Was taking an evening ride with the wife in the cool of the evening the other night and heat was pouring out from under the drivers side dash, but not the passengers side.

It was hot enough to where I felt like I put on a fresh pair of ironed pants.

I'm getting ready to pull the duct work and fix the air leaks so I can get the A/C working.
This does not seem like a leaking duct, and it seems to be coming from the tunnel area.

Any ideas guys?

Ralph

 

I would wait until dark and put some kind of light under the hood in the engine bay in front of the fire wall and look under the dash to see if there is any light comming through the fire wall. There could some deterioated grommets letting heat through and this would show which gromeits are letting heat through. You should also check the rubber boot under the shift console and leather boot. They will split and when they do, it feels like a fan blowing oven heat all over you. GOOD LUCK IN YOUR SEARCH.

 

when i was replacing the insulation under the carpet
i placed a spot light under the car, shut the shed and found a possible source of hot air getting into the cabin.
looked like a disco inside the car
under the dash, just below where the steering column comes thru the firewall, there are holes where rubber plugs go that hold the carpet from falling down
well they were missing, so 3 - 3/8" holes letting in hot engine air
got some rubber grommets and plugged them shut.

now i'll have to unplug the heater hose, it's totally different in there now, almost too cold

 

I'll check it out

R~

 

Had the same problem with mine. Mechanic said it was the (don't quote me on the name of the part) the hot water bypass valve. it runs off of vacuum and mine had the peice the hose attaches too completely broke off. It supposedly, to my understanding, is also connected to the a.c. When the valve doesn't open it redirects the heat inside. I'm not a mechanic so someone else may be able to better explain. I know in the summer wearing shorts, the heat coming in made my calf feel like it was on fire. Hope it helps

 

Thanks but I already put in a manual shut off valve in it.

Ralph

 

My '68 gets hot too under the dash next to the trans tunnel while my
foot is on the accelerator.
My heater core was already disconencted when I purchased the car
last fall.
The '68's used a hot water shut off valve as well.
It was activated by vacuum similar to your headlights and wipers in my case.
Even though it was shut during A/C or venting it is my understanding passive heat convexted past the shut off valve.
Thus heat was still being felt at the heater core inside.
Ideally if you live in a warm climate or drive seasonally you could completely disconnect the heater core.
It takes 1 more heating element out of the cooling equation.
I have a 427 so it gets hot. I'd imagine later c-3's with the smog
equipt gotta run hot too.
I'm currently assessing my options and will work to cool my interior.
I would like to run my factory A/C without it having to work so hard
battling heat.
To be continued
Marshal

 

Thanks Marshal135

I have the reflective rubber backed stuff on the floor and a heavy backed cut pile carpet.
I'm thinking it's still coming from the heater, EVEN THOUGH I have the shut off in the pressure side of the heater hose, that's the smaller hose.

Maybe I should just make a loop and by pass the heater core all together.

It would be quick and easy to do. and it would Eliminate the heater altogether that way.
Between that and shinning a light from below hopefully I'll get some answers.
I get it out of the paint shop on Monday and will start working on it then.

Hot August nights Reno is just around the corner and I'll need A/C for sure.

Ralph

 

Ralph,
I'm convinced that with by passing the heater core you will notice a difference.
Mine is just looped with a short piece of heater hose ran from the water pump directly to the intake manifold nipple.
Leave enough hose to have a natural curve so it doesn't kink.
Make sure it is not near the A/C fan belt.
If you have insulation and are still getting that much cabin heat
I'd suspect the heater core is radiating hot water heat past your ducts
into the cocpit. Plus the A/C has to fight this to overcompensate for heat.
I think it just puts extra uncalled for strain on the A/C system.
Let us know how you make out.
Good luck with your new paint job.
Mine is due for a strip and spray too.
Marshal

 

Thanks mine was egged a while back and insurance is picking up the tab.
State Farm $45.00 a month $100.00 deductible. $0.00 deductible on Vandalism.

Ralph

 

Where are those little miscreatins when I need em
I'd trade off a drive by egging for a new Safari yellow
paint job
Sorry to hear that, the little aholes have no idea what it takes to keep
these vintage cars going w/o any extra help.
A good caneing sounds in order
Marshal

 

Ralph, I like you, and many others have gone through this. Through many searches on this site, I have found information that I have used to elimintate heat coming through the vents.


#1: Article written by Vettefixr, regarding the use of strip caulk at the seams inside the pass fender, behind the kickpanel flapper door. A sh#tload of engine bay and exhaust heat gets in through the deteriorated seams and drain hole.

#2 If seal is missing at the point of entry of heater core hoses at firewall, stuff some foam up in there

#3 There is a drain hole at the bottom of the ac box at the firewall. I took the cap from a soda bottle, drilled one hole in it and glued it over the opening

#4 I used strip caulk to close off the entry points of the high and low pressure ac lines going into the ac box

#5 I had exhaust leaks at the connection of the manifolds to the exhaust. Replaced donuts. Mmmmmm donuts

#6. Found various gaps on driver side where fender and firewall meet. Used strip caulk and [temporarily] insulated tape to block these openings to the wiper/air plenum. In a few weeks, I intend to glass over the larger gaps.

#7 I have a new hood gasket to seal the back of the hood but havent put it on yet.

#8 You already have the shutoff valve.

I didnt do these all at the same time, and each one made a little difference along the way, but I have now driven the car a few times with all of these changes made, and so far I am pleased with the results. I would say 90% of the heat has been eliminated even after lengthy drives. Some marginally warm air will enter after a while, but NOTHING like the heat that used to POUR in.

Keep in mind that my ac doesnt work, and even at that, so far I have been comfortable on the past couple of nice summer days Ive driven the car

 

I saw her on Friday right at quitting time, she is still the prettiest girl in town. They will buff her out on Monday and I'll take her home if all goes well.
I'm amazed on how much I love my Stingray. I have a real nice 1990 with a 6 speed that just sits.
I have 300 hours in her now and only a few more kinks left to iron out.

Remember, the paint was finished in January so it was not a pleasant experience finding her that way.
I don't think caneing is appropriate in this situation.
Does the word "Electrodes" stir up any images?

Ralph

 

Thanks for the list there Big Block Dave.
List are my friend.
I have about 10 days to get the heat stopped and the A/C working
Then it's off to Hot Aug. Nights Reno.

Ralph