Heater Issue
#1
Heater Issue
Ok , my heater blows cold air , I replaced thermostat ... that wasn't the problem . If I flip the selector from cold to hot a few times I get heat for 10 seconds then it goes cold again.... it worked fine before I put different engine in , so do you think this could be the heater core or the heater switch? You have to access heater core under dash right ?
#3
Is it an A/C car or heater only? My guess is a vacuum leak. Since engine has been out, make sure the vacuum storage ball underhood is there and connected. One side to manifold vacuum, the other goes to the HVAC control head.
Could also be the vacuum operated hot water valve at back of engine if it's an A/C car. It should stay open unless selector is in MAX A/C. That's only time it's designed to shut off water to heater core.
Could also be the vacuum operated hot water valve at back of engine if it's an A/C car. It should stay open unless selector is in MAX A/C. That's only time it's designed to shut off water to heater core.
#4
Is it an A/C car or heater only? My guess is a vacuum leak. Since engine has been out, make sure the vacuum storage ball underhood is there and connected. One side to manifold vacuum, the other goes to the HVAC control head.
Could also be the vacuum operated hot water valve at back of engine if it's an A/C car. It should stay open unless selector is in MAX A/C. That's only time it's designed to shut off water to heater core.
Could also be the vacuum operated hot water valve at back of engine if it's an A/C car. It should stay open unless selector is in MAX A/C. That's only time it's designed to shut off water to heater core.
#5
I wish I could remember if I used heater at all after putting different engine in car . I took the entire heating / AC unit out from under the hood soon after installing engine because of limited space when I was dealing with the rear spark plug and wire among other things , so I probably never tried using it ... It's kind of strange how I can get hot air to blow for a little bit if I flip from warm to cool a few times on the heater itself inside the car .
#9
I will then inspect the control head as a last resort .
#10
I think the early valves worked one way while the later valves worked opposite as raider said. So by getting an early valve it may not work right w your 72 controls.
If that is case I would order the 72 455 valve, you may need an adapter to fit in the manifold as I * think* they are different sizes
If that is case I would order the 72 455 valve, you may need an adapter to fit in the manifold as I * think* they are different sizes
#11
I think the early valves worked one way while the later valves worked opposite as raider said. So by getting an early valve it may not work right w your 72 controls.
If that is case I would order the 72 455 valve, you may need an adapter to fit in the manifold as I * think* they are different sizes
If that is case I would order the 72 455 valve, you may need an adapter to fit in the manifold as I * think* they are different sizes
#13
Thanks everyone for the input on this , it turns out that it was the heater valve . I took the old one off the 350 , put a adaptor on it , hooked all the hoses up and it works now .
#15
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