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I have a 73 4 speed with a 454 and it doesn’t have AC (it appears to have everything for AC but no compressor for some reason)
Anyway, i’m getting a crazy amount of heat from aide of the center console about where the shifter is. It’s almost like there’s a heater vent that’s set to 100 degrees on full blast. It’s so hot I can’t rest my leg against the console. I have heard these big
blocks really heat up the drivers compartment but this seems a little excessive... I couldn’t find any threads on this so if anyone has suggestions on what I can do to fix this that would be awesome.
im also, looking for an AC compressor. Couldn’t find a write up anywhere on a 73 with 454 and some of the compressors I’ve seen online are quite pricey. Any thoughts on where I can get one from?
The only real way to bring down the heat is to pull the carpet and install Dynamat or something similar......there are other things you can do to help.....put a shutoff valve in the heater core feed line, get an Aux. trans cooler if Automatic.....do a proper tune to the engine and set timing correctly (Not GM spec) this will lower exhaust manifold temps.....
This factory shield has often been removed. You'd be surprised how much heat can be can be sucked into the cabin through the smallest opening. Sealing the tunnel in my opinion is more important than insulating. Of course Dynamat does both.
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Welcome to the no AC club. Make sure your heater control valve is working correctly and fully shutting off...you can see it behind the passenger lower dash. Helps to take the panel off. I lubed and made sure everything was working right but car still got hot. Sealed all the holes from the engine thru the firewall also. What had the most impact was putting a shutoff valve in the source line for the heater core water hose.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I but a really thick carpet backing under my carpet, i Have side exhaust which may or may not help, I had that big trans tunnel shield and I added the factory metal stone/ heat shields to the firewalls engine compartment side, and was running the ramshorn manifolds. The manual shift lever sometines got very very hot but my feet were never roasting. I always had all the vents open which blow directly on my feet. I just added ceramic coated headers whixh I hope dosnt increase the inside heat.
I would pull back your carpet and see whats under it then maybe go with something like Dynamat if the carpet is original and the backing is thin.
I didn’t even know i had one of these til shining a light up there...
mine was crooked..
op says blowing 100 like engine compartment air..bet this seal stops that vs radiantly.
i run the ac with windows down and even top off sometimes..
glass tops with sun out is hot no matter
did you take any steps to cool the cockpit down any further BEFORE doing this? Also, is it necessary to do the entire floor or just from the firewall to the seats?
Since I live in Florida, the heat in the summer is unbearable. I put Thermo Tec shielding on the floor and tunnel. I also wrapped my exhaust from the exhaust manifold to past the engine compartment. Regarding the compressor, if the car is not original, consider using a Sanden compressor. It is smaller, lighter and more efficient and can be used with R-12 or 134A. Mounting brackets are available for small and big block Corvettes. If the system has been open, at the very least you will need a new drier and a through system flush and a vacuum pull for at least an hour. Jerry
and mentioned once already. make sure no hot water getting to heater core. just put a loop hose from water pump to intake hose outlets to test.
I’ve looked into this quite a bit since getting all these great responses and i’m considering getting a manual shutoff and putting it in line to the heater core. Personally I don’t see myself needing heat in this car since the plan is to only drive it in the summer and garage all winter. But maybe as a just in case it doesn’t hurt to be able to turn it on if I feel I need it.
Buy a foot of hose. Use the same clamps over. Heat finding a path thru a hole or seam. Engine bay heating the floorboards and firewall. They are warm. You are running the heater and complaining about the heat.
I’ve looked into this quite a bit since getting all these great responses and i’m considering getting a manual shutoff and putting it in line to the heater core. Personally I don’t see myself needing heat in this car since the plan is to only drive it in the summer and garage all winter. But maybe as a just in case it doesn’t hurt to be able to turn it on if I feel I need it.
get a street valve with male threads to fit into the water pump and the other end with female threads to put the original heater hose nipple into. its clean and verey easy and works wonders
Another suggestion. Look for any air leak between engine compartment and interior. Put a drop light under the car or in engine compartment, turn off the garage lights and sit inside the car, look under the dash, you may be surprised. I was! I had 3-4 "light leaks"
Last edited by leigh1322; Jun 7, 2020 at 06:42 PM.
All good suggestions here. I have a '73 BB as well and in my case, blocking off the coolant line going to the heater core was 90% of the improvement in heat reduction. I disconnected the coolant lines from the heater core completely as I found some conduction of heat was coming from the return line to the heater core. My understanding from searching the forum and the AIM is that the '73 had no OEM water shutoff valve for the heater core, even when you activate the AC. Good luck.
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
I also noticed that putting the valve close to the firewall works better than at the front of the engine area. That long section of hose around the engine would still get hot and conduct heat into the heater core. Also I am going to put a valve on the return line as that hose also gets very warm even with no water flow. Here is the type I used....two different sizes are required for my car as the hoses are different diameter.
Interior way too hot
