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Heater bypass valve for EFI cars

5.9K views 17 replies 11 participants last post by  dale  
#1 ·
I am in the process of installing a heater bypass valve on my heater so that I can keep circulation going to my computers temperature sensor when I have the heat turned off.
I purchased a 95 ford ranger heater bypass valve but didn't like the way the vacuum actuator was set up. It was set up so with vacuum off hot water would circulate through the heater and with vacuum applied it would pypass the heater and circulate over the temp sensor.
I would rather have no circulation through the heater with no vacuum so I flipped the vacuum actuator 180 degrees and made an extension to the vacuum actuator linkage. Now without vacuum the hot water is not going to my heater.
I found a small 12volt solenoid at my local pick and pull and have wired it to my heater fan rotary switch.
Now when I turn on the heater fan it activates the solenoid and allows vacuum to open the circulation to my heater. When my fan is switched off the solenoid bleeds the vacuum off and the circulation is closed off to my heater but continues over the temp sensor.
 

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#4 · (Edited)
#5 ·
I have this one from Vintage Air that I have not used (new). Yours for $15 + shipping.

46115-VUH Servo
heater control valve
for Gen IV systems
 

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#6 ·
Dale that valve is no different................

Dale the valve you have for sale is no different than our cable actuated valve factory five supplies other than its electrically operated.
The 4 way I show closes off flow to the heater but still enables circulation through the tubes on top of the intake that have the temperature sensor for the computer.
 
#10 ·
Dale the valve you have for sale is no different than our cable actuated valve factory five supplies other than its electrically operated.
The 4 way I show closes off flow to the heater but still enables circulation through the tubes on top of the intake that have the temperature sensor for the computer.
Sorry, Taz. Read too fast:blush: and thought you wanted one like the pic, only with electric control. I went with the Old Air one that does exactly what you want; keeps flow to the sensor when heater is blocked-off.

Cheers, Dale
 
#8 ·
Four port Electronic Heater valve

I bought such a valve from an outfit called Thermotion but haven't yet installed it. I'm running a 4.6L DOHC and the heater has to run through the crossover from the right cylinder bank to the left. Using the kit supplied valve would cut off the flow of coolant in the off position. Check out the valve at Thermotion. Not an endorsement since I haven't installed it yet, I'm running w/o the heater in line.
 
#9 ·
I bought such a valve from an outfit called Thermotion but haven't yet installed it. I'm running a 4.6L DOHC and the heater has to run through the crossover from the right cylinder bank to the left. Using the kit supplied valve would cut off the flow of coolant in the off position. Check out the valve at Thermotion. Not an endorsement since I haven't installed it yet, I'm running w/o the heater in line.
Yes I saw that brand, but $150ish? Kinda of pricey for what it is.
 
#12 ·
I am in the process of installing a heater bypass valve on my heater so that I can keep circulation going to my computers temperature sensor when I have the heat turned off.
Sounds like you have a great idea. Good to see some inventiveness.:)

I fretted about needing a by-pass set up, to keep the computer happy, but ended up just leaving the provided Vintage Air water valve cracked open a fraction. With the vent louvers turned off, I'm not noticing any added heat in the cockpit, and the engine still runs perfectly fine. One day maybe I'll still add a by-pass..
 
#13 ·
Ranger Heater by-pass thread revival

Implemented the same solution on my MK4 with the SOHC 4.6L.
Worked great when I did my first go-karts 2 years ago. But I had a small evidence of collant leak on my tranny that I never found where it came from.

Started the engine again now that I'm almost ready to put the body on.

Had a major coolant leak from the pivot point of the valve.

I realized that the bracket I fabricated and was attached with the original two screws did not put pressure on the washer and internal gasket at the pivot point... this is where the coolant was leaking from.

Went back to the original vaccum activated switch and dremmelled out the part where the screws attached the vaccum switch and there is indeed a little round shoulder that puts pressure over the mini washer and internal gasket. That part is now sanditched btw my bracket and the by pass valve effectively securing the gasket in place...

Have to refill with coolant and try again. hopefully the gasket is not unseated the valve ruined...

Other mays run in the same situation depending how you designed you bracket.
 
#14 ·
#16 ·
I like the cable actuated one better. I get too much heat in the cockpit except on the COLD days so the cable can be pulled partly open and regulate the perfect amount of heat. The vacuum and electric ones are either off or on.
 
#17 ·
I do not believe the OAP electric is an on/off deal.

The dash switch is a rheostat labeled with a thermometer graphic suggesting it has variable settings. The wiring is too complex for a simple on/off circuit.

Have the valve installed in the hoses but not electrically connected yet.
 
#18 ·
Agree with Kevin; it can be "feathered".