No Heat

[greg allen]

I have check all the simple items. No blocks, both hoses hot. How can I tell if it is the heater core or the blend door? I am going to remove the acuator to seen if that is moving properly.



TIA

 

[greg allen]

2002 sporttrac

 

[user 64972]

Had an issue with this a few years nback on my wife's Monte Carlo and it was the theromstst.

 

[greg allen]

How can you tell if is the theromstat?

 

[scott degroot]

Does the air temp change at all when you switch between hot and cold. Even with a bad thermostat there should be a noticeable difference in temp. If you have no change in temp at all then find the temp blend door actuator adn cycle the setting from hot to cold adn see if the actuator moves.

 

[John G]

Well, I just have to reply to this thread



If the thermostat is stuck in the open position, the coolant will not get hot, and the temp gauge will remain cold.

http://www.ehow.com/list_7606570_symptoms-thermostat-stuck-open.html



If it is stuck in the closed position, the engine will overheat, and the temp gauge will go sky high (this happened to my SportTrac).

 

[mike burns 3]

You have a engine temp gauge. If it is approx in the middle and you still have no heat the problem is not related to the thermostat. Thats not necessarily a good thing as it gets harder to identify the problem from there.

 

[greg allen]

Thanks for the responses



The blend door motor is ok. The blend door is ok. Coolant is good. Flushed out both hoses. Water runs through. Top hose is hotter than bottom. Gave up and went to the dealer. Dealer claims it is heater core and wants 1200 to replace it. No leaking in the cabin. No smell. I am wondering how they came to that conclusion? Anyone know what the sign of a bad heater core is?





Happy thanksgiving to my neighbors.

 

[greg allen]

There is no change in temp. When I go from hot to cold.

 

[A1cntrler]

Check your heater control valve. I don't recall where it was at on my '01, but I think it was on pass side close to the firewall. You may have a 2 port one or a 4 port one. Make sure the vacc line is hooked up to it and that it moves when you make your heat selection. Rockauto.com has them for 14 bucks up to 25 bucks depending on which one you want to get. There are also pictures of them so you can get an idea of what you are looking for.



I had to replace the one on my '01 Trac for same reason, and I replaced the one on my '07 because it was leaking.

 

[Mark Price 2]

Your "heater control valve"may be stuck shut. The HCV is located just before the water pump on the core outlet hose.(a lot of vehicles hcv is before the core) So, coolant is basically stagnant all the way from the hcv back through the core to where the coolant originates from near the thermostat. Coolant stays fairly hot just through heat transfer to the core on the inlet hose and a little cooler on the outlet. Something to check anyway before dropping that kind of money. The hcv is vacuum controlled. It closes the flow when set to max a/c or off positions. I'm not sure of causes for a hcv to get stuck closed but I know it does happen. Hope this helps a little. Good luck. Happy Thanksgiving

 

[Mark Price 2]

good call A1cntrler. Seems we were responding at the same timenline:

...that's where it is located on my '03 anyhow

..also, does your temp gauge live in the same area as usual? as MikeVT mentioned

 

[Mark Price 2]

Good info and tips here. Thanks to Mr. ncranchero. Just for anyone else that may need it. Youtube video "How To Install Replace Air Temperature Door Actuator Explorer Mountaineer 98-01 1AAuto.com" (same as Gen 1 ST's. not sure on Gen 2's)

 

[greg allen]

Thanks for the responses. The heater control value, how can I tell if it is stuck? Also how can you tell if the thermostat is gone? thanks