2005 Corolla Verso 2.0 D4D Heating Fault

[tomwhiteley]

Hi guys after some advise on my wifes corolla verso 2.0 d4d. It has a strange issue with the heating. Once upto temperature the heater will not blow warm air until going over approx 40MPH and then its fine. As soon as you drop below 40MPH the air will blow cold again. I have had the thermomstat replaced and this has made no difference. Any ideas would be much appreciated??

Thanks

[gug]

the thing i might point at first is the condition of your water, ie if its really rusted you could have a partially blocked heater matrix also check the water pump it may be worn and not pushing the force it should