Help me out with a truck heater problem

[FloydV]

If you don't know the answer, can you point me to a forum. I've done a lot of net searching, but haven't found anything close.

I have a 95 Ranger. The radiator flows freely and the temp gauge goes to the middle fairly quickly. The heater blows cold air.

I disconnected the AC wire from the compressor which continuously cycles on and off unless I turn the blower to off. The heater air stayed the same temp.

I put my hands on the heater hoses and both get pretty hot. There is a bizarre valve on the attached pic. Looking at this, I can't tell which is in and which is out to try and back flush. I was thinking about detaching both hoses and trying to blow compressed air through the heater core. Manually pushing the valve open and shut doesn't do anything to help, though it doesn't move heat on or off.

I suspect that something is not opening the heater door, but I can't tell because I can't see crap looking under the dash.

 

[Mr Bogus]

that is the heater control valve.. turns water off/on to the heater core


If you turn the temp controller inside, the little arm you can see should move..

if it moves, water will be forced through the heater core if the valve is ok inside.. You can technically remove that valve and connect the hoses directly to the heater core..

DO NOT BLOW COMPRESSED air through the core... you could burst it... and besides, you could flow plenty of air through a plugged heater core

When you switch the defroster control (floor to windshield) can you hear doors working? the most common issue is a bad vacuum connection or a one of the vacuum check valves (you hear the defroster doors opening and closing when hitting the gas for any amount of time)

Verify vacuum at heater control valve (you can manually move it?)
verify doors (blend doors) are working in car
bypass heater valve and test (careful, hot water)

if everything above is working, you could just have a plugged heater core (replace with NEW only)

 

[FloydV]

I can feel no vacuum from the line when I take it off. I manually pushed the valve wire up and put a wire tie to hold it, but the heater still blows cold air.

The only thing I can think of is to pull the heater exit hose loose and see if water flows out. If you look at the valve you can't tell if the hose on top stays the hose on top on the other side or whether the valve is actually reversing them. Looks like this


-----X
-----X------ in
X------ out

 

[Mr Bogus]

can you hear the doors in the dash working when you move the duct controls? does the defroster happen to be running?

(you wont feel any vacuum at the valve... not enough to feel, (a vacuum gauge is needed)


IF the defroster in the car is stuck on, you have a vacuum source issue..

 

[Mr Bogus]

you can remove that valve and hook the hoses direct to the heater core.. (may need to use a couple heater hose splicers (like the kind in flush kits) provided the air control doors are working in the truck..

if bypassing the thing does not work and you can not feel any heat:

heater core is plugged
Thermostat could be stuck open on motor. (you should be able to feel hoses too hot to touch)

or the temp blend door is buggered

 

[mike04busa]

Sometimes the temp doors break in the ford's.Make sure the blend door moves,flush the heater core both ways to see if anything come's out.Good luck.

 

[Projekt]

Biscuit beat me too it but I'll say it again.. Do not blow compressed air through the heater core.

 

[Spudley]

Look underneath dash....locate blend door actuator...validate vacuum from control is moving vacuum servo at blend door actuator. If good and it wanders with the heat adjustment knob, or slider on dash then you might have a plugged heater core. Also, remove heater vacuum valve and check with vacuum pump or your mouth will do. Take small diameter rubber hose and connect to heater control valve vacuum nipple. Watch for action of valve while building suction on valve. Those valves are designed to recirculate hot liquid when engine is running and no heat is selected. The two engine mounted hoses should be warm. The two hoses on the firewall side shouldn't be hot until vacuum is applied and liquid is circulating. My guess, your vacuum heater valve is stuck. Replace with new, about $15, and report. The vacuum hose that is connected should only have vacuum when heat is selected on the dash.

Have you run any stop-leak through the system as of lately ?. Especially that Block Seal stuff from Bar's. It says to run engine with heater on for at least a half an hour so as not to lock the valve closed, and / or plug up heater core.

Peace.

 

[FloydV]

Thanks guys!

I'm going to disconnect the heater hoses and use the T that fits to flush the heater core only, in both directions. The hoses are slightly hot, but not real hot.

If water flows easily through the heater, then I'll have to assume it is a door not opening (although it does cycle through defroster, straight out, and floor.
I did notice that I lost in increase in AC flow or noise when I put it on Max Air. It sounds just like Regular AC.

I have not seen the valve on the hoses move. I have moved it in all the way and tied it in place with no change. I will remove it just to check that it might be a cause.

If all that fails, I will have to assume it is the door, or worse, the dash controls. I want to replace the car and get rid of the pickup in April. I will start getting my first (62 years old) SS checks. The way it works, the wife gets the new car, and I will get her 01 Camry. She actually wrote the check with a smile to pay for the Busa, so I can't gripe. And no, I'm not giving up the Busa until I go blind or die!

It gets to -30 here in the winter, with lots of snow. I keep it in the garage, but you can see how the windshield will become too fogged or iced to see with no way to defrost it once I take it out of the garage.

 

[Mr Bogus]

most of the vacuum control issues are "normally" a broken vacuum line under the hood..

Ford uses black poly line (very similar to an unnamed nitrous bar here) that becomes very brittle with time and heat cycles.. it cracks, breaks or just falls apart and you loose the vacuum to the control head.. This is the FIRST thing I always check on these units..

by switching the the system from heat to defrost (you can hear the air changing directions and the doors operating) you verify that you have good source vacuum..

A plugged heater core is pretty common too.. they can flow fairly well and still not have adequate heat exchange.. (hot line in, cold out is a pretty good indicator)

 

[Projekt]

Re: Thanks guys!

And no, I'm not giving up the Busa until I go blind or die!

 

[Casperle]

The blend door is ran by electric motor with plastic gears that strip off in alot of fords. It is white or black right behind the glovebox door Hold the sides of the door in and the door will fall conpletly open dumping everthing on the floor. It will be at the top left of the opening with the plug facing you. Key on, run the blend knob all the way cold to hot with the defroster vent or heat on. Have a good small flash light look between the motor and the heater box you will see the shaft same color as the motor goin down into the box to the blend door is it turning back and forth? If it is its the blend door is broken at the top I just replaced one today in a 98 Ranger very common in Ranger,Explorers,and Windstars. Trust me.

 

[Mr Bogus]

The blend door is ran by electric motor with plastic gears that strip off in alot of fords. It is white or black right behind the glovebox door Hold the sides of the door in and the door will fall conpletly open dumping everthing on the floor. It will be at the top left of the opening with the plug facing you. Key on, run the blend knob all the way cold to hot with the defroster vent or heat on. Have a good small flash light look between the motor and the heater box you will see the shaft same color as the motor goin down into the box to the blend door is it turning back and forth? If it is its the blend door is broken at the top I just replaced one today in a 98 Ranger very common in Ranger,Explorers,and Windstars. Trust me.

good deal, I did not know they were electric on these... been a few years since i had to drop any heater cores.. Now about the evaporator on the Lincolns...