Change heater core

have you remover the hoses to the heater core as you have not mentioned them

Some times gunk builds up in the heater core.. Do a reverse flush on the heater core alone. You don't have to remove it. Disconnect both of your heater hoses. Preferably at the engine. If you have room to work right where the hoses connect to the heater core this will be the place to do the work. Try using a water hose. Add a high pressure nozzle to your hose and put it in the hose that returns water back to your engine, is essence you will be doing a reverse flush. Good Luck !!!

If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core. Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.

The first thing I would check is the level of antifreeze in the radiator. If it is low, you need to find out why. Hose or water pump leaking, blown head gasket, etc.

If it is not low, possible air mix door malfunction or clogged heater core.

Humm, that sounds like not enough hot water. So, verify the system is getting hot enough, like 195 to 210 or so...Is there enough water, probably, but check it. A pressure test helps to locate any leaks...

If all good so far, then at normal temperature, feel the hoses going into and out of the heater core...Are there any valves in these hoses, those are suspect and need to be tested. If you conclude that a restriction of waterflow in the heater core, you can sometimes get life back into it by reverse flushing that area alone.

Kind of nice to have the lube place change coolant, but they do not hook up for reverse flush...

Heater core replacement is typically hard and fragile, but it may not be bad on your truck...more room to work.

Heater cores are nasty and its' a ugly all day job. You have to take all of your dash board out to get to the core under the dash globe box in the firewall. Depends where you live but you can bypass a heater core by connecting the heater hoses together. Its' a quick fix and you will not have any heat at all but it will stop leaking. You have to get a shop repair manual for your ford then read up on the job. If you can tackle the job yourself you will save hundreds in labor alone. Write me back and rate me please.

Sadly "there" explanation is probly correct, when you say you have some but not alot of heat on low and then almost non on high, that is due to a plugged heater core. A heater core acts as a miniature radiator inside your cab. When the fan passes the air by it it picks up the heat and blows that into the cab. While doing that it also cools down the heater core. The more are you pass by it the cooler the core gets. What you can try first before replacing it is a coolant flush. This will run a mild acid like sollution through your entire cooling system. Sometimes that alone is enough to let more hot antifreeze run into your heater core thus giving you more heat. Another option is to disconect both lines into your heater core from in the engine compartment and run a hose into one , leaving the other to drain out. Depending on how plugged it is sometimes you can "Flush" out the buildup this way as well. G'luck and keep warm!

I experienced the same head ache. First attempt was to replace the thrmostat and after taking it apart I realized that there was nothing wrong with it. I then removed the plastic cover/panel located under the dash board on the passenger's side. (only a few 4-5 smalls screws) Removal will enable you to see the on/off switch/gate moving/rotating as you turn the knob to hot or cold positions, on the control panel. If that switch/gate seems to work ok, then the trouble is within the heater core. Many mechanincs suggested that I replace the heater core. A very expensive proposition.
I checked the heater core supply/intake hose and found it hot to the touch, while the return hose was nearly cold. It was definitely a heater core blockage. I removed both ends (supply and return) hose connections/clamps. They are located near the fire wall in the engine compartment. A special tool is very helpful to remove those clamps easily and to replace them as well. It can be done the old fashion way but this tool was a life saver and reduced work time to just minutes. (Tool is $70.00 bucks at auto parts store,so I borrowed mine from a mechanic/friend)
I then hooked up a garden hose to the return end of the heater core and reversed the flow of coolant/water through the heater core. My truck is a Sierra 2000 and I refuse to see how a heater core could get clogged up with clear coolant alone. To my surprise a flat piece of rubber about the size of a quarter blew out of it and the flow of water became unobstructed. I reconected the ends of the hoses to the heater core, replaced the lost antifreeze & everything returned back to normal. No money spent for something most mechanics suggested I replace control valves/switches ($280.00) replace heater core ($500.00) etc etc. I am glad I was curageous enough to tackle this myself and save a few pennies. Good luck, and I hope this will work for you.

9 times out of 10 on this old of vehicle its the heater core. If your car temp gauge is working and the car is heating up fine and the blower works then it is most likely your heater core. Not sure how hard it is on that car. SOme times it just under the dash takes about 30 mins but some cars you have to pull the dash out. The part alone is cheap. I would try logging onto autozone.com put in your car find the part (heater core) then look at the how to change section of auto zone.

Goodluck.

AUTOZONE.COM has excellent info for your vehicle. They have an online repair guide.

This link may get you to the guide for your car, please try.