skinsfan

Hello all, I am new to this forum but I have been a Vette owner for 10 years. I have a '77 L82. When I bought it everything worked execpt the heater. It seems as if the hose had been bypassed from the heater core. I live in FL so I do not need a heater. Here is my problem: when I drive the car for a while I feel the normal heat that comes from the floor panel, but I have intense heat coming in from the floor vents. When my A/C was working around six years ago the heat would come in when the A/C was off. Now its always blowing hot air.. is there any way to stop this hot air from coming in without doing a complete A/C repair?

Lino

terryrudy

I had the same problem, so I just took the heater fuse out for now until I can spend some more time on the interior. Problem solved. Not the best solution, but at least makes the car driveable for me now. The biggest loss for me (I live in CA so I never used heater either) is the defroster which I do need occasionally.
-terry

Scott78

I have the same problem, mine is from a bad hood seal(soon to be replaced). Another source is the fresh air door not shutting. This door is in a bad place, right at the base of the passenger fender to firewall area. But check that you are getting vacumm to the actuators to close the door. Oh and welcome to the forum.

Scott

Paul 75 L82

I don't know about a 79 but my 75 has a fresh air vent on the passenger kick panel. This was a sorce of heat so I removed the panel cover and duct taped this vent closed. Made alot of difference.

Chris@VetteFinders

So you are saying that the coolant is not even getting into the heater core?

ZD75blue

i too would like to know the answer to this... mine gets awful hot too, tho last test drive was mid summer... i doubt i would notice it now... brrr

rdrman

Mine was hot too! I replaced the hood seal,redid all the heater doors and by-passed the heater core...found that the foam collar on the trany was missing. ended up putting ceramic insullatioc on the trans tunnel on the inside [underneth the radio] and it cooled things down quite a bit so it's more drivable now even in the heat

Warp70

I just disconnected the vaccume hoses from the fresh air vents, plugged em and then I stuffed an old t'shirt in from of the door and replaced the kick pannels :cheers:

78RedShark

If you can get an insulation kit, that might do the trick...however some from the vendors don't cover the entire area where the accelerator and brake pedals are.

I too have the same problem in my car...there are little holes that have formed from where the original hoses and tubes from under the hood connected with fuse box and steering column on the driver side. These holes were originally sealed with a sealant...which over time dries out and flakes away, exposing areas where heat from the engine comes directly in contact with your feet.

See if you have any such holes, and try re-sealing them with a good sealant. It might help out...as well as some insulation under the carpet on both the driver and passenger sides.

I know that heat...I lost 20 lbs. this summer in my car...screw SuperFitness! :lol:

skinsfan

Thanks to all that replied..I will look at these suggestions and try to correct the problem... stay tuned!

skinsfan

Update: I took out the fuse and the blower no longer pushes the hot air into the floor of the car. Unfortunately, the hot air is still coming in. My car is in the body shop for a face lift (new paint job!!!), so I can not try anymore fixes for now. I suspect that one of the vacume powered doors in the ac system is malfunctioning. Does anyone have a schematic of this ac vacume system(77L82Auto). Is there an EASY fix for this...or do I have to pull out the dash and the center console?

rdrman

When I had my center dash out and consel out I replaced all the vaccum lines the rotary vac. switch and sealed all the leaky ducts,some vac. lines were disconnected[pulled out] some were leaking.Also make sure that the seal on the hood is there otherwise you will suck in hot air from the engine compartment..PS while your in the dash replace all the lights that you can while its opened up :cheers:

TJKirby82CE

I have the same problem. From my research I have found that my fresh air vents did not open when the a/c was on. All other times they were open letting in hot air. I would like to know if the vacume closes the doors or if no vacmue causes the door to close. Maybe our fresh air doors are working properly but Im thinking about disconnecting mine and shutting them for good.-Travis Fresno 110+ June July Aug..ugh!

Larry B.

I CAN tell you that my 69 has all of the original blankets and insulators. It is a Big block with Stock manifolds.NO headers. All of the heater /A/C stuff works and my car is never hot. I did have a 71 that had the heat problem so I know what you are talking about. :D :D

Clink69

:lol: :lol:

Duct Tape: Best tool out there isn't it! Mine are stuffed with rags.

:flag

skinsfan

That is my question exactly. When the ac was on the fresh air vent would shut, and when off it woud open thus letting in the HEAT. I do not want to duct tape the system because I would like to have the ac working .. I guess I am going to have to pull out the dash (LOOK OF HORROR ON MY FACE AS I TYPE) and trouble shoot all the ac doors. :(
I will post an update as soon as I get my car back.

GWHITE75

I have a 75, which I have just removed the whole system and replaced it with a Vintage Air system, but as I retrace my retrofit, the vent you speak of at the bottom on the passengers side is for return air, when you switch to the max air setting on the car. Two bellows operate, when this is selected. One at the inlet to the blower fan, which closes off outside air, and the other in the oval port down by the passengers feet that opens to allow air recirculation. So it is not an actual vent that allows air in. The box housing the evaporator core and heater core on the firewall, has little, if no, insulation, so radiated heat will eventually find its way into the inside of the unit. As you operate your car, the blower runs at a low RPM to allow air changes. This will always create a small amount of heat through the vents during warmer times of the year. If you have modified the motor with headers/hood with holes, where hot air can get to the blower inlet and have not checked your vacuum system, seals around the A/C system and insulation, more heat will be allowed into the compartment. Two other things: If the heater core has the hoses eliminated, but the core is still installed, make sure the old water/antifreeze if flushed out as it will eat the core up and eventually leak. Look for holes in the firewall. I had a couple of holes in my firewall, allowing engine compartment air to enter the compartment unabated, due to weathering of the rubber grommets/plugs used to hold the firewall insulation on the inside of the compartment. Small holes were present. I did not experience any of these problems when the car was stock and newer, so time and modifications can adversely affect the ability to keep heat out of the compartment. If you have any of the deflectors, seals, panels or insulators missing, radiated heat from the headers can increase heat to the fiberglass and heat the compartment as well.