car heater not working to well how to i check heater matrix?

c5 2.0hdi heater only works full speed

asif
November 2009

and you might have an airlock in the cooling system

steve
February 2005

Does the engine warm up to running temp?, if it takes a long! time if it does it is probly your thermostat it could be locked open, run the engine from cold and FEEL the top pipe, there should be no water running through it at first untill it warms up.
If it warms up O.k (eliminating termostat) and your coolant level is O.k then it could either be your heater matrix is getting blocked or a weak water pump,

steve
February 2005

Before you go and do that take a look to ensure that your coolant level is correct. If you have insufficient water in the system the heater wont work effectively.

Mike
September 2004