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I’m having some trouble figuring out this HVAC issue. I know that a lot of things on it don’t work, but all I want is for the air blowing through the vents to not be very hot.
I replaced the vacuum shut off valve with a manual one to ensure that the heater core is certainly not heating up. But the air getting blown through the vents is still hot.
But from here, I don’t know what to do. I imagine the air is getting pulled in from the engine bay somehow.
You've turned off the hor water. That should work.
So, how is the rubber weatherstrip on the hood? Sealing to the front of the cowl area? Not Sealing and letting hot air into the wiper tray area? How are all the HVAC doors operating?
I'm not there to fix it. But that weather strip on the hood is a good place to start. Often old, hard and useless.
hot air coming in console area due to insulation collar missing at bellhousing area? Rubber boot on the clutch rod perished? The list goes on. Get to work.
Did you use TWO manual valves? Did you then completely remove the heater hoses from the engine compartment (which is at 180 degrees, BTW), or at least insulate them?
Here's @interpon's excellent guide on how to mitigate the heat issue. Unless you add coolness via A/C, the best you can do is slow it down, but there is a lot of low-hanging fruit left in your car.
I discovered a couple of issues when refurbishing the A/C on my 78, which would probably also affect your 79.
When I removed the evaporator, I could see the vent door that shuts off the air flow through the heater matrix (See photo below). I found that with the cable that controls this door adjusted as per spec, it did not actually close the door. I've adjusted it now so that it does completely close the door.
The other thing I found was that the evaporator box (through which the outside air passes) being close to the exhaust was getting very hot. Almost too hot to touch. I put some reflective sheet on this which made a big difference to the surface temperature of the box and my A/C now blows noticeably cooler.
Blue box, upper right, good example of the fan power plug I was referring to. No "off , only low. I didn't want or need to run AC, so I unplugged mine.
Great Plan!
Now you can't run the fan for vents or heater or even defroster. Cause you NEVER get caught in the rain.
And even if you feel you don't need AC. (I think your nuts).
You may at least wish to use the vents.
Great Plan!
Now you can't run the fan for vents or heater or even defroster. Cause you NEVER get caught in the rain.
And even if you feel you don't need AC. (I think your nuts).
You may at least wish to use the vents.
if that’s aimed at me, it takes 4 seconds to plug it back in, but I never did, never had an issue.
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
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Air always hot through vents
