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Heater Bypass Faulty??

 
  #1  
Old 06-22-2010, 03:04 PM
kdexter
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Heater Bypass Faulty??

Just installed the valve(74809),tied into white line..I got it at advance auto.. I didnt see any huge temp difference.. What gives.. I started truck with ac on max setting went on parts run 60 miles at 70mph.. with the fan setting on 2nd notch I had readings of 46deg. I changed it to the a/c setting, temps showed 46-48.. switched over to bi-level setting temps stayed around 46-48deg. I moved the temp setting while in max to hottest setting it blew warm air.. switched to heater/defrost and ran me out of cab.. ok now the return trip.. I put white line back to factory config.. shutting off the valve had these temps.. 46-48 in max position a/c setting 48deg.. bi-level 48-52deg..kinda stumped as to whats going on..the valve is working as far as pulling the actuator in on max setting and out in all other settings?????
 
  #2  
Old 06-22-2010, 03:20 PM
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That doesnt sound right. You should see at least a 5 deg difference.
When you say the actuator is moving when in max setting I assume you mean the actuator on the valve? Maybe a stuck valve then?
Its also possible it could be a vacuum leak causing the actuator to move, but not close the valve completely.
 
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Old 06-22-2010, 03:30 PM
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yes thats what I mean the Vac. Actuator.. I have checked that its fully in on the max setting, also just noticed that the hoses from the heater core to the valve are hot.. I know its been said that there is no wrong way to install it but could it be..I dont see how.. after it cools down i'm going to remove it and check it out..
 
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Old 06-22-2010, 03:38 PM
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May be a faulty valve.
I think your on the right track checking it off of the truck.


I have a little different set up, but it drops the air temp at the vent by ~8 deg.
It takes a few minutes to drop down, but you should see a difference.
 
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Old 06-22-2010, 07:14 PM
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Got the valve off and I hooked it up to the garden hose.. sure enough bad valve.. no matter what position you put the hoses or lever water will flow full force thru the valve.. going after new one.. different manufacture this time..
 
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Old 06-22-2010, 07:32 PM
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i think this may be the case with mine too. Mine started out feeling nice and cold, but lately i cant tell a difference. i'm gonna ops check mine too. let us know waht you find.
 
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Old 06-22-2010, 09:04 PM
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heater bypass update

took the valve(kool Air) back to advance auto,they didn't have a replacement gave me my money back.. drove over to o'reily's picked one up from them (Murray) same number..Still looked like the kool air brand made in mexico... I decided to hook it up to water hose before putting on and wow what a difference..almost no flow out of it.. i'd say maybe 5% flow if that when in closed position..anyhow got it installed and with the truck warmed up at idle i'm getting a reading of 41deg out of vent.BURRRR.. Sweeeet!!!!!! will see how it does driving tomorrow in the 100 Heat..now its time
 
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Old 06-23-2010, 07:59 AM
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Thats awesome man, glad you got it worked out.
You will definitely notice a difference when its that hot outside!
 
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Old 06-23-2010, 09:03 AM
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Originally Posted by kdexter View Post
took the valve(kool Air) back to advance auto,they didn't have a replacement gave me my money back.. drove over to o'reily's picked one up from them (Murray) same number..Still looked like the kool air brand made in mexico... I decided to hook it up to water hose before putting on and wow what a difference..almost no flow out of it.. i'd say maybe 5% flow if that when in closed position..anyhow got it installed and with the truck warmed up at idle i'm getting a reading of 41deg out of vent.BURRRR.. Sweeeet!!!!!! will see how it does driving tomorrow in the 100 Heat..now its time
Do you happen to have the Murray part # from O'Reilly's? And then it's a vacume T, some vacume line and 4 hose clamps for the heater hoses?

Thanks...
 
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Old 07-02-2010, 12:04 PM
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Originally Posted by kdexter View Post
took the valve(kool Air) back to advance auto,they didn't have a replacement gave me my money back.. drove over to o'reily's picked one up from them (Murray) same number..Still looked like the kool air brand made in mexico... I decided to hook it up to water hose before putting on and wow what a difference..almost no flow out of it.. i'd say maybe 5% flow if that when in closed position..anyhow got it installed and with the truck warmed up at idle i'm getting a reading of 41deg out of vent.BURRRR.. Sweeeet!!!!!! will see how it does driving tomorrow in the 100 Heat..now its time
We just did this to my friends 7.3 f250.
We then put another valve on the other heater hose and noticed even more of a drop in temp.
 
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Old 07-02-2010, 12:25 PM
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FWIW - I installed one on my 1990 F250 (460 gas), and it made no difference in the warm air that came from the dash when you didn't use the A/C. I bought a cable-operated one, and a small universal choke cable, and just mounted the cable **** under the dash. No vacuum logic issues or 'I wonder if the valve is open or shut?' questions. In a perfect world, I would prefer a vacuum operated valve with just the right logic, but in the same way that I prefer manual hubs (I've had it up to here with the auto-hubs), I like the simplicity and positive nature of a cable-operated valve.
 
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Old 07-02-2010, 12:31 PM
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If you put it on the white line in our trucks, it only shuts the valve off in Max AC. If you put it on the red line, it shuts it off in vent, AC, & Max AC. Maybe a couple other settings, but I sometimes want heat when I run Vent or AC, so I left it on the white line. You can find out real easy if the valve is on or off. Turn your temp to full hot -- any warm or hot air coming out means it's open, or partially open...
 
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Old 07-02-2010, 04:25 PM
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It should be closed all the time while in max A/C right? I just tested what you said Izzy and i can feel warm air. Does this mean i have a bad valve or a vacuum leak?
 
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Old 07-02-2010, 05:03 PM
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This is a great mod. I'm looking forward to doing this for my f250 soon.
 
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Old 07-02-2010, 06:48 PM
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Originally Posted by clintusaf View Post
It should be closed all the time while in max A/C right? I just tested what you said Izzy and i can feel warm air. Does this mean i have a bad valve or a vacuum leak?
Probably a bad vacuum valve......
 

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