COOLING SYSTEM AIRLOCKS: How do I get rid of an engine cooling system airlock?
This is for an engine that does not have separate air bleed screws.
Start from cold.
First switch the heater to maximum heat to make sure the valve to the heater matrix is fully open.
Next remove the expansion tank pressure cap.
Start the engine and leave on idle.
As the engine heats up, very carefully (TAKING GREAT CARE NOT TO TRAP CLOTHING OR FINGERS IN AN ENGINE PART AND REMEMBERING THAT THE ELECTRIC FAN COULD START SUDDENLY)gently squeeze the top and bottom hoses.
Continue after the thermostat opens until the engine starts to overheat and the fan starts.
Then replace the expansion tank cap.
Drive the car round the block at normal speed.
When you get home, leave the engine running and VERY SLOWLY AND CAREFULLY AND USING A BIG RAG OR TOWEL, release the expansion tank pressurecap just enough to let any air out, but close it cagain before coolant comes out.
With a bit of luck, that should get rid of the airlock.
