Hi Guys,

I have a 2009 T-Jet, it seems to take an age to heat up in the mornings and also i can be driving for an hour get hot air from the blowers at about half an hour in , then all of sudden it will switch back to cold air again. the blowers are working fine ( just blowing cold air ) the heated rear window seems to work OK.

any ideas?

Cheers

Chris

Thermostat?

I'd suggest that maybe the thermostat is stuck open.
Not such a bad thing until winter comes along.

stat, air lock water pump, coolant level and or frozen coolant

The interior heater is fed direct from the head, before the thermostat, so it's operation will have no influence.

IMO, only random pockets of air in the cooling system will generate periods of cold airflow from the heater vents (assuming you've not got climate control and the sensors are screwed up and randomly moving the mixer flap), either caused by a very low coolant level (rads are known for leaking) or a possible headgasket issue.