renault espace 2.2 diesel heater cold?

could be a few things,stuck thermostat,water pump,air lock,blocked heater matrix,faulty heater control valve,do you have plenty a/freeze in the systema?a lot of motors freezing up at the moment,would make sure your thermostat is opening,feel the top hose for circulation,is the radiator warming up across its surface?feel the two heater hoses to the matrix,are they getting hot?if they are hot to the control valve it may be faulty,look in the reservoir,give the motor a rev.and see if the water pump is circulating the coolant,jst some things to check out,good luck

cdc
December 2010