Reply to thread

Message: <blockquote data-quote="zib" data-source="post: 704610" data-attributes="member: 23925">There are a few possible issues related to this. Please check the following:1) Air in the system either by cracked hose or air leaks into the system. Get a pressure test done. But the obvious tell tale sign is the loss of coolant inside the expansion tank. Did you check the coolant level?2) If 1) above is not the cause then it could be a failing thermostat. Get it replaced.3) It could also be that the high speed fans are faulty either the relays are shot or the high speed temp sensor switch has malfunctioned. The only solution is to replace them.But I think this is quite unlikely as it runs when the temp is high which what it is supposed to do.Btw these issues can be easily resolved by any reputable BMW garage. These are also DIY if you have plenty of time and proper tools provided you have properly diagnosed and know the root cause.Get the parts required and have the ready before attempting the repair.</blockquote>