'97 Exp No Heat...NOT blend door

[ColdExp]

This is my first time here....great site. I've read everything I can about this problem. Here's what I'm dealing with:

'97 Ford Explorer Eddie Bauer. I've had it for 5 years...great truck, except for having to replace the transfer case at 110K and the engine at 127K thanks to the timing chain cam tensonier problem. Now has 147K. After reading the threads I realize that I've had the blend door problem for the whole 5 years I've had it. Great A/C when on Max A/C but will cook you any time of the year if you choose any other setting other Max A/C. I have the automatic climate control. I would just switch back and forth between A/C and heat when it got too hot. But last week, all of a sudden....NO HEAT AT ALL! Now one has touched the temp controls. (we all learned long ago it didn't matter what the temp setting was anyway)

Here's what I've checked so far: Radiator is full. Upper and Lower radiator hoses are hot. Supply hoses to and from heater core are hot. Temp gauge registers normal operating temperature just as it always has. Blower works fine.

I've done the "Blend Door Fix" by Jeff Frank and got no change. I was wondering though, if there was a problem with the heater core (cloged or valve shutting off flow from engine) and it's not getting any heat, how would I know if the blend door fix worked or not?

Since all the hoses are hot, the temp is normal, and I'm not overheating, I don't think the thermostat is the culprit. Is this right?

Is there some type of valve that shuts off the core? How could the blend door, allthough not functional, allow heat all this time and then suddenly stop? I'm stumped!

Know in advance, your help is greatly appreciated! Baby it's cold outside!

 

[performancenut]

"Is there some type of valve that shuts off the core? How could the blend door, allthough not functional, allow heat all this time and then suddenly stop? I'm stumped!"

I would suspect a malfunction of the heater control valve, which is the device that, upon failure, would not permit hot coolant flow to the heater core. You should be able to find considerable information on this site.

 

[edward]

blend door

just had the no heat problem fixed. the blend door fix did not do it for me as the actual blend door was broken. we found this out so the whole dash had to come off. you couldnt tell the door was actually broken as there are sponge like lining on the door that held it together. so upon occular inspection the door was were it was supposed to be. only after the dash and the blend door system was pulled out that the actual problem was seen.

cost non dealer was 850.00 part was 160.00 rest was labor.

i was initially hoping the blend door fix would do me , unfortunately it was so.

good luck on your fix. my mechanic tried everything else first, thermostat,
heater valve etc but this is what it boiled out to be.

1995 x limited with eatc. hope this helps.

 

[ColdExp]

From what I've read in this forum it seems like problems with the heater control valve usually results in leaking of coolant. I don't have that problem. Also, if the HCV was the problem would both of the hoses to and from the core be hot or would one be cold? Are there situations where the HCV fails but does not leak?

 

[Nitrous SSC]

On mine its bass akwards. I either have full heat or full cold but my blend door was FIXED by the dealership. It all worked well for about 2 months and if I go from 90* to 85* it goes from super heated air that sets my right foot on fire to ice cold (winter)

I searched and searched on here and someone has mentioned it could be the little sensor in the dash, so I've ordered a new one. We'll see how it goes when I get it installed.

 

[TPLYNCH]

The heater control valve works via vacuum. If the vacuum fails, the valve doesn't work. If you have hot hoses going into and out of the heater core, then it is not the valve, and most likely your blend door managed to drop into the cold position.

 

[musclemaker]

I have a 97 explorer xlt with a similar problem. Started about a year ago.....My problem is that I have no control over the temperature of the heat....it is full hot. Regardless of where the cool-warm-hot knob is positioned, if the heat is on, its full hot. The air conditioning only works in the max air position. The funtion knob (ac, defog, feet, vents, etc) seems to be doing other things then it is positioned for....when set to defog, nothing comes out of winshield vents, but when set to a different setting, it does. (not sure exactly which does what...been used to it being screwed up for so long, i stopped paying attention...but you should get the idea). The fact that i cant control the temp would lead me to beleive it was a blend door, however the loss or disfuntion of the function knob leads has me thinking it is some sort of electronics problem??? Could a defective heat control valve have this affect? Vacum problem? A brand new vibration problem which began immediately after repairing my lost idler pulley and serpentine belt, brought me to this site and now that i have found all you fantastic people, i figured i should get the other little problems fixed....since it is pretty much a great little truck. Will greatly appreciate any help and will let you know what works. Thanks all.

 

[bplein]

I just replaced my Heater Control Valve.

All: Be aware: If you have heat ALL THE TIME, that's probably a blend door issue. If you have intermittant, or no heat, or your vehicle takes a longish time to warm up, and you've checked your thermostat, you may have a Heater Control Valve issue.

In my case, my heat would sometimes never come on. When it did come on, it was late and not as hot as I would expect.

I bought a new HCV from Ford ($39 plus tax) and went to replace mine. I immediately noticed that the vacuum line to the HVC was partially loose. This could have led to a vacuum leak, leading to intermmittant heat.

Upon removal, inspection of the water flow showed that the HVC was clogged. Partial opening/closing due to the above vacuum issue could have exacerbated this. Now all of a sudden this was making sense... once the engine got really hot, enough fluid would get past the partially clogged valve.

After replacing this valve, I have the following to report:

• Reliable heat
• More heat
• Quicker heat
• one less leak (this unit was also leaking)
• smoother idle (vacuum leak solved)

I highly suggest that people here test their HVC if they have a high mileage Explorer.

 

[BrooklynBay]

Welcome to this forum! Check these links for more information: http://www.explorerforum.com/forums/showthread.php?p=1387654#post1387654, and http://www.explorerforum.com/forums/showthread.php?t=152965.