Aircon works fine, however I get no hot air.
Any quick tips? how can I check that the coolant flows through the heater core?

 

Does the temp gauge show the engine getting fully warm? It is common on this model for the thermostat to stick open.

Another common problem is failure of the electric coolant pump

Cheers
DD

 

Here's my order-of-precedence:

Thermostat stuck open (renew - don't crack the ears on the housing!)
Heater core clogged (backflush with water/radiator flush)
Coolant pump brushes worn out (renew brushes)
Water valve stuck closed (renew valve)

There are TSB's about the heater core in the large file download area. There is a how-to with pics for flushing the heater core and for replacing the brushes on the coolant pump. I can't recall anyone claiming a failed water valve...which is odd..

 

Thx. Will see first what it could be.
Temp gauge shows a steady 50% reading, certainly not fully hot.

 

50% is about where it runs at proper temp. Also where it runs across a wide range of temps - gauge is not terribly sensitive/precise....Best to get an OBDII adapter and read the temp directly from the ECM. But on the face, sounds like your T-Stat may be ok...if your upper radiator hose is uncomfortably hot to touch, it is not likely your t-stat.