How to fill coolant

[crankin]

I have replaced the water pump on my 90 735iL. Where do you fill the cooling system? I hope its not thru the overfill container. That would take awhile.
Thanks

[Kalevera]

Steve, open the bleeder screw at the top of the thermostat cover (directly above the engine fan), then fill the system from the expansion tank. I don't see why it should take a while? It's much more efficient than most of the stupid crap I see on other cars. Fill until coolant comes out of the bleed screw, then close it, continue filling until the expansion tank hits the cold level. Start the car, turn heat to full, open the rad cap again and rev the engine (you'll need two people if the car has EML because there's no throttle linkage to manipulate when leaning over the engine). Things are good when there's a steady stream of coolant from the return line during revving, which exits right through the top of the cap, there's heat in the cabin, and no bubbles out of the bleed screw (crack it open a time or two if there's no coolant returning to the expansion tank/also when the car is warm to expel any air that might be stuck there). It's common for the passage to clog and cause the car to overheat (search "pisser" on the forum).

Also, it's a good idea to use BMW OEM coolant, some substitute mercedes/saab/Zerex G48 equivalents, but I personally wouldn't stick anything but the OEM stuff in my cars.

best, whit

[crankin]

Great. Thanks, as usual, whit.