99 Limited has. no Heat

[bigred4x4]

IIRC, on the OHV, the heater valve vacuum line originates at a black plastic vacuum reservoir sphere under the coolant recovery tank and above the wheel well. Mine is a hard line, grey in color. The SOHC might be the same/similar.

Could be wrong but that vacuum reservoir might be only for 95/96 ex with CAD.
I'll check on mine when I get home and post a pic of where that vacuum line goes if you didn't figure out by then.

Also I'd if the heater core feels warm and there is not even the slightest change in temp when you turn the cold hot knob then blend door sounds likely if it was working then you should feel some difference.

And becoming elite explorer,a big reason why I did it is because they (explorer forum) hosts your image or video or whatever and it's super simple with a phone plus you get a lot lot of other benefits worth every penny of the $20 a year. Otherwise you'd have to have a third party imaging account and put in url to pic to post them here

 

[koda2000]

Could be wrong but that vacuum reservoir might be only for 95/96 ex with CAD.
I'll check on mine when I get home and post a pic of where that vacuum line goes if you didn't figure out by then.

Also I'd if the heater core feels warm and there is not even the slightest change in temp when you turn the cold hot knob then blend door sounds likely if it was working then you should feel some difference.

If both the hot water and return lines from the heater core are hot, then the heater control valve is working and the water is flowing through the heater core. The OP said he has the EATC HVAC controls (no temp knob). If hot water is getting into/through the heater core and you still don't get any heat, then the blend door is either broken or not opening. To determine which, the actuator located on the heater plenum, behind the glove box, needs to be removed and tested. It's a PITA to do this, as the rear screw is near impossible to remove (unless you have tiny hands), but if the problem is with the actuator or blend door, that's how you can determine which.

As far as posting pics, you can pony up the $20 a year to become an Elite member, or use imgru (PhotoBucket has recently made changes and only works if you have the necessary extensions for your browser).

 

[BrooklynBay]

Hard plastic vacuum lines get brittle as they age then start to crack. Since you only have A/C diverting to the floor, this tells me that you have some vacuum on the lines. The default operation for no vacuum on the lines is the defrost setting for the windshield.

 

[mfitz725]

I just went out and double checked this thing. I made sure that valve was all the way open and let the engine warm up good. I am getting some heat, not as much as I would expect. Checked the hoses again and while the input hose is hot, the return hose is barely warm. Is it supposed to be as hot as (or close to) the input side? There is not enough heat in the vehicle to make me think that much heat transfer went on and maybe the core is somewhat blocked. I will try and flush it tomorrow but will only have the garden hose to force water in. Should that be enough pressure to maybe get it flushed out? I've got nothing fancy here to really work with that is assuming that return line SHOULD be warmer than it is.

 

[mfitz725]

Hard plastic vacuum lines get brittle as they age then start to crack. Since you only have A/C diverting to the floor, this tells me that you have some vacuum on the lines. The default operation for no vacuum on the lines is the defrost setting for the windshield.

Yes there no question about that part of the vacuum system. My problem is I don't have a vacuum line to hook up to the correct heater valve since some idiot put a piece of plumbing in place of where mine should be.

 

[BrooklynBay]

Do you have an infrared gun or a thermometer to check the temperature of the cooling system once it reaches the normal operating temperature? It should be a maximum of 195* F when it warms up, but this amount constantly varies. You should see the temperature gauge move back & forth as you drive. Check all of the vacuum lines for rubber caps or screws which were used to plug the lines.

 

[mfitz725]

Do you have an infrared gun or a thermometer to check the temperature of the cooling system once it reaches the normal operating temperature? It should be a maximum of 195* F when it warms up, but this amount constantly varies. You should see the temperature gauge move back & forth as you drive.

Unfortunately no to both items. As I recall the guage usually hovers around midpoint.

 

[mfitz725]

Here, finally, is a pic of what is installed as a heater control valve on my Limited. I gave in and joined up the Elite Explorers to make all this easier. As you can see this is clearly not an automotive part and also see my conundrum over no vacuum line when I replace it for the real thing.that's why I need to know where the line originates from. Is it on just general vacuum system or does it only have vacuum to be on or off and controlled by the heating system.

 

[BrooklynBay]

That's a very odd looking valve. I expected to see something similar to a ball, gate or a globe valve.

 

[koda2000]

The input and output hoses to the heater core should feel like about the same temp. Especially if your not getting heat in the cabin. If your going to flush the heater core with a garden hose, push the water from the out side of the core and let the water come out the in side. Doing it in this direction may help to push out any blockage and scale.

 

[bigred4x4]

This is my vacuum diagram I tried tracing the line off of the valve and it seems to go through the fire wall it is grey and the only lines connecting to my vacuum reservoir bulb near by were black. It's dark and wet outside. My guess is maybe they removed the line maybe? And replaced it with a manual control valve i I'm still leaning on blend door or blockage in heater core shouldn't be too hard to pin point.

 

[lobo411]

Looks like some genius broke the hard plastic vacuum line. Rather than running down to Pep Boys and buying $1.99 worth of replacement line, they did this. Brilliant!

 

[koda2000]

The vacuum line and vacuum controlled heater valve are not that important. In later years Ford did away with the heater control valve completely, so you should be able to just leave your manual valve open all the time and allow the blend door to control whether or not you get heat. Just make sure your broken vacuum line is capped off. It currently seems like your main issue is a clogged heater core. Don't worry about the vac line or control valve and try flushing the core.

On old vehicles it's common to encounter all kinds of strange, unorthodox repairs. I had a list as long as my arm on my '01 ST. Just repair the stuff as necessary.

 

[Turdle]

Back up a minute. let's check the coolant level in the radiator. Not the reservoir, the radiator itself. take off the cap and make sure the radiator is full. Loss of heat is usually attributed to low coolant level in the radiator.

If the rad is full, IMO the heater core is clogged. You should have the same heat on both hoses, unless there isn't enough coolant getting there.

You also need to be looking for a hard , grey plastic vacuum line.

 

[mfitz725]

The radiator is full, I already checked there. I wasn't able to get to flushing it today, will try for Thursday. We'll it's Thursday already you know what I mean. I'm having the additional trauma of the hood support struts not holding. I've ordered new but will be a few days. I will look for the missing vacuum line as well. Like I said I'm getting a little heat now, just not enough. I'm pretty sure the blend door is working correctly as I switched back and forth between A/C and heat several times and definitely feel the difference. Will keep you updated.

 

[koda2000]

The radiator is full, I already checked there. I wasn't able to get to flushing it today, will try for Thursday. We'll it's Thursday already you know what I mean. I'm having the additional trauma of the hood support struts not holding. I've ordered new but will be a few days. I will look for the missing vacuum line as well. Like I said I'm getting a little heat now, just not enough. I'm pretty sure the blend door is working correctly as I switched back and forth between A/C and heat several times and definitely feel the difference. Will keep you updated.

In the mean time, a piece of PCV pipe makes a really good, inexpensive hood prop rod.

 

[BrooklynBay]

You could use a Vise Grip too. Lisle makes a few nice hood prop tools. I have the smaller one with the thumb screw.

 

[mfitz725]

You could use a Vise Grip too. Lisle makes a few nice hood prop tools. I have the smaller one with the thumb screw.

I'm not sure I understand that. I'm talking about the hydraulic struts that keep the hood open. I don't see where vise grips would help there.

Was unable to flush the core again as my roommate is having a new roof put on the house and I can't get to the hose right now. Will try to get it soon.

 

[david4451]

The grey vacuum line on my ST goes from valve on heater line(front right on engine) and under blower motor. It actually goes through the plastic face of blower motor at bottom of it and connects to vacuum line inside passenger side foot well.
It looks to me(if yours is the same) as if this vacuum line controls the valve that allows or blocks off hot water getting to the heater core. Hope this helps.

 

[BrooklynBay]

The hydraulic strut consists of 2 parts. The inner part which is thin goes into the outer part which thick. Grab the thin part with a Vise Grip. This will prevent the 2 parts from collapsing into one another.