Article by: Paul Axford
Applies to: All models with the M30 big six engine WITHOUT the self-leveling LAD system (this article was written with a 730i).
You could do a “one-person flush” the way I did it in the photo with the engine running and a lot of excitement, but there is an easier way that does not involve having to drink a gallon of apple juice or risk the threat of an embarrassing oil spill.
It turns out that you do not need to run the engine to pump ATF through a conventional PS system – simply turning the steering wheel will do it just as effectively. So based on this knowledge, here is an easier method:
a) Raise the front end on jack stands to get the front wheels mostly off the ground.
b) Cover the left engine mount with a rag to keep oil from spilling on it.
c) Disconnect the PS return hose (that is, not the one that goes to the pump) from the reservoir and extend it into an empty container to catch the waste oil. Use a half meter (20″) of 12.5mm (1/2″) OD vinyl hose or similar. Naturally you will have to deal with some oil spillage at this point.
d) Plug the open fitting on the base of the reservoir with a short piece of 1/2″ ID tube plugged at one end.
e) Open the reservoir cap and turn the steering wheel once lock-to-lock (which will empty the reservoir.) Refill and repeat until you see clean oil returning to the waste container.
f) Re-attach the return hose and top off reservoir to the correct level.
g) Clean up the huge mess you made doing this.
BMW models with the LAD “self leveling” system do not use ATF, but rather a synthetic mineral oil under the brand name Pentosin CHF:
If ATF is added to a system designed for Pentosin, the seals in the self leveling rear shocks will be damaged and the system will not function. This is an expensive and time consuming repair.
~ M. Oswald