Hey all and likely RonD (lol)!

My '94 ranger is still without heat. I have topped off the antifreeze. When in the engine bay the left most hose is getting warm but the right one is not. In the cab the gage never shows the truck is warm. The slider seems to make a change so I assume the actuator is moving. What are my next steps? Thank you for any additional help. It was about 18 degrees F yesterday so heat would be a luxury!

 

Sounds like the heater hoses or exchanger are blocked... or worse yet, the t'stat isn't opening.

 

Engine not warming up fully, close to 1/2 on temp gauge, is most likely thermostat stuck open, as said above, but not related to no heat at all in cab
Simple test
Start cold engine, feel upper rad hose and heater hose, both will be cold of course
Let engine idle for 3 min or so
Feel both hoses again, heater hose should be warming up, upper rad hose should still be cold, if its warming up like heater hose then thermostat is stuck open


If one heater hose at firewall is warming up but the other is staying cold then heater core is clogged up, little flow thru it, in a 1994 its not hard to change
There are 4 screws with bolt heads under the dash below heater core, they hold a removable cover plate, one is up higher behind glove box, fold it down all the way to see it
After cover is removed put a towel down on the floor below heater core
If you haven't removed heater hoses at the firewall in engine bay from the heater core do so now
In the cab slide the heater core back away from firewall to get the hose connections inside the cab and lower heater core down, coolant will spill out a bit, reason for towel
Outside the cab try to empty out the heater core, you will most likely find coolant will not all drain out because of clogged passages inside

You can try cleaning the core although they are not expensive to replace
Hot water mixed with CLR or Vinegar can loosen corrosion in core, let it sit with mixture for 20min then drain AND FLUSH with garden hose in BOTH direction, repeat as much as you like
But............
Coolant has chemicals that prevent metal from rusting or corroding inside the cooling system
With Green coolant(silicate) these chemicals only last 2 years, which is why you need to change this coolant every 2 years
When a heater core(or radiator) gets blocked passages then no coolant can circulate thru them, so no protection in those tubes/passages any more, and they start to corrode
Eventually they will start to leak coolant out, in the case of the heater core coolant is leaked into the cab.............


In future you should reverse heater hoses at the firewall every 2 years or so, to reverse the flow thru the heater core, on ANY vehicle, this will help keep the heater core cleaner


Yes, the TEMP slider operates the Blend door in 1994, these rarely had issues, 1995 and up Rangers used an electric motor(actuator) which did have issue of failing
You can see the cable end of Temp slider above glove box opening, just have a look and move the slider you will see it moving the blend doors arm and hear door moving to its limits

 

Thank you for the responses. I have plenty to look at now, and know what I'll be doing this weekend! I'll keep ya posted.

 

@RonD I received a new heater core and thermostat from RockAuto. I just installed them, but sadly, I don't see a change. :(

I'll try to attach pictures, but the hose going to the top of the radiator gets warm, and the hose on the right going into the cab (looking in the bay towards the firewall) gets warm. The left hose going to the heater core stays neutral.

The gage on my dash didnt seem to change with the new thermostat. I did find that the old one had a small disk-like rock lodged in the spring. Weird.

Anyway, thoughts? I appreciate the helpful advice .

 

No, can't think of anything else

Cold engine
Remove rad cap
Pull off both heater hoses at the firewall
Put finger over one hose and blow into the other, coolant should come up at rad cap opening
Then reverse it, blow into the other one
Should be fairly easy to blow into either, so not blocked

Lower hoses down until coolant comes out both and put them back on, that will clear the air out of each hose, then reinstall them
Top up radiator

 

Sounds good, I'll have to give that a try! Thanks and Happy New Year.

 

It looks like I've got it working as good as it will be. I did what you said in the last post and threw some cardboard in front of the radiator. I made sure it was good and topped off and it appears to be blowing warmer than just outside air. Thanks for the help.