I have an 84 Camaro Z28. I bought it as a project car and it came w/o the HVAC unit. I mean EVERYTHING is gone. No Accumulator, Evaporator, Orifice tube/Expansion valve, Condensor or Compressor. I believe it was being turned into a drag car(hint: the Cragar drag tires). Anyway while its running the temp in the cabin gets EXTREMELY hot like 10+ degrees above outside temp(and I'm in Texas!) All the heat is coming through the defrost and fogging the window while I drive. I need help finding the problem and fixing it!

The pic is of all thats left of the HVAC system.

-KDot

 

Evaporator appears to be there.

 

if any underhood air is getting around the AC unit will heat up the inside of the car. also look for any holes in the AC Unit- it's not unheard of for people to knock holes in it next to the engine when they are installing an engine or changing spark plugs or whatever, and that box is right next to the hot exhaust manifold...

i don't know if the AC cars are the same as my non AC car- or if mine's screwed up somehow- but i've always got hot air coming out of the little vents in the side of the center console right next to the shifter... doesn't matter where the temp lever is placed, it always blows hot.. my solution was to put some black duct tape over the vents.. also look for any open holes or gaps in the firewall- i used to have a bunch of hot air from under the hood rolling in and heating up my feet as i drove it so i temporarily plugged a couple of holes with some paper towels from a gas station when i was in Texas last summer and the heat became unbearable.

 

I notice today that if I turn the HVAC system on it will blow out heat. Which have me thinking maybe the heat that's coming out the defrost vent and making the cabin so hot is just coming from the engine?

Do anyone know how to check this theory?

 

 

Wait.

Its mid-July, and you are in Texas.

And you want to know why its hotter inside a thirdgen with no A/C than it is outside? Its a wonder its not way more than a ten-degree differential. If any of the floorboard insulation or carpet is missing, you are basically driving a rolling pressure-cooker.

There are about two days out of the year where you can run such a car in Texas without being uncomfortably hot. Those days are January 31, and February 1.

 

my car was reasonably comfortable in Texas last summer- even when stuck in traffic on I35 in Austin when it was 110 degrees outside.. it's a factory non AC car with t tops and a black interior and an exterior that the previous owner spray painted black..

 

Did anybody look at the picture? The heater core is there. There is a radiator hose running to it.

Try this, unhook the heater hose and loop it around bypassing the heater core. I bet that hot air stops. I had the exact same thing. Thought it was normal that hot air was blowing in from somewhere. After I put a ball valve in line with the heater core, that hot air stopped.

Go give the loop a try. Its free and I put money on it that it works.

 

Also ensure that the hood seal is in place and functional. Air is pulled into the system from the cowl. The seal prevents hot engine air and all of it's associated smells and vapors from entering the system.