94 Explorer Heater Core Question?
Thread Starter
|
Senior User
Joined: Mar 2005
Posts: 111
Likes: 0
94 Explorer Heater Core Question?
Ok, I noticed a leak the other day. Antifreeze. traced It down and I found out It was coming from a plastic fitting that Is attached to the Inlet and Outlet heater core hoses at the firewall. It has a vacumm line connected to It to I guess open and close the flow of water through the heater core. Does anyone know what this Is and do I have to have It or can I just run the hoses straight Into the heater core? I have checked the repair book and It does not show It being on the truck at all.
So does anyone know what this plastic fitting Is and what It does and Is It needed?
So does anyone know what this plastic fitting Is and what It does and Is It needed?
Thread Starter
|
Senior User
Joined: Mar 2005
Posts: 111
Likes: 0
First Off, Do I need the Heater control valve? This Is the frist time I have ever seen anything between the heater core and the hoses that go to It. I have worked on a few cars In my time and I always thought that the heater core hoses go straight Into the heater core. Why do I need to control the flow of water going Into the heater core?
I had to take the heater control valve off because It split open and right now I just have the 2 heater core hoses going straight Into the heater core. Is that going to hurt anything?
Second, Hello Jharger. Well I got the leak down to a drip and I am keeping a eye on It.
I had to take the heater control valve off because It split open and right now I just have the 2 heater core hoses going straight Into the heater core. Is that going to hurt anything?
Second, Hello Jharger. Well I got the leak down to a drip and I am keeping a eye on It.
Posting Guru
Joined: May 2002
Posts: 1,574
Likes: 1
From: Phoenix
I've yet to have to mess with my heater core on my 1993. Haven't gone and studied the system. But witha a quick glance, I didn't see any heater control valves in the engine compartment. I though it must be inside the heater core box...I'll have to look again. Basically, without a valve, you can't turn the heater off. Sure you can turn the fan off but hot water is still flowing through the core. In the summer, trying to run AC, the 2 systems will battle each other and you wont have cold air.
Posting Guru
Joined: May 2002
Posts: 1,574
Likes: 1
From: Phoenix
Yeah and I looked again at my truck and there is definitley no heater control valve inline of the heater hoses in the engine compartment. So it has to exist but inside the heater/AC box under the dash. With what you have posted so far James, you must have already opend up you heater core box.
Trending Topics
Thread Starter
|
Senior User
Joined: Mar 2005
Posts: 111
Likes: 0
No this Is not In my heater/AC box under the dash. It Is right on the firewall were the heater core hoses go Into the firewall and Into the heater core.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Posting Guru
Joined: May 2002
Posts: 1,574
Likes: 1
From: Phoenix
Since I hadn't had to mess with my heater/AC system yet, not bad for 175K miles, I didn't know what to be looking for to answer you question. Now I checked it out and reviewed the manual. You should not have a vacuum actuated heater control valve on a 94 explorer.
The system is different than the old days and the air will not flow through the AC and heater core at the same time. Well it does but the AC core and heater core are not right next to each other like the old systems. These now use a blend door to route the airflow away from the heater core when you switch to cold and have the AC on. Your manual should show this clearly.
So to answer your question, I think whatever you took off was added by someone, not stock. Running without it should be fine...unless it was added due to a bad blend door...hmmm, interesting thought. You did cap of the vacuum line right?
The system is different than the old days and the air will not flow through the AC and heater core at the same time. Well it does but the AC core and heater core are not right next to each other like the old systems. These now use a blend door to route the airflow away from the heater core when you switch to cold and have the AC on. Your manual should show this clearly.
So to answer your question, I think whatever you took off was added by someone, not stock. Running without it should be fine...unless it was added due to a bad blend door...hmmm, interesting thought. You did cap of the vacuum line right?
Posting Guru
Joined: May 2002
Posts: 1,574
Likes: 1
From: Phoenix
Savage, come on now!
It actual comes from the intake manifold - probable the tree on the rear drivers side.
But if this was added, and there are extra ports on the tree to add to, then there must be some other switch somewhere to actual it. Is there something under the dash that looks non-stock?
So I'm thinking if the previous owner was running the AC and blowing cool air through the heater core beacuse the blend door wasn't working and closing off that air flow path, he used this add on control valve to stop flow into the heater core. If so, he had to be able to actuate the valve some how. You should run some tests between hot and cold with AC and see how it works. If it's hot all the time, fix the blend door. There used to be a post at the top of this thread talking about it...but maybe for a later year...concept should be similar.
It actual comes from the intake manifold - probable the tree on the rear drivers side.
But if this was added, and there are extra ports on the tree to add to, then there must be some other switch somewhere to actual it. Is there something under the dash that looks non-stock?
So I'm thinking if the previous owner was running the AC and blowing cool air through the heater core beacuse the blend door wasn't working and closing off that air flow path, he used this add on control valve to stop flow into the heater core. If so, he had to be able to actuate the valve some how. You should run some tests between hot and cold with AC and see how it works. If it's hot all the time, fix the blend door. There used to be a post at the top of this thread talking about it...but maybe for a later year...concept should be similar.
Freshman User
Joined: Sep 2003
Posts: 47
Likes: 0
From: South East Ohio Area
You need that valve if you want to be able to control your cabin heat, if you run the hoses straight into the firewall by passing that heater control valve, the heat will be on all the time.
I just replaced that valve today in my 94 Explorer, because I broke the oem one, when I did my engine swap, trying to remove the hoses. It's much better having it inline and working. The vacuum line should go in to the heater (hot/cold) lever on your dash.
I just replaced that valve today in my 94 Explorer, because I broke the oem one, when I did my engine swap, trying to remove the hoses. It's much better having it inline and working. The vacuum line should go in to the heater (hot/cold) lever on your dash.