Draining and Filling Coolant

Cooling system, bleeding

Air may become trapped in the cooling system during filling. Trapped air can prevent proper coolant circulation. Whenever the coolant is drained and filled, the system should be bled of trapped air.

NOTE: All M60 engines and M70 engines from 8/89 (1990 model year) are equipped with a coolant equalizer hose from thermostat housing to radiator. These models lack a coolant bleeder screw

- Add coolant to expansion tank until level reaches COLD mark on tank.






On M30 engine: Loosen bleeder screw (arrow) on thermostat housing.

- Add coolant to expansion tank until it spills from screw. Tighten screw.






On early M70 engine: Loosen bleeder screw on thermostat housing.

Add coolant to expansion tank until it spills from screw.
Tighten screw.
Set temperature controls in passenger compartment to full warm and start engine.
With engine idling at normal operating temperature, loosen bleeder screw.
Tighten screw when coolant spilling from bleeder is tree from air bubbles.

- After engine has cooled, recheck coolant level and add coolant as necessary.

CAUTION Always use genuine BMW coolant or its equivalent to avoid the formation of harmful clogging deposits in the cooilng system. Use of other anti-freeze solutions may be harmful to the cooling system.