Replacing the coolant (BMW 3 Series E30)

The coolant must be replaced as part of the maintenance schedule every 2 years.

Note: If the coolant is drained during repair work, it should be drained into a container, since it has not yet lost its frost-protective and anti-corrosion properties.

Draining the coolant

Disconnect the ground wire from the battery.

Set the heater switch in the passenger compartment to maximum heating power.

When opening the lid, first unscrew it a little to release the pressure. Then completely unscrew and remove the lid.

Caution: When the engine is hot, open the cap carefully. Risk of injury! Place a rag when opening. If possible, open the cap when the coolant temperature is below 90°C.

Remove the plastic cover under the radiator.

Place a clean container under the radiator and unscrew the radiator drain plug "1".



Place a clean container under the engine and unscrew the drain plug "2" on the engine block.



316i models from September 1988 and 318i models from September 1987: If you only need to drain the coolant from the radiator, open the vent plug on the top of the radiator. In this case, you do not need to remove the drain plug on the engine block.

Drain the coolant completely.

Screw the plug with a new gasket onto the engine block and tighten it to a torque of 50 Nm.

Tighten the drain plug on the radiator slightly. To do this, insert a coin into the plug slot and tighten the plug manually.

Filling with coolant

Four-cylinder engine manufactured before August 1988: Fill with coolant to a level 2 cm below the threaded part of the filler neck "1". Leave the filler neck open for now.

Models 316i produced since September 1988 and 318i produced since September 1987: Open vent bolts "1" on thermostat housing and "2" on radiator.



Pour coolant into the expansion tank until the tank is completely full and until coolant free of air bubbles begins to flow out through both vent bolts.



Tighten the ventilation bolts and the expansion tank cap.

Start and warm up the engine at a speed of over 2500 rpm. The air remaining in the cooling system will cause the coolant level to drop to approximately the prescribed mark. A slight excess of the level, approximately up to the 9th rib from the top, is acceptable.



Six-cylinder engine: fill the expansion tank with coolant up to the "K" mark. Close the tank cap.

Connect the ground wire to the battery.

Warm up the engine until the thermostat opens (the lower water hose gets warm). While doing this, give the gas a quick push. Four-cylinder engine manufactured before August 1988: During the warm-up process, you may have to top up the coolant. Finally, close the expansion tank cap.



Six-cylinder engine: bleed the cooling system. To do this, run the engine at approximately 1,500 rpm. Open the bleed screw "E" on the thermostat housing and do not close it until coolant, free of air bubbles, starts to flow out of the screw. Then tighten the screw to 8 Nm.



Check the cooling system for leaks, especially at the plugs and water pump.