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

Seems to be an up and coming problem on these.Very likely the heater matrix is all sludged up from the silicate.It will need to be replaced.

Try to disconnect heater pipes in at bulkhead flush with a garden hose connected to lower pipe on matrix and it may flush out the silicate in reverse flow.

Hi. Customer took to VW who changed the heater rad and flushed the system. He was hoping for a goodwill. Cost him £540. Two weeks later heater not working again and rad again blocked. The story continues. Merry Christmas. Les

Get the sludgy coolant analysed!

Modern engine oils & coolants seem to react badly together nowadays!

Slight head gasket oil gallery weep by possibly?

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!