No Heat

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Hi all,

I have a 1991 Ford Taurus with almost 200K miles that is still running well so I use it for my commuter car. Recently, I have noticed my heater/defroster does not generate any heat at all. The heater fan simply blows normal air. I replaced the heater core less than a year ago and it worked fine until just recently. I have also replaced the water pump and radiator recently so I know for a fact the thermostat is working correctly, and the radiator has the proper amount of anti-freeze. Does anyone have any suggestions of how to troubleshoot this problem? Where can I start looking to find the cause of the lack of heat?

-thanks in advance-

posted by  stevehord

A little more information may be in order here: this is a 3.0 L, 6-cylinder, has had a new heater core installed within the past 12 months, a new radiator installed two days ago, a new water pump installed two weeks ago. The temperature normally fluctuates in the normal range from just below half to just above half - in the normal range.
The temperature and heater controls are simply knobs turned to the correct setting (cold on the left - warm on the right) and (defrost, mix, floor, off, vent, norm a/c, max a/c) respectively. When I switch to defrost, mix, or floor and turn the temperature all the way to the right - after the car has reached normal operating temperature - and then turn the fan on, any speed; all I feel is cool air coming from all of the vents. The air conditioner works well, by the way.
Does anyone have any ideas what might be the problem? I don't know where else to look.

Thanks again,
Steve Hord

posted by  stevehord

Steve, sounds like you have an air pocket stuck in your heater core...it's very common on those cars because the heater core sits high than the radiator. Many mechanics simply leave the radiator cap off with the engine running to "burp" out any air bubbles...but this doesn't work well on the taurus. What you may need to do is...disconnect both heater hoses(from the engine, not firewall) and proceed to fill one of them with coolant...watch for coolant to start flowing out of the other hose...by doing this you force the air pockets out of the heater core. Now, reconnect the heater hoses and make sure the radiator is topped off, leave the rad cap off and run the engine...the coolant should start to over flow as the engine warms up. Should take about 10-15 minutes, if the coolant level in the radiator does NOT drop abruptly(whether it be 1 inch or you can't see any coolant) then you know you have all the air pockets out of the system and you can re-cap the radiator and let the car continue to run to make sure the coolant temp stays steady in the "normal" range. While running the car keep the heater on so you can see if you're getting heat or not(have the heat on even when you have the rad. cap off). If you do it right, you should have some good heat.

*You should start to get some heat before you re-cap the radiator, if not, let the car run with the rad cap off until you start getting some heat-make sure temp gauge isn't pegging and electric fan is coming on*

posted by  Sick88Tbird

aahhh, sounds like a plan to me. Thanks for the informaiton - I will get this done tomorrow after work. I went by the Chilton manual for the coolant bleeding when I finished replacing the radiator and I'll bet there must still be an air pocket in there, as you say. Again, thanks for the information.

posted by  stevehord

Just glad I could be of assistance...I'm not saying that I'm 120% sure that's your problem but from what I've experienced with tauruses, that sounds like the exact same problem I've seen. It's very common for those air pockets form in the heater core...good luck with it! Please let me know what happens.

posted by  Sick88Tbird

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