No heat

have a 99 taurus wagon with a 3.0 liter engine. have changed thermostat and still getting cold air from the vents. HELP! Cold in Alabama

Heater core probably clogged, and needs flushed out. Is the coolant brown and rusty?

If the RADIATOR and RESEVOIR BOTTLE are both full of coolant, then the heater core is probably plugged as stated above. Check the radiator by removing the cap only when the engine is cool. This is a good advertisment for proper cooling system maintenance. You may be able to dislodge the clog with a garden hose attached to one side of the heater core. Take both hoses off where they go thru the firewall into the heater. With the right size of garden hose, you may not even need a hose clamp. Run the water at full force.

If the above doesn’t fix it, try a 50-50 mix of CLR (Calcium Lime Rust) available at any Walmart. It is acidic, and will clean out darned near anything. WEAR RUBBER GLOVES. I use a big funnel with about 18" of old heater hose attached to it, and catch the outflow with another hose pointing upward so that the fluid seeks it’s own level and can be allowed to sit inside the heater core for a minute or so. Then I move THAT second hose downward and catch the effluent for proper disposal. A huge drain pan is helpful. Don’t leave the solution for long, as it can eat right thru the core’s aluminum. THAT’S an expensive repair. Then flush it again with clean water. I’m not going to say it works every time, but I’ve had about a 90% success rate on Tauri. They seem to have this problem more than most others, although I did it on a Lumina last week.

OR… it may be a stuck blend door or a loose vacuum hose. Before trying to clean out the system, I would suggest making sure it is not something a little more simple. Usually clogging happens slowly and you loose heat, OK in Alabama you might not have noticed it, but I would check the blend doors first. I don’t know if they are controlled by wire or vacuum in your car. If vacuum you should be able to hear a soft “whoosh” sound when you turn the heat on or off.

Fords of this age commonly have the blend door problem. This door bypasses air around the heater and is operated by an electric actuator. Where the shaft of the actuator mates with the plastic door it cracks. If you can get the actuator out, a pin can be put in the shaft that sometimes makes it work. My 97 had that problem and think it lasted through 99 production. A proper fix should cost over $700. I cut a hole in the heater box and moved the door by hand to summer and winter position. It can be accessed by dropping glove compartment down.

Here is some good info on accessing the blend door actuator and the heater core on Ford Taurus.

The 92 Taurus I owned for about 14 years would not warm beyond a slight raise from cold. The heater was barely adequate as a result. It did this when it was new and after a thermostat replacement. I am convinced the by-pass hole around the thermostat was too large (that’s the only explanation I could come up with). If this is a design flaw that affected some of the engines (certain molds) you may have something like I had.