Heater Bypass 91 Explorer

[MikeP]

On my 1991 Ford Explorer (about 248,000 miles, bought it in July 1990) The leaking of hot air from the heater into the incoming air raised the temperature of the outside air and reduces the temperature of air when the air conditioning is turned on. I complained to Ford about this about a week after I bought it and it was not until a long time later I learned about this crummy blend air design which never worked on my Ford. I cut the two hoses to the heater and installed a bypass. I used two 5/8" barbed elbows and 4 hose clamps and a short section of heater hose. When the weather turns colder in October I will use two 5/8" barbed straight sections and 4 hose clamps to reconnect the heater to the coolant flow. It seems that the coolant temperature gage reads somewhat cooler with that heater bypass installed.

 

[Maniak]

Go to your local auto parts store and tell them you want a "heater control valve" from a 1994 explorer. That valve does what you did, but is vacuum controlled. I have it hooked up so when I'm on max a/c it not only closes the door (recirc door) but it also makes the water bypass the heater core. I tapped into the vacuum line under/behind the glove box as the line down there is used to close the recirc door and only get vacuum when your in max a/c.

~Mark

 

[MikeP]

Thanks Maniak.
Can this 1994 Ford Explorer heater control valve be switched manually or does it require the vacuum connections?
I see that there is a Camco "Quick Turn Permanent BypassKit for water heaters on a Ford Explorer.
Permanent installation of water heater bypass kit
Brass valves provide non-restrictive flow
Kit includes one quick turn bypass valve, one backflow preventer and crimp resistant nylon reinforced hose.
JC Whitney shows this on their website.

I did the "quick & dirty" bypass because it got a little warm here in Washington State. Having the heater bypass definitely helps the air conditioner provide cooler air.

Mike in Seattle

 

[Maniak]

It uses a vacuum connection.. I suggest it be hooked up to the vaccuum line that is connected to the blend door (behind/bottom of the glove box).. That way when your on max a/c it will bypass the heater core.

~Mark

 

[marragtop]

Go with the vacuum hookup. Also, don't confuse your problem with the 'blend door' problem experienced in the Gen IIs. The Gen I is pretty straightforward.

 

[ernzo]

How about without AC?

I was about to do this mod on my 91 (regular 'vent' air is quite warm almost hot).

If I want to modulate the charge in the heater core while still using just 'vent air', I will have to bypass and reattach when it cools off, correct?

I will inspect the blend door as well (i have a gen I 1991, but I suspect that something is not blending corectly...) , but my experience is that that type of system is less than perfect at best.

Anyone actually use the camco solution sold at JC Whitney? I could not really figure out how it worked from the pictures.

 

[Maniak]

I was about to do this mod on my 91 (regular 'vent' air is quite warm almost hot).

If I want to modulate the charge in the heater core while still using just 'vent air', I will have to bypass and reattach when it cools off, correct?

I will inspect the blend door as well (i have a gen I 1991, but I suspect that something is not blending corectly...) , but my experience is that that type of system is less than perfect at best.

Anyone actually use the camco solution sold at JC Whitney? I could not really figure out how it worked from the pictures.

The camco stuff is really just T's with manual valves. I've seen some old school heater bypass kits on older fords. Bascially its a single "valve" that will bypass the heater when you close the valve using what looks like an old school choke cable.

~Mark

 

[Maniak]

If you don't want to use the max a/c vacuum source, the following should work.

P/N 4100173 -cable driven

P/N 4100663 - electric


I found those here..
http://www.acmeair.com/partsguide.htm

~Mark