2012 astra cdti heater problem

[Brooky1310]

Hope someone can help iv got a 2012 astra 1.7 cdti.the heater in the car only blows warm when im driving but on tickover it goes cold iv changed the thermostat with oem but original 1 worked fine the bottom hose coming from the water pump gets hot but the pipe coming out of the radiator to the thermostat is cold anyone had similar issues

[GreenV8S]

Brooky1310 said:

on tickover it goes cold

That suggests there is very little or no coolant flow through the heater at tickover. Is this one of the engines with a plastic impeller that breaks up?

[Brooky1310]

Thanks for the reply iv had car on a ramp today and its leaking water from the water pump so hoping a new pump sorts it out