Hi all,
So 2 years ago, all of a sudden, DaveO's engine temp gage began reading cool and the heat stopped working much at all. Barely enough to take the bite out of the air. It's a 93 Ford Ranger with a 4 cyl, 3.0 L with 370 K miles on it (It is all original cept for the clutch, runs fine and it still doesn't burn oil)
Two years ago, we replaced both temp sensors, flushed the radiator and the heater core with water and compressed air, replaced the water pump and the thermostat, checked the operation of the thermostat in a pot of water, checked that all hoses were unrestricted and that flow through the heater core was unrestricted. the heat didn't work unless the radiator hose was clamped shut. It would work a little better with cardboard in front of the radiator. Of course it used to work just fine and suddenly stopped working, so it should work just fine without any need for weird modifications.

Last weekend, we needed to change the timing belt, so while we were in there, we re-replaced the water pump and thermostat with motorcraft brand stuff, we checked the operation of the thermostat in a pot of water, replaced the radiator and burped the system very very carefully and thoroughly using a funnel mounted to the top of the radiator (with the front end jacked up and the engine repeatedly revved and heated and cooled and reheated to get out all the air. Air came out for a long long time.


The heat still barely works. The engine temp gage is reading cool, too. The hoses to and from the heater core get hottish at times, but don't stay hot. I hear I need to lift the front end way up and rev it until it sounds like its gonna come apart in order to get all the air out. I haven't done that yet. I'm also considering cutting the lines to the heater core and installing radiator flushing hardware in them to allow air to escape from there, too.

Honestly, though, I am completely baffled. Does anyone know what I need to do to get the heat to work?
ray

 

thermostat could be bad?

 

does your engine use a air control valve to the heater core
if it does ,, then you have a vacuum leak some where along the vacuum line to control valve
newer rangers use a 2 way valve
( only channels hot coolant to the heater core when you turn on the heater )
or just directs the hot coolant back to the radiator

 

Hey cheese man,
Can the air control valve be seen in the engine compartment, or is it only visible from in the pasenger compartment?
The reason I ask is that there is no such device in the engine compartment. the 2 coolant lines that go from the engine to the heater core there at the firewall have nothing inline other than a fluid temp sensor.

 

Your ( blend door ) is bad!!

 

i will look after work when it is sunny out ( and warm )

 

click this >>>>> Heater Blend Door Repair On The 1993-1997 Ford Ranger