Heater works fine for about 30 minutes then runs cool

As the subject says the heater in my 2001 P38a runs funie for about 30 minutes then starts to blow cool air into the vehicle. The TestBook sysmbol is not showing in the display and otherwise the system runis fine.

Also, the pollen filters are fine.


Any ideas?


Thanks


Paul

PVKD,

I assume your coolant level is ok? Our '99 would blow warm under load but when idling (or cruising down a hill) it became cold. We had a bad head gasket and had leaked enough coolant to affect the flow through the heater core.

Just a thought

Greg Haugen

Yes, the coolant level is OK and the thermostat was changed sometime again by the dealer and believed to be working correctly.

Thanks