I was out on the sunday night cruise with my 79 L-82, and it was getting warm in the cab (tops off, windows down) so I opened the ball vents by the doors near my feet, and the whole cruise night it was letting in nothing but really really hot air.............i have aluminized headers
is there any way to remedy this
:bb

 

I was thinking about this after you posted in my vent blocking thread.
The air that makes it to the fender sides and into the vent intakes comes
from the cowl area - wiper bay. Making sure that the hood seal is working
just forward of the cowl area would make sense. If hot air is pouring from
under the hood and into the cowl area - then that is all that will be fed into
the vents. Maybe I was a bit hasty to block off my foot vents, but I had more
reasons than just the warm air.

Also, I have seen posts on the lower cowl to fender bond not being sealed tight.
If there is a hole or gap at the bottom (near vacuum canister in 74+) then hot
air will be allowed to enter the vent area easily. I think it was Phoenix that posted this.

http://forums.corvetteforum.com/zerothread?id=502178
:seeya

 

that was a great link, i just wish I had some arrows on those pictures, I can't seem to decipher exactly what he is talking about

what I gathered was that if I pull out the vent grate under the dash, and do the whole mirror/light thing I should be able to spot a leak........correct me if I'm wrong

 

Well, tell you what, all you all can think what you want.....I got my own observations about my '72 convertible...and I can say from friend's cars as comparisons my '72 there is cooler than most....
all of them were long since converted to R134, including mine...

What I did since especially the convertibles are so loose, there is no need for air recirculation from under the hood/cowl area is just seal that flapper door shut, and take out the kick panel flapper door entirely, that makes it on recircualte all the time...fan noise is louder, so what... if you can hear that, the exhaust is too quiet...!!!

so the thing is, first seal any and ALL air leaks from firewall...period...
then seal doors shut, and make it recirculate....only....
then make damn sure the blower is up to speed, measuring the voltage across the motor directly not including any wires, just the blower motor...
and then allow only 1/2 volt drop off the general system voltage to that motor....so if the alt is putting out say 13.6 at the engine block to the output stud...the blower motor should see nothing less thean 13.1 volts directly across the motor...gotta get inventive on voltmeter lead use here, as corrosion and such tends to mess things up....30 years old does that to machinery....

NOW raise all the rugs and buy some hot water heater insulation, lay it all over the floorboards and relay the carpeting....

another thing, and this is personal, remove the duct on the driver's side from the blower to the lower left duct output on the dash...I "d rather dump all that cold air on my feet than out on my knee....
might be same for passenger....depending...like a MSO or very frequent rider/passenger...

GENE

 

Maybe I can help. If you read the post where I identified the problem you'll see that I attacked it from the inside. Recently this topic came up again and Kim Le sent me a pic asking if this was the area in question. Here's the pic he sent

What you see in the pic is the area in question with the fender removed. As you can see the bonding that holds the fender on is the only thing that creates a seal in the plenum area from which the blower draws air. Once the bonding dries out or cracks you get heat from the exhaust or engine compartment being drawn directly into the heating system with all the associated smells. If you seal it from the inside like I described you are sealing the areas that were originally bonded to the fender. If you put a light under the car and inspect inside the plenum these are the areas where light will show through and where heat will leak in. Hope this helps.

 

Also check the ground wire on the blower. A poor ground will really slow it down.

 

I have a '79 l82 that had a bad cab heat problem. I discovered that the seal around the heater core had deteriorated. Put some silicone around it, vawalla!, much improved. Hope this helps.
Stick2

 

i agree with gene...
not only did i remove the vent door on the pass side but also sealed shut the one above it...i also disconnected the vac lines going to these two doors and plugged the end of the lines...
i didnt want to remove the duct on the drivers side completely so i drilled (using a paddle bit) two additional 3/4" holes in both ducts, drivers and pass sides, so that more air is dumped onto your feet instead of your knees...
not all the air...but more on the feet and less on your knee...

 

Your problem is one universal to C3s and the group has offered some excellent suggestions. The best book on the topic is by Michael Davis and titled "A/C Strategies for the 63-82 Corvette." He goes into design limitations and possible fixes.

 

vettfixr,
Please, look at my modified picture with the re mark to confirm the fix areas.
http://www.photohost.org/gallery/sho...php?photo=1870

Thanks

 

thanks for the pic
this is something i will address soon

 

In my ride, the biggest offender seems to be the shifter tunnel. The floor is very warm but man there's a LOT of heat coming from the center. The sides of the console are warmer to the touch than the floor itself.

:mad :boxing :nonod:

 

Paul, you could have a couple of problems that would cause the console heat. First you should check the rubber boot that goes on the floor and seals the shifter. it's not unusual for the boot to tear and let engine heat come into the console area. Next check under the car and make sure you have the tunnel insulation in place. It sits above the tranny against the tunnel. Lastly you should have a thick foam rubber collar that fits between the bellhousing and the body. This gasket looks like the thick stuff you use for home window air conditioners and seals off the tunnel from engine heat. Without it the heat from the engine is free to travel down the tunnel. With it the engine heat is forced to the sides and travels below the car. Make sure all these things are correct and you tunnel heat problem should go away.

 

Al,
Did you check my post above?

 

Hi KiM
I just looked at the marked up picture . The area you have circled is part of the seal but the rear where the fender bonds to the body and makes the forward door seam is also part of the seal. What you end up with is a big box in the fender that the blower draws air from. With the flap closed the way it's shown in your picture the blower draws air from the top wiper trough area(at least on mine it does because you can feel the blower fan if you reach up) and with the door open it draws air from the inside of the car and recirculates it through the AC system when you set it on Max Air.