Originally Posted by wpoll

Good point about the oil pressure light/switch - maybe the DME is killing the ignition because of the low oil pressure indication.

Maybe somewhere with more knowledge on your specific engine can chip in here (I'm an oil-burner!) but as a first step, try disconnecting the battery for 5-10 mins then reconnect it as see what happens. Seems a reset like this can clear a few common errors hat appear after a vehicle has been worked on.

Actually just got the battery put in it before starting.

In fact, I'm at the point where I'll be disconnecting the battery when I'm doing anything that requires the disconnection of any electrical connector on these Beemers - the DME/DDE and other modules are too darn clever...

If the reset doesn't work for you, then it might be time to look at the actual oil pressure. Something blocking some oil line somewhere? When you say you change the seals on the oil cooler you mean the auto-trans fluid cooler right? The one on the lower corner of the radiator? I will look over the diagrams for your car (2001 4.4i right?) and see if I can see where you might have a blockage...