Hi, others may have a different method, but I find this works, remove the cap from the expansion tank, select full heat on the heater, start the engine and let it run at a high idle for 15~20 mins, then stop the engine, put the cap back on the expansion tank, run the engine for 10~15 mins, switch off and let it cool down then carefully remove the cap on the tank and top up as required
nigel
August 2008