I've searched and search so I'm hoping you guys can help me. I have an 02 ranger 4x4 with a 4.0 and even on the heat setting it's only putting out cold air. It's rather difficult to drive in 0 degree weather. I've checked and had a mechanic check the blend door and it's working correctly. I've also flushed the heater core and still nothing. Any help will be appreciated more than you can imagine. Thanks guys!

 

I have a 3 liter so it is different, but when the engine is fully up to temp and the heater control is turned to its hottest setting, feel the lines going into the heater core, they should both be hot.
If one is cold, then the valve that controls the flow of coolant to the core is not opening.

I think the 4 litres may have it in the engine bay.
Some are controlled by vacuum or cable.

 

Thanks for the reply! The outgoing hose from the heater core is definitely colder than it should be. I'll try my best to trace it down in the morning

 

According to Rock Auto, this is what your heater valve looks like.
It's vacuum actuated, so if it is faulty, you can disconnect the vacuum unit and physically open the valve so you at least have some heat.

I think it's located in the engine bay, but not entirely sure.

With engine running have a friend turn the heater control back and forth from hot to cold.
You should see the valve move.

 

Here's a video, jump to 5:42.

 

My heater control valve is definitely not sitting on top like his, but I'll try to run it down. Thanks again

 

My heater control valve is under everything, next to the water pump, but I tied it to the open position and still no hot air. I may try to flush the heater core again as the inlet is warm, but outlet is cold. The vacuum line was on the control valve and working as well.

 

My heater core had good flow when flushing but was still clogged up at the bottom.

Heat control valve may only CLOSE for AC MAX setting, it blocks flow thru the heater core for cooler cab temps.
Heat control in the cab is the Blend Door and just the Blend door.
When closed(COLD) all air by-passes heater core, as it opens some air is passed thru heater core, then at HOT setting all air is passed thru heater core.

But one hose being cold at firewall means you have a circulation issue not Blend Door issue
Both hoses should be HOT to the touch if core has good circulation, same temp as upper rad hose if engine has warmed up, especially if you have blower fan off or low setting.
There is a small chance the heat valve is CLOSED all the time, broken, try to move it manually and see what it "feels" like

You can reverse the hoses on heater core at firewall, that will back flush the core while driving, I do this every few years to try and keep core clear

 

Wonder if something else is blocked and or the internal workings of the valve isn't broken.
The fact that one of the lines from the heater core is cold, says coolant isn't flowing into it.

You've already flushed the core, so I would look for something else.

A garden hose is usually used to flush the core, but don't turn the tap on full.

Sometimes reversing the lines into the core will help.

Flushing in both directions is important too.

 

Thanks Ron, you beat me to it again. :)

 

Thanks again guys! I did a reverse and normal flush yesterday. The heater control valve feel great and moves like it should. I'm thinking I may not be getting sufficient flow to the heater core and I can pull the hoses and flush it again in a short amount of time. I just need some heat! I've been working on my truck out here when it's 7 degrees

 

My heater core had great flow with garden hose, and both of my heater hose got HOT, but core was still clogged, lol, no heat in the cab

Since one of your hoses is cold your flow thru the core should be low and you should see that when flushing
The warmer hose is the IN from water pump and colder is OUT to intake, blockage anyplace between will slow flow in the whole system, so follow each hose to the engine end

 

I agree, it's odd to me. The water flows freely, although it may not be circulating correctly. I'll try to flush it again as soon as I get warmed up.

 

I should be more clear. It flows freely with a hose or funneling water through the heater core by hand

 

Ok guys, I just went out and opened and closed the heater control valve 50 times and nothing changed even though it feel and seems like it's working correctly. On a last ditch effort I simply unplugged the vacuum line from the valve and now I have some heat, at least at the very moment! Happiest I've been in weeks. While it's definitely not as hot as it's been before, at least I have some warmth.

 

Some heat is good, lol.

Another test you can do is to get a double barbed fitting, heater hose size
Pull off both hoses at the firewall and connect them together.
Warm up engine, BOTH hoses should now get VERY HOT, straight pass thru
That will tell you if heater core is plugged or if valve is the whole issue

 

After driving a bit my heater seems to be getting nice and hot! Both hoses are now getting hot as well so I think everything is circulating correctly. Since all that's really been done is removing the vacuum line from the heater valve, would that mean I need a new heater control valve? Thanks again guys!

 

Ron must be busy, so I'll answer.
The heater core must have been partially blocked, so it appears that it cleared itself out.

Before going out and buying a new valve, test the vacuum at the line first where it connects onto the valve to make sure that the vacuum switch on the dash is working right.

Of the three climate controls on the dash, turn the far right **** to "off" when the truck is running.
There should now be vacuum at that line.
Vacuum moves the valve closed. (according to the video) (and no coolant flow)

Now turn the control to any other position, other then the "off" position.
This will stop the flow of vacuum to that line allowing the valve to open. (coolant will flow)

If this test for vacuum passes, then it would appear the valve is faulty.

Note that if you have air conditioning and you turn the **** to one of the AC settings, that probably also applies vacuum to the valve to stop coolant flow.

 

+1 ^^^^

That valve's vacuum is operated by the Climate control in the cab.
And should have no vacuum unless AC MAX is selected.
The Blend Door is what the Cold/Hot **** controls, not that valve.

You can just plug that vacuum line for now, leaving it open might effect Vent Control, i.e. Defrost, Panel, Floor which are vacuum operated