2.0tdci ST Car has covered 50k.  Strange one here, I know these have a habit of the water pump impeller spinning on the pump shaft requiring a new pump. The problem I’m having is the car is heating up and heaters working fine but the small pipe  going to the coolant tank, from the thermostat there is nothing coming out of it and the coolant tank staying cold. Normally I’d say the pump, but the heaters are working fine, so pump must be working?

before I check and take the terribly designed, prone to breaking, plastic pipe off from the stat to the coolant tank to check for a blockage, is there any other issues known on these to cause no flow through return pipe?

Have you got some sort of engine overheating problem ?

The small pipe in to the top of the expansion tank is for when the coolant expands as the engine gets hot. Given that you have a modern diesel engine and the ambient temperature is only around the 3^oC these days there will be minimum flow, unless the engine gets super hot.

9 hours ago, unofix said:

Have you got some sort of engine overheating problem ?

The small pipe in to the top of the expansion tank is for when the coolant expands as the engine gets hot. Given that you have a modern diesel engine and the ambient temperature is only around the 3^oC these days there will be minimum flow, unless the engine gets super hot.

Doesn't overheat, no pressure in the header tank, just no flow on the pipe. Which a lot of people say it is the water pump if so. As you say, it could just be the weather.

Just to update, coolant return pipe was blocked. Blew it out with an airline and its flowing now, ordered both of them new from ford £45 for the pair.