99 Limited has. no Heat

[mfitz725]

I have a 99 Limited 4.0LSOHC with the EATC system. I discovered today that I have no heat. A/C works great and can switch over to defrost, panel or floor vents with no problem. I am not sure where to start looking for the problem as I have understood the blend door is a problem if you are getting hot air all the time.

I am wondering about the heater control valve. Mine for some reason has an actual valve (with threads) on top of it. Is there a way to test this? Or am I barking up the wrong tree. Any suggestions on what to check would be helpful and appreciated.

 

[bigred4x4]

I don't know about yours but mine has a vacuum operated diverter valve (located passenger side near low pressure port for a with two hose s going to it to direct coolant into your heater core maybe pull this out and see if it's working. And test vacuum going to it

Are you talking about the same thing? Can you post a pic?

 

[mfitz725]

I am trying (with little success) to post a pic. It look like someone has installed a shutoff valve in one of the lines. I ran out to take the pic in the rain (in Atlanta here) couldn't get the valve to turn. Will try again to post a pic when I can use a pc and not my phone.

 

[BrooklynBay]

Did you feel the heater hoses to see if they are hot? I had this issue a while back, and it turned out that my heater core was clogged. I used a tool called the kinetic water ram which I use to unclog drains on it, and it cleared the blockage right away. I connected it to one of the heater hoses. The bits of junk blew out from the other hose.

 

[bigred4x4]

Hopefully not because the heater core is toast and that was a bandaid as replacing it isn't fun.

 

[bigred4x4]

Did you feel the heater hoses to see if they are hot? I had this issue a while back, and it turned out that my heater core was clogged. I used a tool called the kinetic water ram which I use to unclog drains on it, and it cleared the blockage right away. I connected it to one of the heater hoses. The bits of junk blew out from the other hose.

Good idea you could probably also use an air compressor to blow it out but if somebody put a manual shut off on it that tells me that it was probably leaking.

 

[mfitz725]

Did you feel the heater hoses to see if they are hot? I had this issue a while back, and it turned out that my heater core was clogged. I used a tool called the kinetic water ram which I use to unclog drains on it, and it cleared the blockage right away. I connected it to one of the heater hoses. The bits of junk blew out from the other hose.

There isn't much I can do tonight will have to wait for Irma to clear some tomorrow. Where did you get this kinetic hose, don't believe I've ever heard of one of those.

 

[bigred4x4]

It's a plumbing tool to unclog drains try your local plumbing parts supplier but there not cheap (he probably has one for work reasons) I'd try the air compressor if that is in fact the case unless you don't have one of those you could try blowing in the hose and see if coolant comes out the other hose that comes out of the firewall you should be good but like I said I'm willing to bet it's leaking I see no other reason for the cut off valve added inline.

 

[BrooklynBay]

You could test the heater core by connecting a garden hose to it. The water pressure might even unclog it. I wonder why they would install a shut off valve instead of bypassing it if it's leaking. Maybe the automatic control valve is bad, so they used a manual valve to control it. Open the valve in the heat setting, and see what happens.

 

[BrooklynBay]

This link has information, photos, and videos about the kinetic water ram tool: http://www.drainbrain.com/pro/waterram.html

 

[mfitz725]

You could test the heater core by connecting a garden hose to it. The water pressure might even unclog it. I wonder why they would install a shut off valve instead of bypassing it if it's leaking. Maybe the automatic control valve is bad, so they used a manual valve to control it. Open the valve in the heat setting, and see what happens.

That is what I'm going to do tomorrow. If I find out it's a leaking core I don't know what I'm gonna do. I'm not sure I should have bought the damn thing. It seemed fine when I got it but who'd a thunk to look for that. In the summer I was more concerned about the AC working not checking for heat. I'll let yall know how it goes.

 

[mfitz725]

Well here's what we have now. I turned the valve with the engine running and don't seem to have any core leaks. After letting it warm up I still don't have any real warm air blowing the controls are set for 90 degrees (it's set for floor only so the A/C won't come on). So I'm left with 2 problems.

1. If I put in the correct valve where do I hook up the vacuum line. There is none there to be connected and I have no idea where it was supposed to originate from.

2. Why no heat out the floor vents. I dropped the glove box and tried to feel around to the heater core and it SEEMED warm. Could the blend control be stuck in the cool position? I guess I can try and take the control out and see if it's actually working but it's not clicking or anything.

Input on these two items would be appreciated.

 

[BrooklynBay]

Did you check both heater core hoses after you opened the valve with the heater on to see if they were hot? What does the temperature gauge show? Maybe the previous owner removed the thermostat or installed a low temperature thermostat. Check the heater hose lines for pinched or kinked hoses.

 

[mfitz725]

Did you check both heater core hoses after you opened the valve with the heater on to see if they were hot? What does the temperature gauge show? Maybe the previous owner removed the thermostat or installed a low temperature thermostat. Check the heater hose lines for pinched or kinked hoses.

The hoses were hot and had no kinks. The stupid valve is 18 bucks at Autozone I can't imagine trying to cheap your way out of that. And like I said now the problem of no vacuum line to hook to it.

 

[bigred4x4]

Could be vacuum related isn't all the components vacuum driven ie blend door... Could be wrong there should be a vacuum diagram on the sticker in engine bay I'd check all vacuum lines hey at least your core isn't leaking that was worst case senario now it should be something a little more simple might just take a minute to find it

 

[lobo411]

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.

 

[poker4me007]

is this the heater valve, the vacume line runs under the heater blower motor housing on mine, maby you'll find it broken there...

 

[mfitz725]

Could be vacuum related isn't all the components vacuum driven ie blend door... Could be wrong there should be a vacuum diagram on the sticker in engine bay I'd check all vacuum lines hey at least your core isn't leaking that was worst case senario now it should be something a little more simple might just take a minute to find it

Don't recall the diagram but will look for it. I thought the blend door was electrical only. I know the vents are all vacuum driven though.

 

[mfitz725]

is this the heater valve, the vacume line runs under the heater blower motor housing on mine, maby you'll find it broken there...

No, that's what is supposed to be there. There is literally a hand valve sitting there in its place with no vacuum connection. I've never figured out how to post pics on this forum, especially from my phone since I use it mostly. You just wouldn't believe what's there.[/QUOTE]

 

[koda2000]

It could be the blend door actuator (electrical) is not working. We have this problem in my daughters '00 Mountaineer with EATC HVAC controls (the EATC and manual control models take a different actuator). When ours broke we got heat only. I removed the actuator, took it apart and removed the crescent shaped drive gear, drilled a small hole in it and attached a piece of bailing wire, which I pull or push to get heat or A/C depending on the season. I could replace the actuator, but it hasn't been a priority to-date. The actuators tend to break in one of two ways, either stripped gears, or the small electric motor stops working. The EATC controller unit can also no longer sent the signal to the actuator, due to cracked solder joint on the circuit board.