heater valve

[ddoyle]

I am usin a heater control valve on my manta that came out of a mid 80's honda accord. It is cable operated, opens and closes the same and even has a control cable clip on it( the valve will work fine without cable secured in the clip). It has the same 90 degree bends as the original. The hose fittings are slightly smaller than orig. Very cheap and works great!

DAN

[likengtj]

I wonder if it can be also used in a GT?

What year Accord was it for? (85?)

[ddoyle]

I searched thru parts books till I found a valve that looked and worked the same as the opel. Then I went to wrecking yard and found the valve, not sure of year. I was going to order a new one if it worked ok but the used one has worked great and no leaks.
I dont know what the GT valve looks like, the manta is 90 degrees and the cable pushes to open the valve.

DAN

[Washout]

Has anyone come up with more details on this valve or any other part number we can use to replace the original heater control valve?

[jlthunder]

OGTS does sell a valve which will work in a GT. I haven't tried it so I can't say how well it works.

[ddoyle]

Monday when I get back to the shop I will look up the info for the Honda valve and post the part number and applications.

DAN

[Paul]

Dan,

Did you ever find the part numbers for the heater valve you used?

Thanks
Paul

[ddoyle]

Paul, I have looked thru my current stock of parts books but have had no luck. I will keep looking. I am pretty sure that it was a mid eighties Honda.

DAN

[billiard13]

Looking through available Heater Control Valves at the local Advance Auto Parts I didn't find anything that resembled a GT valve that fit a mid 80's Accord but the 86 Civic valve looks very similar in design.

[jeff denton]

Go to a truck shop and get one for a Kenworth. It'll be just what you need.

[jvandyke]

since my old valve was seized I've been looking for replacements, so far I've searched here and have seen references to mid $80's Hondas, an '85 Civic, there's new at OTGS ($69-ouch). One member (DESTEC) has rigged a solenoid valve up to his blower rocker switch, turning on blower either speed will also open valve, seems like a good idea
http://www.opelgt.com/forums/group-9...-blower-2.html

I came across this one early in a search, probably many like it:
Servo Heater Valve

Benefit: no mechanical cable to keep in shape, no risk of seizure transferring force to control slider and breaking stuff
Downside: another electrical device to keep happy,

Questions: the original mechanical valve is somewhat adjustable, (can open the valve a little or all the way) I wonder if this has any discernable effect on temperature control (I don't think so)?
So using a valve that is either completely open or completely closed won't matter?
Hooked up to blower switch:
How often, if ever would a guy have the valve open; heater core heated but the fan motor off? I can see maybe if you want a tad of defrost or some "ambient" heat. Just wonder from you long time GT drivers. I don't plan on driving mine all winter but I'm certain to see frosty mornings quite often.

PS old valve has been cleaned up and funtions but is pretty stiff, how much resistance is normal?

[markandson]

I don't have a working GT...yet...but many vehicles use a water flow valve to regulate heat in the passenger compartment. I would think that the GT interior temp. would be greatly affected by coolant flow to the heater core, especially since it is such a small car.

[jvandyke]

Originally Posted by markandson I don't have a working GT...yet...but many vehicles use a water flow valve to regulate heat in the passenger compartment. I would think that the GT interior temp. would be greatly affected by coolant flow to the heater core, especially since it is such a small car.

Yeah? I'd think that if the valve were a little open, or totally open (and there isn't much difference looking down into the stock one) it wouldn't matter much. Won't the core fill up and get hot pretty much the same, maybe it won't flow through quite as fast but it would get just as hot as the coolant in the end. I just assumed most of the temperature control was actually accomplished by the other cable attached to the temp slider, the one that controls the air damper valve inside the heater box which seems to control how much air comes from heater-core-hot-part and how much air comes from.....? somewhere else?

Another way to state it is: how much temp control does the heater valve have?

[namba209]

Coolant flow through the heater box determines the amount of heat available to the interior or defroster ducts. Also the fan switch position. You gotta remember, there will be "cold" air coming in through the heater box, normal heat transference will take effect, cooling the liquid in the heater core. The more coolant flow the hotter the air exiting through it. That's how the temp inside the interior is regulated. The air flow direction, heater or defroster is regulated by the air flow flapper valves. They control the amount of air flow to either the heater ducts or defog ducts or a combo of both. Once the air flow is opened to the max setting for heat, all the air available goes through the heatter core, where it goes is a further function of tat valve. Limiting the travel of the air flow valve initially, does have an impact of the amount of heat coming into the interior, less air flow, less heat. A couple of notes on this, early Ford heaters had no coolant flow regulator, they limited the air flow thrugh the heater core. Also, if you ever experieince an over temp condition, set the heater for full heat, open up the air flow valve to full flow, turn the fan switch on high and your coolant temp will go down a fair amount, after all the heater core is just a small radiator connected to the system coolant.

[tekenaar]

Originally Posted by jvandyke Yeah? I'd think that if the valve were a little open, or totally open (and there isn't much difference looking down into the stock one) it wouldn't matter much. Won't the core fill up and get hot pretty much the same, maybe it won't flow through quite as fast but it would get just as hot as the coolant in the end. I just assumed most of the temperature control was actually accomplished by the other cable attached to the temp slider, the one that controls the air damper valve inside the heater box which seems to control how much air comes from heater-core-hot-part and how much air comes from.....? somewhere else? Another way to state it is: how much temp control does the heater valve have?

Quoted directly from the 1973 FSM: HEATER SYSTEM - GT section:

Air Inlet-Defroster Control (Upper Lever) - This control opens and closes the air inlet and heater-defroster air door which channels the air flow to either the heater outlets or defroster outlets, or to both outlets simultaneously, depending on the position of the control. Temperature Control (Lower Lever) - This lever regulates the flow of coolant through the heater core and the amount of air that can by-pass the heater core thereby increasing or decreasing the air temperature proportionate to its travel (toward ■ - warm; toward ■ - cold).

[jvandyke]

Yes, I know how it all works, mostly. I just wonder how much temp control will be lost if the heater valve is a solenoid switch which is either open or closed instead of having a partial setting. I'd think that even a partially open valve would allow the pressurized coolant to completely feed the core. Quite likely I'm wrong. I'm thinking of a garden hose, put your thumb over the end to block it to half it's original opening size and it just comes out faster, the volume of liquid getting through doesn't change much, right? So I'm thinking a partially open heater valve doesn't do much to effect the temperature in the end, the air flow valve does more, the pressurized coolant is much dissuaded by a partially opened valve.
Since DESTEC has done it, maybe he'll chime in.

[tomking]

thumb over the end to block it to half it's original opening size and it just comes out faster, the volume of liquid getting through doesn't change much, right? So I'm thinking a partially open heater valve doesn't do much to effect the

Wrong! The volume changes too. that is why you can modulate the temperature inside the vehicle by opening or closing further this valve.

[jvandyke]

Okay, but even if the volumn drops won't the core soon be as hot with say 5 gallons/minute running through of 200 dergree coolant as it will with 7 gallons per minute of 200 degree coolant. I'm just not convinced that a moderate change in volumn, once things are all heated up is going to change the temp coming through the vents in the car but I readily admit I don't know squat about this stuff. It does matter though because if I opt for an electric valve and I'm wrong and I can't control temp then I'll be grumpy.

[namba209]

Remembering when I changed the control panel from the original plastic to the aluminum one from OGTS and having the complete heater package out of the car, the heater control lever for the coolant had an additional cable on it. So I'm gonna presume Otto is correct in that the second cable also controlled the incoming air flow through the core as well as the water temp valve. So, that being said, it would appear you would need both the water temp valve working, either by cable, vacuum or electricly, and still use the second cable on that lever for air flow control. This is getting to be mind boggling.

[opeldean]

Originally Posted by jvandyke It does matter though because if I opt for an electric valve and I'm wrong and I can't control temp then I'll be grumpy.

For what its worth,if you want heat...peel up the insulation around the tranny tunnel ..now that is heat!

I have flushed my heater core and put in a new valve...i dont get much heat at full on..i cant see that there is much to be gained by a valve with variable adjustment...

although...my old mantas had great heat...you could tweek the valve just a bit and you could control it precisely

[kwilford]

Originally Posted by jvandyke Okay, but even if the volume drops won't the core soon be as hot with say 5 gallons/minute running through of 200 degree coolant as it will with 7 gallons per minute of 200 degree coolant. I'm just not convinced that a moderate change in volume, once things are all heated up is going to change the temp coming through the vents in the car but I readily admit I don't know squat about this stuff. It does matter though because if I opt for an electric valve and I'm wrong and I can't control temp then I'll be grumpy.

The coolant flow rate through the core matters. A LOT. The heater core simply transfers heat from the coolant into the air blowing through the core. If you don't restrict the coolant flow, FAR too much heat is available to be transfered to the air. Simply, you wil have no control of the temperature.

Think of your engine and radiator. If it didn't matter how much coolant was pumped through the engine you would need a pretty tiny water pump.

Heat transfer is a function of:
1) approach temperatures (the difference between the two objects, in this case the coolant and air temperatures)
2) the heat transfer coefficient (the "effectiveness" of how heat is conducted, or convected, from one object to the other)
3) mass flow rate (how MUCH heat can be brought in, and taken away)

This is the "volume" of heat, NOT the temperature. To heat up the air inside your cold car, you need LOTS of heat transfer. Not just a small amount of very hot air, but LOTS of VERY hot air. So lots of hot coolant, and lots of air to be heated.

Conversely, if you just need a "bit" of heat, you REALLY need to be able to control the coolant flow (since you have NO control of the coolant temperature, as that is determined by the engine thermostat), and to a lesser degree, the amount of air flow (for example, by the fan speed).

The GT heater system also includes an air bypass (ie cold air) around the heater core as the temperature control is slid towards the cold side, effectively reducing the heat transfer from the core, making the temperature control more effective. You'll see this when you take your heater core box apart, which you will have to do to repair your squeaky fan.

The cables are a bit complicated, but when set up, work VERY well. One controls the heater valve with a second cable on the same slider controlling the bypass air. The other controls the position of the air flow (to the floor, to the defrost ducts, or a combination). Oh, and pay heed to the advice to look closely at your heater slide control. They are almost AWAYS broken, thereby eliminating the proper function of either the valve, bypass or position. I was able to fix mine with an aluminum plate and some pop rivets, but usually they are too damaged to repair. The OGTS aluminum replacement is a bit pricey, but well worth the $

HTH