Heater malfunction

[bonnietiler750]

I use the car all year round and this week...cold...The Heater comes on fine and quickly, however I have noticed when stuck in traffic and even when the temp nicely just below the middle the heater suddenly goes cold, I turn it off turn off the blowers and it returns to normal, do I have a problem here

[mallardstag]

I use the car all year round and this week...cold...The Heater comes on fine and quickly, however I have noticed when stuck in traffic and even when the temp nicely just below the middle the heater suddenly goes cold, I turn it off turn off the blowers and it returns to normal, do I have a problem here

Have you checked your coolant level and eliminated all the air?

[LAMBRETTLAD]

Water pump ?

[Lingen]

I suspect the fault may be an electrical one. If the engine temperature is correct the water pump must be working ok.. Perhaps the heat you are getting is from the ram air when the car is in motion, and the fan isn't working properly, so it all goes cold when you stop.
Mike.