About Josh Fields Expertise I can answer questions related to the BMW e30. These are the cars produced from 1984-1991 (1992 for convertable) in the United states. I am more fluent with the six cylinder models, although few things changed for the 4 cylinder cars. I know most of the problematic areas of these cars, and have found ways to fix them.
Experience I have owned six different E30's over the last 10 years. I do all my own work, and know about ever nut and bolt on these cars.
Question My 1991 6cyl 320i is noisy all the time, idle thru to driving. It's what I would describe as "rattly or clattery" and yet I have done the valves twice with no change. I am inclined to think it's coming from the transmission underneath, is this a possibility? (Yes there is fluid in it!).
Answer Larry,
Unfortunately these are loud engines. Even in tip-top shape they make a rattle/clicking noise. This noise is in the valves and injectors.
You can quiet it down some by running a little thicker oil. Of course this depends on where you live. You cant run a really thick oil in the winter if you live in Maine or some other really cold state. You can try to adjust the valves .01" tighter and that might help, but I think you are going to have to live with it. These are 12 valve engines and they have no hydraulic devices to dampen the valve train. So any play (even in spec) between the rocker arm and the valve spring will cause a ticking noise. There have been constant questions about this on E30 forums.