it from the top and bottom of the car, with one long extension bar from above (having removed the air filter and other gubbins so you can get to it) and one very long extension from below (lying underneath the car and getting someone else to guide the end to the nut). Last time I did this with Billy’s help, in the dark, and it took us a couple of hours just to replace two bushes, so I’m not looking forward to doing that again…

Still, for now I’m more or less satisfied that the car is safe to drive around, in that I’m confident that because all the ball joints have been done that the wheels aren’t likely to fall off. And if it does turn out to be the engine stabaliser, at least we know we’ve done it before, so we should be able to do it again!

Other things that need doing at some point include: replacing the headlight bulbs, which are getting rather dim; sorting out the battery (don’t think it’s holding its charge); tightening the fan belt (possibly related to the battery charge problem); sorting out the rust on the bottom of both doors, under the headlights, under the wheelarch; replacing the wheel arches, as I don’t like the black plastic trim that comes as standard; replacing the rocker cover gasket; having the engine properly tuned, which would involve having the ECU remapped to take into account the RC-40 exhaust and K&N air filter; replacing the front brake discs and pads, and possibly fitting braided brake hoses; giving the engine a jolly good clean; washing and polishing the car; replacing track rod ends and possibly tie bars too. So, lots to keep me busy then! Donations to the cause are of course very welcome…

One thought on “Hunt the clunk

  1. Well, I’ve had a quick drive, and it does feel a bit like the engine is moving slightly, suggesting it may well be an engine stabaliser issue. In fact, I managed to dab the accelerator and saw the top of the engine moving slightly, so it looks like I’m going to have to replace the top engine steady bushes again. Grrr. Might go for normal rubber ones this time, see if they last longer than the poly bushes.

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