i have a 77 corvette and I have noticed that when driving, the engine heat/air comes in to the car thru the feet vents even when the temp controller (vent/heat lever) and fan is on the off position, any advice would help, thanks everyone in in advances.

 

get your ac fixed or drive with the windows down and the tops off.

 

You probably need to start with a heater hose cut off valve which will stop water from through the heater core. You probably need to go through the search section. There are probably 100 threads about the same problem. Some of the search threads will show the valve as well as talk about all of the problems and cures of hot air entering the cabin. Good luck.

 

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Sorry Ill do a search thanks for the help

 

This is the time of year when all the "MY C3 IS COOKING ME TO DEATH!!!" noobs come out of the woodwork.

Heat enters your car's cabin through several places-

(1) It spills out over the top of the engine compartment and into the cowl vent well due to a worn/ poorly sealing underhood seal (U-shaped sponge seal at the rear underside of the hood).
(2) It enters the cabin through worn-out flapper door seals in the heater/ AC box, whether the heater is on or not.
(3) It heats up the car interior because the heater valve is malfunctioning, allowing the heater core to get hot in spite of your wishes to the contrary.
(4) The heater control inside the car is leaking vacuum, preventing the heater control from working properly and allowing heat into the car in spite of the fact that the control says "OFF".

Of all these explanations, (2) is probably the most common, because it is by far the most difficult to fix, requiring that the heater/AC box be completely disassembled in order to replace the worn-out seals. As mentioned earlier, the most common band-aid fix iis to just splice a Home Depot ball valve into the 'hot' heater hose, but unless you block BOTH sides of the heater core hot water eventually finds its way into the core just by osmosis, so the only way to REALLY kill all the hot water from entering the heater core is to put a shutoff valve on both inlet and outlet heater hoses. Obviously installing shutoff valves will fix (3) and (4) as well, since you'll be shutting off the hot water.

As far as (1), just put a new seal across the back of the hood and it will prevent hot engine air from filling up the vent well, which will then allow you to actually USE the cabin vents because cool air will now flow into the cabin...

 

There is a great article by a fellow whom goes by the name Vettfixr.

Within the write up he mentions going into the passenger side kick panel and resealing areas where the fender is bonded to the firewall etc. Essentially engine heat is able to find its way into your venitlation system via these cracks (and drainage hole), and the fan is always on regardless of the switch being in the "off" position, so it just pushes all this hot air through.


I have begun working in this area and already see a difference. I have a bit more work to do in there, but it is highly likely that this is a big part of your problem.

 

dont forget the speedo/tach and wiring grommets

 

I can feel heat by my feet when I drive, I always assumed it was just engine heat from a lack of a good sealed system. However, I noticed yesterday that I think my heater comes on even though it is switched to off.

When you turn the electronics on your corvette (don't turn the key all the way to start it), are any noises being made aside from the clock? I want to say a hear a light sound of a blower, but don't know if that is normal since there is a lot of vacuum set-ups in the car.

Thanks.

 

My car does the same thing and it is the blower. I am under the impression this is normal.

 

So you feel there is no way to turn the blower off.

 

just completed this on the 82, you have a lot of good suggestions listed above. the 2 main things that worked for me was to make sure that the heater shut-off valve is working properly. Don't remember if the 77 has one or not, but if not, install a shut-off valve into the heater hose (plenty of threads on that) and the insulation added to the driver's and passenger's side floors (along with the shut-off valve working correctly) eliminated all heat coming into the cabin period. I do not get any flow at my feet or legs anymore, a pleasure to drive in the hot weather and your AC will work nore efficiently as well. I also replaced the heater core and replaced all seals around the heater box, when it was removed from the interior.

 

To begin with, when I posted an answer at the beginning of this thread, I probably used the word probably too much. I really was on some medication and now I know why I was told not to drive. But, another place to check for hot air is the shift boot. I know on the 4 speeds, there is a rubber boot under the leather boot and it's common for the rubber to be torn. This will literally feel like a fan blowing warm air on your feet.

 

There is a snip of a wire that can be done to turn this off...I havent done it yet so I cant speak from experience, but its mentioned on this forum somewhere

 

There it is!!!!!!!!!!!! Just the kind of valuable information he needs.