Interior heat unbearable 80+degree days

[Racer57]

70 383cu Shaker Cuda 4 speed

Engine runs 185-195 degrees

Driver side heat is almost too much. Passenger side is exceptable and probably normal.

New carpet with dynamat and reflextic. Rubber flap covering shifter hole in floor with only a slit for shifter to poke through. Area above carpet has 2 layers of reflextic. Shaker to hood seal appears to be tight along with the seal around hood vent area. Heater water line is turned off. Exhaust pipes wrapped under driver and passenger compartment area.
If I open vent during city driving its like turning on blast furnace and if I stick hand out window near A pillar I can feel heat. While I drive Wife will do her best to feel around to find hot air flow, but can't find any. There is no factory style insulation in the car. Only reflextic which when you touch it, is no where near hot enough to be causing issues.  I feel like the shaker seal isn't working properly and allowing hot air to come out of the hood, then travel to the vents into the car. But, the seal is new and seems to be compressed all around. 

Is there something I'm missing ?

[70 Challenger Lover]

Are you running headers?

[Racer57]

Stock HP manifolds

[Headjam]

Is it related to your heater box not functioning properly? Try bypassing your heater core and see if that is your problem. Just connect the inlet and outlet hoses going to your heater core.

[GoodysGotaCuda]

Is it related to your heater box not functioning properly? Try bypassing your heater core and see if that is your problem. Just connect the inlet and outlet hoses going to your heater core.

I would probably investigate this as well to ensure the heater valve is working.


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[Racer57]

Water line has valve in engine compartment and is turned off.

[GoodysGotaCuda]

Water line has valve in engine compartment and is turned off.

How did you confirm that the valve handle is actually closing off flow and isn't broken?



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[mopar jack]

I had hot air coming from the driver vent and the steering column. Check that the firewall seal is not dipping down right over the wiper motor. It is a weak spot and I see a lot of cars that are. Pic attached. Also make sure you have a seal in the steering column as hot air will definitely enter there.

[Racer57]

I had hot air coming from the driver vent and the steering column. Check that the firewall seal is not dipping down right over the wiper motor. It is a weak spot and I see a lot of cars that are. Pic attached. Also make sure you have a seal in the steering column as hot air will definitely enter there.

Thats something that I forgot to mention in my original post. I have wrapped reflextic around the steering column inside and out and it helped a little.  I'm going to check the firewall seal again. In fact, while typing this I happen to think that I might smear some grease on it and the shaker seal so I can find out if there is gaps.

[1 Wild R/T]

The standard test back in my tech days was a bunch of strips of paper laid over the seal, close the hood/trunk lid/door then try pulling the strips.... You'll know immediately where theres tension on the seal & where there's no tension....

[hemicap]

I have heat blowing out the vents and can't stop it. 93 here today, it's not good. Which way on the valve is supposed to be off?

[Racer57]

I have heat blowing out the vents and can't stop it. 93 here today, it's not good. Which way on the valve is supposed to be off?

I have one in the engine compartment. Its a brass valve that I bought at the hardware store and is on the line that sends water TO the heater core. I painted it flat black so it blends in a little better.