Oil Pump

[ScottyWM]

How difficult is an oil pump replacement on the E34/M50tu? I've searched but not found anything like a write up - hopefully because it's so easy. I've just noticed a bad knocking at start up. This is not the usual knock for the first couple seconds after starting. It has (twice now) had a much louder more pronounced knocking when started that lasted maybe 20-30 seconds, and then went away. Once I was able to open the hood and listen and it seemed to come from both the back of the engine and the front (vanos maybe)? But I really couldn't pin point it. Drives normally, of course I wouldn't drive it while it was doing this. Do you think it might just be the loose bolt issue that I've read about?

Do I need a write-up to do the repair? How expensive is this repair at an indy? (I'm getting too old to do something like this without a lift :) )

I'm very close to replacing the car after having it for 15-16 years. But I do want to pass it on to some deserving teenager or someone who will appreciate it. So I would like to fix this before I seize it up.

TIA...

[genphreak]

Check she don't have loose spark plugs.

They sound like that and will shut up once the head warms, so pretty quickly. Oil pumps, tough they do wear out are not a common issue on BMW engines. Are you running 50 grade oil (eg 20W50)?

Lower viscosity oils can drain from the pump overnight and take some time to recharge (and will cause severe wear within the pump whilst it fills).

Many people think lower viscosity oils are a good idea, but a worn pump means pulling the pan and a day or two of pain if you are organised about the job.

[ScottyWM]

I'll check, but both times it did it, the engine was already completely warmed up.

[genphreak]

I'll check, but both times it did it, the engine was already completely warmed up. Indeed, costs zip to see if they're tight. The gaskets are one-time use, so if removed before they may back out on their own at some point. Usually causes droplets of oil to spit up under the top cover and burn very gradually on the exhausts.

[632 Regal]

Scotty, make sure the oil is compatable with the temperature you are in now. Not to sound stupid but it can play a factor. NC is similar to my area so regular synthetic would do. Personally I would use a 10W50 but I have a 530V* so that may be a factor. If she is hounding at fire up you are running dry sitting there, either too thin of oil or worn bearings. I can't guess because it could be either. Replacing bearings isn't hard but to get the correct ones takes a bit of time to check and log each cylinder and the main bearings.

My guess would be that someone previous of you ran dry and cooked the bearings a bit, not too big a deal but a big deal if you dont want to deal with it.