I had this same thing scare me one time, took it to my now non existent independent BMW shop, & he pulled the valve cover, looked things over, put a screwdriver against the timing chain sprocket, to kind of pull or push on it, & one or two of the bolts were loose. Can't remember any more details than he probably put a new lockplate under the bolts & maybe some loctite on the threads, & I was out of there in 10 minutes. Could also be broken timing chain guide, tensioner not working properly.
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2002 owner since 1980

Thanks for the responses. I think I will go ahead and get my car back from them and try and get some help from a couple local 02 guys I know if I can't figure it out on my own.

Do tell, what happened? I have a similar situation. Engine has 6000 miles on pretty complete rebuild and a sudden onset of knocking/cladder. Vacuum shows a little flutter but not huge so can't tell if it's timing chain or sudden valve sickness. I am looking at your problem as a place to start w/ my own.

my noise which I thought was a timing chain turned out to be a really lose oil chain. So you can pop off the oil pan and have a look down there -- especially if the timing chain *seems* tight.

But first take the timing chain tensioner out and make sure the spring is OK.

I will add that to the week end diagnostic session. In your case did the noise start abruptly? Mine was as if a hose became disconnected and dropped into the fan, and yes I have checked for disconnected hoses in the fan and have found none, sadly.

OK, no bad dizzy advance weights. All valves look good tho not checked (noise was so sudden can't imagine one just went South), compression all w/in 125-128. Timing chain tensioner ok, chain nice and firm. Can't pinpoint noise but not at base of oil pump--where filter is threaded on. What gives??

daved. wrote:

I will add that to the week end diagnostic session. In your case did the noise start abruptly? Mine was as if a hose became disconnected and dropped into the fan, and yes I have checked for disconnected hoses in the fan and have found none, sadly.

No this engine has always had the noise. This is a car I got from an auction so I don't know the history of it. It just was a tick tick tick noise that didn't sound good, and I decided it wasn't the valve or anything else till I took off the oil pan and the chain was really slack.

It could be that the PO changed the oil pump and didn't shim it well.. the pump looks like someone had been messsing with it.

So what about your water pump? Maybe its making a clattering. You can pull the fan belt and start the car and if the sound goes away you know it could be that. Naturally you don't want to run too long .. just long enough to see if the noise is there.

Its a quick test -- a hell of a lot easier than pulling the oil pan!!