I own a 78 vette that's so hot inside you can't drive it more than an hour before your feet are roasted. This isn't just heat through the floor, you can feel the heat blowing in the area between the floor and the dash. I have rerouted the heater lines to make sure I am not getting heat off the heater core.

Does anyone have any ideas how or where to look for probable firewall leaks. I have tried a quartz light in the engine compartment, but no light shows through. I have found a small leak around the stearing rod, but it is not very large.

I can also be reached at hl@datasync.com.

I am also posting this in the interior forum for additional exposure.

have the carpets ever been changed? sometimes owners change them and throw away the heat barrier thats under the carpet.

Another thing you can check is the rubber gasket around the hood.
This gasket prevents some of the heat coming from the engine compartment into the interior. I never knew such a rubber seal exisited until someone else told me about it...

The carpet have been replaced and I am fairly sure the heat barrier has been installed. My problem is not a rising heat from the floor, it's a blowing (air movement) problem. It's like the engine heat is being blown into the cockpit on both sides. Almost like a vent was open some where or a seal was missing. I've been wondering why the kick panels have loovers. In other cars the loovers aided in bringing in fresh air to the interior. But my vette doesn't appear to have a vent. Thanks for the responce--Darrell

What gasket around the hood! Maybe that's a large part of the problem. Thanks--Darrell

Don't you have any WAWA'S near you??
They sell ICE

also did you remember to roll down the windows? that sometimes makes a difference.

My interior was also blowing warmer air. I have a shut off valve installed on the line to the heater core. Now that it is warm, I shut off the valve so there is no flow to the heater core and voila, my interior is cooler. Not sure if this is the same problem you are having.

Definately do what fla vette said, install a shut off valve in your heater line. Check out the other posts on this site. Do a search for heater valves or heater or something like that. Probably located in heating and cooling. Auto Parts Giant web site sells them for 6 or 7 bucks. Worth their weight in gold.

This 'gasket' is simply a long tubular black rubber seal which looks similar to your door seals. It's fits in the grove on the upper end of the hood and wraps around like a U shape. When the hood is closed, it will seal between the hood and that area where your windshield wipers are. The gasket isn't going to prevent the interior from getting hot but it should help a bit.

Recently replaced my heater core and found a HUGE source of hot air. Between the heater core and the interior air box is a heavy metal flapper. The flapper is connected to the heater control swing arm that is found behind the glove box. Around the edge of this flapper is a rubber seal (of which there is no replacement currently available).
One corner (about 1" x 1") of this rubber seal was completely rotted away. I was able to wrap the flapper in saran wrap, pull it shut tightly and use silicone to build up the edge of the housing to block the open area. This made a BIG difference in the amount of air that was being pushed into the car while moving.
Unfortunatly, the only way to get to this piece is with a heater core replacement procedure and we all know how many 'you might as wells' you can come up with when doing this job.
Short of doing this procedure, the heater core shut-off will probably get you the greatest result. You might also check the heater control cable (that goes to the above mentioned arm) to make sure that the flapper is being shut off completly when the heater control is in the 'cold' position. There is a plastic turnbuckle just behind the radio on passenger side (behind the leg console cover).
Hope that helps!
Ed