518 Engine Rattle

Hi Lads,

I have a 1995 518 that has a top end rattle above 2000 rpm and is more prominent on the over run, Just bought it today with 98000 miles, runs great apart from this rattle. any ideas anyone?

thanks Roy

If it's camshaft then not really.

Only real solution is change camshaft/ hydraulic followers etc.

Try http://www.eurocarparts.com for prices. Usually not too bad.

Probably best to get a garage to listen to noise first, as I am guessing; not having heard it.

Basically, no.

If it is the big end bearings, then yes. It would entail removing the sump, and then undoing the con rod bolts and very carefully sliding the old bearing shells out and sliding the new ones in. Trouble is if it has a rattlr/ knock it could well have already damaged the crank journal surface, meaning it will need a regrind and a set of undersize shells.

If it is main bearings, then it is an engine out job, as you will need to move the crank out of the way to replace the bearings. However, the same applies; the damage may already have been done, and putting a new set of bearings in may even make it worse.

I have to say I'm not that familiar with the BMW 4 cylinder units really, but it might be worth making sure that things like the crankshaft pulley are done up tight. If it has had a cam belt done recently it could just be that the pulley has a bit of movement in it. To be honest though that is possibly a little optimistic.

I'd assumed you had the belt driven M40, but you must have the chain driven M43 then.

It could be a chain problem. If the chain tensioner is weak or the guides are worn then it could certainly create a rattle, and it would probably be louder on the overrun as the chain is not under as much stress, and so can move that little bit more.