Sorry folks I keep posting bits in the What have you done to your car today thread about this and should have started my own thread long ago. So my TDi has been loosing coolant in varying amounts over the last few months. Recent culprits have been a split hose (replaced) knackered radiator (replaced) and I’ve also changed parts to rule other bits out, first the coolant reservoir valve cap and then whole new reservoir itself. This has stopped the amount lost (from refilling every day!to every week) but it’s still not right. Currently I’m getting the coolant alarm going off, wait for temp to drop, open the cap and WHOOSH it fill back up. All this time the engine has never overheated stayed at 90 Just now I’ve noticed something new... had heater on driving home and noticed it blew cool air when stood in traffic/idle. As soon as I set off again it was face melting. Any ideas what this could be pointing to?