Hi. Coolant loss but no leaks found. No heater even with water in system. Done about 70000 miles so due belt and pump. This is an electronic activated pump and the shroud over the pump impeller was seized. Fitted new pump thinking that that this is the fault. Which in a way it was. Still no heater but water loss ok now. Did some research and came upon that vw put a bag of silicate in the expansion tank. This is to help reduce corrosion on the engine. Special anti freeze is used with silicate in it but it can weaken,hence the bag in tank. Unfortunately this bag can break and leak silicate causing pump failure and blockage in radiators. Word has it that even high pressure flush does not cure. Heard horror stories that engine and rads are being replaced. WTF. anyone out there come across this. Don’t really know where to go from here. Hope this is posted to right forum. Regards. Les

Remember when the old Rover K series engine head gasket failed it use to turn the coolant & oil to a congealed jelly which was nay on impossible to remove!