[hawks05]

i could be wrong but im pretty sure that even if the theromstat is closed the coolant should be getting to the heater core other wise major pressure would be building up in a system that doesnt allow any flow yet the water pump us pumping especially when you first start driving and it hasnt open up and you are going say 35mph. also another way to just check to see if the themostat is working right you should notice flow in the radiator once the car gets up to normal running temp.

 

[hawks05]

true but im just saying that i believe the delivery to the heater core is a by-pass so that when the thermostat isnt open the coolant still moves just not through the radiator. now if your not getting heat when you turn on the heat then your heater core is mostlikely blocked. i mean there could even be a slight chance that your water pump is messed up too.

 

[hawks05]

you never know sometimes theres weak spots in the metal. im not saying your wrong first things first got to see if anything is flowing and the easiest way to do that is watch the radiator with the cap off. if not check the thermostat if not that then it would be the water pump. if not that then the radiator itself could also be blocked if the car is over heating. i had that problem at about 100,000 miles and put in a new radiator and bam it was back to normal.