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Discussion Starter · #1 ·
Its way too hot inside my car. I know vettes got that heat coming in from the engine so they are a little hot inside but this feels like I have the heater set on 104 degree full blast coming out from under the dash. I know I have thermal insulation under the carpet and I just replaced the heater control on the cooling lines when I had to redo the whole system. So does it usually run that hot inside or is there something I could do to fix that problem? Its just killing me especially since all the freon leaked out of my ac
 

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Sidepipes help a lot with interior heat.. However, it's almost impossible to eliminate interior heat without a working A/C.. The previous owner of my yellow '68 Vert added thick insulation below the carpet and the car also has sidepipes.. The heat isn't all that bad BUT there is still a lot of heat coming through the shifter console (from the transmission)
 

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it's almost impossible to eliminate interior heat without a working A/C..
:agree: My floorboards get really hot in city traffic. Hiway is a different story. Warm, but not hot.

When I'm running my A/C, it's not a problem, but it's on MAX/Hi-Blower all the time (on a hot day).....
 

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The heat comes from several sources and there is not a "Majic Bullet" to cure it. There are however several things you can do to minimize it;

Thuroghly insulate the floor all the way up the firewall, I am useing Nuprene and Reflectix
Spray on insulation like Lizard skin on the underside of the floor and engine side of the firewall
Tranny insulator blanket (example)
http://www.ecklers.com/product.asp?pf_id=28835&dept_id=1628
Ceramic headers (example)
http://cgi.ebay.com/ebaymotors/CHEV...emQQcategoryZ33631QQihZ016QQitemZ260146225543

Wrap the exhaust pipes (example)
http://cgi.ebay.com/ebaymotors/DEI-...ryZ33630QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Fixing the AC is also a good idea. It suffers from a couple of problems:
1. the evap box is subject to radiated heat from the engine and exhaust. Ceramic headers and wrapped pipe will help some, but the basic problem there is still heat getting thru the fiberglass box directly into the ac system past the evaporator, heating the air before it even gets into the ducts. A solution I wish I would have thought of before I did mine is to insulate the inside of the evaporator box with Lizard skin, its a thin spray on paint that does a great job as a thermal barrier. Painting the outside of the box should do just as well.
2. Outside air leaks, make sure the outside air selector flapper works and actually closes off, mine doesn't so I am going to have to add some fiberglass to it before I put it back on.
3. Heater valve, some idiot decided that the hot water should only get shut off if you have the AC on Max so thats how the switch works. I have not gotten far enough on my restoration to address this yet, but I will. In the mean time you can use a ball shutoff valve to kill the hot water, problem solved.
4. The ac ducts were put together useing a thin foam seal that probably died 15 yrs ago, resealing the duct ends helps a lot
5. There is likely a bunch of leaves, animal fur, dead mice and decicated lizards in the evaporator box. My AIM shows a screen over the hole for the fan intake, but there never was one on my car, so while your doing the insulation on the evap box pull the fan and clean out the box
6. The duct in the center dash is supposed to be connected to the lower box, it isn't. There is a 1" gap between them behind the dash. Aluminum duct tape is a good fix, it hangs in with the heat in attics so dash heat should not be a problem.
7. A transmission cooler is a good idea no matter where you drive. There is no lower cooling number for the tranny, it should work fine at 20 below. But the max should never get close to 200*, the cooler the better, best to keep it at least down to 160* as you can

So thats what I am doing for mine, I fully expect it to be nice and cool in there even without the ac on max
 

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Discussion Starter · #6 · (Edited)
The heat comes from several sources and there is not a "Majic Bullet" to cure it. There are however several things you can do to minimize it;

Thuroghly insulate the floor all the way up the firewall, I am useing Nuprene and Reflectix
Spray on insulation like Lizard skin on the underside of the floor and engine side of the firewall
Tranny insulator blanket (example)
http://www.ecklers.com/product.asp?pf_id=28835&dept_id=1628
Ceramic headers (example)
http://cgi.ebay.com/ebaymotors/CHEV...emQQcategoryZ33631QQihZ016QQitemZ260146225543

Wrap the exhaust pipes (example)
http://cgi.ebay.com/ebaymotors/DEI-...ryZ33630QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Fixing the AC is also a good idea. It suffers from a couple of problems:
1. the evap box is subject to radiated heat from the engine and exhaust. Ceramic headers and wrapped pipe will help some, but the basic problem there is still heat getting thru the fiberglass box directly into the ac system past the evaporator, heating the air before it even gets into the ducts. A solution I wish I would have thought of before I did mine is to insulate the inside of the evaporator box with Lizard skin, its a thin spray on paint that does a great job as a thermal barrier. Painting the outside of the box should do just as well.
2. Outside air leaks, make sure the outside air selector flapper works and actually closes off, mine doesn't so I am going to have to add some fiberglass to it before I put it back on.
3. Heater valve, some idiot decided that the hot water should only get shut off if you have the AC on Max so thats how the switch works. I have not gotten far enough on my restoration to address this yet, but I will. In the mean time you can use a ball shutoff valve to kill the hot water, problem solved.
4. The ac ducts were put together useing a thin foam seal that probably died 15 yrs ago, resealing the duct ends helps a lot
5. There is likely a bunch of leaves, animal fur, dead mice and decicated lizards in the evaporator box. My AIM shows a screen over the hole for the fan intake, but there never was one on my car, so while your doing the insulation on the evap box pull the fan and clean out the box
6. The duct in the center dash is supposed to be connected to the lower box, it isn't. There is a 1" gap between them behind the dash. Aluminum duct tape is a good fix, it hangs in with the heat in attics so dash heat should not be a problem.
7. A transmission cooler is a good idea no matter where you drive. There is no lower cooling number for the tranny, it should work fine at 20 below. But the max should never get close to 200*, the cooler the better, best to keep it at least down to 160* as you can

So thats what I am doing for mine, I fully expect it to be nice and cool in there even without the ac on max
thanks this should be really helpful
 

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Discussion Starter · #7 ·
Sidepipes help a lot with interior heat.. However, it's almost impossible to eliminate interior heat without a working A/C.. The previous owner of my yellow '68 Vert added thick insulation below the carpet and the car also has sidepipes.. The heat isn't all that bad BUT there is still a lot of heat coming through the shifter console (from the transmission)
yeah thats what i had heard i plan to get those soon when the money allows
 

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Danny brought up some excellant points/cures. I can only add, if you have glass t-tops, invest in those cheap pop in headliners from Mid-America. Helped a great deal.
 

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Discussion Starter · #9 ·
Danny brought up some excellant points/cures. I can only add, if you have glass t-tops, invest in those cheap pop in headliners from Mid-America. Helped a great deal.
good idea i have some black ones that came with the car just kinda forgot about them
 

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On the fiberglass TTops you can lay in a layer of reflectix against the inside, will make a big difference
 

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HOT HOT, and more HOt. Be glad you don't have a dark colored car like mine, it doesn't help one bit. I almost always have the t-tops off when crusing. If I cant have the tops off, usually the weather is not nice enough for me to take the Vette out. In that case I'll take the 1987 Lotus Esprit, which is black, but has colder AC than my 1998 BMW 740i (which is black on black as well).:thumbsup: GOOD LUCK BUDDY!!
 

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Discussion Starter · #12 ·
HOT HOT, and more HOt. Be glad you don't have a dark colored car like mine, it doesn't help one bit. I almost always have the t-tops off when crusing. If I cant have the tops off, usually the weather is not nice enough for me to take the Vette out. In that case I'll take the 1987 Lotus Esprit, which is black, but has colder AC than my 1998 BMW 740i (which is black on black as well).:thumbsup: GOOD LUCK BUDDY!!
yeah well all i have is a caprice with a broken transmission and a 72 silverado without ac
 

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Let me tell you what I did to my HOT, HOT,HOT 82. Couldn't stand the hot cockpit anymore, so I put a shutoff valve on the heater, so that the hot fluid doesn't run thru the heater. I can open the valve in the fall so that I get heat when I want it. Works like a charm. Dropped the heat considerably. I also went up to Home Depot and purchased a couple of rolls of insulation (the silver stuff with the bubble wrap inside) and installed it under the seats and under the console, and up in the storage compartment. That made more of a difference too. The car is not all that bad now. Just a few thoughts. (Picture of the valve is in my corvette photos.)

Good Luck!

Dave
 

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Discussion Starter · #14 ·
Let me tell you what I did to my HOT, HOT,HOT 82. Couldn't stand the hot cockpit anymore, so I put a shutoff valve on the heater, so that the hot fluid doesn't run thru the heater. I can open the valve in the fall so that I get heat when I want it. Works like a charm. Dropped the heat considerably. I also went up to Home Depot and purchased a couple of rolls of insulation (the silver stuff with the bubble wrap inside) and installed it under the seats and under the console, and up in the storage compartment. That made more of a difference too. The car is not all that bad now. Just a few thoughts. (Picture of the valve is in my corvette photos.)

Good Luck!

Dave
Question and sorry if I sound stupid with this but when I redid my cooling sytem new hoses water pump and all I replaced the heater control valve with a new one. Does this device do the same thing as the shut off vavlue you put on yours? Did you remove that peice when you put your shut off vavle on?
 

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If you have a new control valve, I guess that it would do the same thing. The reason I put a separate valve on mine is that I wanted no fluid going to my heater core, thus no heat. My orig. control valve is screwed up and it was low on the priority fix list at the time. PS my a/c is not working either. Try the extra insulation, is an easy $40 fix. Just remove the seats and go for it.

Dave
 

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Discussion Starter · #16 ·
If you have a new control valve, I guess that it would do the same thing. The reason I put a separate valve on mine is that I wanted no fluid going to my heater core, thus no heat. My orig. control valve is screwed up and it was low on the priority fix list at the time. PS my a/c is not working either. Try the extra insulation, is an easy $40 fix. Just remove the seats and go for it.

Dave
yes as soon as the 104 degree weather here gets little cooler thats what i plan on doing. I put the new control valve on there but either the vacum line is messed up or that valve is defective because it seems hotter inside the car now then it was before i replaced it so i think im going to go with the shut off valve you used.
 

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yes as soon as the 104 degree weather here gets little cooler thats what i plan on doing. I put the new control valve on there but either the vacum line is messed up or that valve is defective because it seems hotter inside the car now then it was before i replaced it so i think im going to go with the shut off valve you used.
Been too long since I replaced my water valve, but as I recall, the thing should be set so when you pick it up off the shelf/bubble pack...you have to know wether when the heat is wanted if there is suction on that vac line leading to it.....so in max air...let's assume there is NO vacuum...therefore you want a valve of appropriate water diameters to not flow.....

I only put in one of them, to lazy to do two...because the engine water still comes in the back side, and warms the core over time....constant mix/circulation through that hose.....so both really need blocking...
 

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Heat in cabin

My 69 coupe has no A/C...here is another idea that works real good at footwells....the shields I have are available at ZIP (the plastic ones)...you just install 1" foil back insulation between shield and footwell..





I'm going to fit some on my 78....

Rich
 

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My 69 coupe has no A/C...here is another idea that works real good at footwells....the shields I have are available at ZIP (the plastic ones)...you just install 1" foil back insulation between shield and footwell..





I'm going to fit some on my 78....

Rich
I lkie that approach.:thumbsup:
 

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I lkie that approach.:thumbsup:
There is a huge difference between the 69 (with shields)compared to the 78 (without shields).

The idea is to stop the heat on the "heat source" side....when I was in Amboy,Ca awhile back,my footwells in the 78 were 130 F !!! The ambient air was 112 F....I got the data with my Raytek Mini Temp gun...also,ground/hwy surface themps were 150 F.....so the 78 was soaking all this heat up....(and I have heat insulation under carpet which is not good enough by itself...)

The 69 is much cooler in footwells...attributed of course to those shields/insulation...

Rich
 
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