SO here is what I have:

98 ford Ranger 2.5L.

I have not heat from the vents, doesn't get warm at all. If I idle the enginer in 30 Degree weather it gets to almost the C.

Upper Radiator hose is hot, I have verified the thermostat is new and it opens at 192 degrees as it should. Replaced the Water Pump, Fan spins freely.

I have attempted to burp the system, it isn't kicking out anymore air from the lines that I can tell. I used a large funnel and filled it with Anti-freeze, it filled the radiator, burped the system and the reservoir filled to overflowing. All with the engine hot. (To be specific the funnel was always full of fluid so no air could get sucked backwards)

The heater core hose on the left when looking from the front of the vehicle does not get hot, the one on the right gets warm.

I'm wondering what the issue is, any thoughts?

I theorize that the heater core is clogged up somehow and that is why that left line doesn't get hot. There is no fluid in the cab of the truck from the core.

I'm at a bit of a loss, here, any help is appreciated.

 

You have a plugged heater core. Disconnect both rubber lines where they attach at the firewall and force water back and forth through the core with a garden hose until it flows clean, then put the hoses back on and you should have lots of heat.

 

I will try this tomorrow night and let you know my results.

If this works you have helped me resolve what has been a very uncomfortable problem in the winter. I will keep you posted, Thanks for the quick reply!

 

Agree it sounds like your heater core is plugged and not flowing. When you do the flush, start by going backflush, from the cool hose to the warm hose.

 

You may get a good flow using a garden hose, but the core may still be plugged. After flushing, if both hoses do not get hot, it's still plugged. The flow may be enough to heat one hose, but the coolant will have all the heat extracted when you have limited(clogged core) flow and the return hose flow will be 'luke warm'. Time for a new core.
There are chemicals you can apply, but results are not uniform. Success not guaranteed.
Was the cooling system maintained or neglected? If there's a shutoff, it is possible the coolant 'sat' in the heater core for long periods when the A/C was in use, and finally plugged it up.
Good luck with flushing. Hope for the best.
tom

 

When you where attempting to burp air did you park on incline( engine higher than rear)and leave cap off and run till at operating temp till air is removed ? Could still have an air bubble trapped in core. Also agree on checking the flow control valve. Could disconnect it and bypass to see if you get flow after doing so to confirm before condemning heater core. FYI when working properly if like my 2.3 it will blast you out of cab with heat.

 

I was able to flush the core, it is blowing hot air when driving, but if I idle it begins to cool off. Unfortunately it has gotten back up into the 60's here so it's not easy to tell what things will look like until it drops in temp again.

I'm thinking at this point it has something to do with the vacuum lines. Thoughts on this new development?

And Thanks to those who suggested flushing the core that helped immensely, it brought me to the latest come and go heat, which is better than completely freezing.

Thoughts on the new development are appreciated.

 

SIT:I'm thinking at this point it has something to do with the vacuum lines. Thoughts on this new development?


Ummh. Why? Do both hoses get hot? If not, you still have a flow problem, indicated by the 'heat when driving, but not...'.
I would suspect 1)low coolant - solution is to 'burp' 2)partially plugged core - solution to flush more or replace or 3)failing water pump with eroded fins - solution replace.
You should get, as stated before, both hoses hot, not just warm, or you will not get heat. If increasing engine rpm, and thus water pump speed, thus flow rate gets you heat, either there's not enough coolant, the core is plugged still, or the pump is defective. For the 2th time.
Where does vacuum enter, unless you think a vacuum operated shutoff valve is blocking flow... but why would it start now? If serious, use some duct tape to keep the valve in one position or the other, and check. Then check in the opposite position, but I suspect it is one of the other possibilities.
tom

 

I just had the exact same problem. No heat and guage would barely move. I changed my thermostat and my heat started working great but the guage still didn't move. The guage problem was with the coolant temp switch on the thermostat housing. There's 2 next to each other one is a sensor one is a switch.

If your heater core is clogged that's a different problem. To clean out my core I unplug both lines, blow it out with compressed air (not full blast), fill with water, blow, water and degreaser or cooling system cleaner, let sit for a few, blow, water, blow, coolant.

 

So here is what I've done and it seems to have resolved it mostly. It still takes a while to heat up to a little below the middle of the gauge, but I now have heat which is what I really cared about.

I replaced the heater core, Blend Door and Blend Door actuator.

Blend door had been broken, I knew it was an issue, but i was manually changing it so it wasn't a big deal until the heat stopped entirely. So i figured while i was this far into the dash I would just get it all out of the way and do both the blend door and the actuator. Shouldn't have made a difference and I don't think it did. But I include it as i did replace both in my process.

Even though the input and exhaust lines for the heater core were coming out hot 192\186 degree respectively after flushing the heater core I said forget it i'm replacing the core. I believe this is what the issue was ultimately. I theorize the the original core had filled up 2/3 of the way with junk so that the cold air just didn't warm up enough to make a difference due to the fact that so little of it actually hit a portion of the core that got hot.

To back this up, when I removed the old core, it was heavier than it should have been and very little coolant came out of it during the removal process.

a note for others in the future, the dash is a real pain to pull out, it might be possible to just to pull it without removing 80% of the screws but that's not how i did it. Also the is a bolt\nut in the center of the firewall (engine compartment side) that must be removed in order to pull the heater core box out....easy to miss if you don't know about it.

SO that's it, I replaced the heater core and all got warm again....just in time for our second snow of the season to hit.

Thank You everyone for the help and ways to do this that would save more money, in the end I just bought a $30 heater core and spent 10 hours fighting with a few extra nut\bolts...save several hundred on labor doing it myself. This is my first time in these forums and I must say I'm still proud to be a Ford Man! Good people here.