Interior still hot!!!
Burning Brakes
Joined: Nov 2004
Posts: 1,193
Likes: 176
From: Hillsborough NC
I am just finishing up my interior and sealing the HVAC system. Finally got the heater hoses installed and started it up to test the system.
All of the vacuum stuff works great and the flow is awesome! Wow, I wouldn't believe sealing the vents would make such a huge difference in the amount of air coming out of the vents. These things leak like siphs when the foam rots out.
Anyway, I was installing my heater hoses and found another good place for people to check to see if they are getting hot air from the engine compartment into the system. There is a foam seal that goes around the heater core inlet and outlet that seals the case. It was gone on my car when I disassembled it. If it is missing, it allows hot air from right above the exhaust to enter the system.
Just another of many possibilities.
All of the vacuum stuff works great and the flow is awesome! Wow, I wouldn't believe sealing the vents would make such a huge difference in the amount of air coming out of the vents. These things leak like siphs when the foam rots out.
Anyway, I was installing my heater hoses and found another good place for people to check to see if they are getting hot air from the engine compartment into the system. There is a foam seal that goes around the heater core inlet and outlet that seals the case. It was gone on my car when I disassembled it. If it is missing, it allows hot air from right above the exhaust to enter the system.
Just another of many possibilities.
Burning Brakes
Joined: Oct 2002
Posts: 914
Likes: 14
From: Aberdeen, Scotland
Hot feet and hot engines . .
Good luck guys! I double dynomated my internal. It made a difference, but I think its not the whole answer. I need to check better for leaks etc.
Now my engine is running hot after installing a high flow water pump and thermostat from Stewart. There's no end to the cooling problems for BB cars, driving them in Texas just isn't fun in the summer. I almost want to get rid of the old girl. Yes I am getting frustrated!
I noticed that there is no collar or shield on top of my transmission. I believe this might be a good source to insulate. Also has anyone tried teh exhaust manifold "blankets" from thermo-tec? Its a whole cover that is wired over the manifold. I don't want to remove them as they are a b*tch to get at with A/C and the little room afforded by a BBC in a vette.
carbster
Now my engine is running hot after installing a high flow water pump and thermostat from Stewart. There's no end to the cooling problems for BB cars, driving them in Texas just isn't fun in the summer. I almost want to get rid of the old girl. Yes I am getting frustrated!
I noticed that there is no collar or shield on top of my transmission. I believe this might be a good source to insulate. Also has anyone tried teh exhaust manifold "blankets" from thermo-tec? Its a whole cover that is wired over the manifold. I don't want to remove them as they are a b*tch to get at with A/C and the little room afforded by a BBC in a vette.
carbster
Thread Starter
Racer
Joined: Apr 2005
Posts: 339
Likes: 1
From: San Diego CA
Originally Posted by SLVRSHRK
Anyway, I was installing my heater hoses and found another good place for people to check to see if they are getting hot air from the engine compartment into the system. There is a foam seal that goes around the heater core inlet and outlet that seals the case. It was gone on my car when I disassembled it. If it is missing, it allows hot air from right above the exhaust to enter the system.
Just another of many possibilities.
Just another of many possibilities.
Thanks for the info...
Drifting
Joined: Apr 2002
Posts: 1,743
Likes: 37
From: Stockton Ca
Firewall Holes
When my mech pulled the dash, he found 5-6 holes 2" or bigger. That can't help. Haven't driven the car for months, in the shop. Can't wait to try it in the heat. Lake Tahoe should be a good shakedown run.
Rick
Rick
Instructor
Joined: Mar 2005
Posts: 135
Likes: 0
From: Northern NJ
I found this thread after nearly melting my sneakers the other day in my 68 vert - Thanks for some good info.
Today I put a ball valve on the top heater hose. What a difference!! Also slapped a couple of pieces of duct tape on the speedo cable hole and one on the tach cable hole. This made such an unbelievable difference.
Then I went online and ordered the bell housing collar and the exterior floor insulation panels.
Today I put a ball valve on the top heater hose. What a difference!! Also slapped a couple of pieces of duct tape on the speedo cable hole and one on the tach cable hole. This made such an unbelievable difference.
Then I went online and ordered the bell housing collar and the exterior floor insulation panels.
Burning Brakes
Joined: Nov 2004
Posts: 1,193
Likes: 176
From: Hillsborough NC
Originally Posted by 71SoCal
I had my heater core out a few months ago...I didn't find any type of foam seal anywhere! I didn't even know one existed...that's got to be a major contributor to the heat. Time to pull the heater core out again and start ordering parts.
Thanks for the info...
Thanks for the info...
If you want to reseal the whole thing, I would recommend Dr. Rebuild for the seal kit. It was very comprehensive and fit as advertised.
Good luck
Melting Slicks
Joined: Mar 2003
Posts: 2,898
Likes: 0
From: Oklahoma City Oklahoma
My 76 used to get like a brick oven inside. The OEM heatshielding was crap. I ordered some space age stuff from JC Whitney, pulled up all the carpet, and went to work. Covered everything that was coverable with this stuff, and it was a difference of night and day. I forget what it's called, but supposedly it's used by NASA. It came in a big roll (enough to do 3 Corvettes) and if I remember right, it was about $80 for the roll.
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Le Mans Master
Joined: Jul 1999
Posts: 9,206
Likes: 17
From: Sewell NJ
This thread keeps popping up so I'll add my $.02. My car was almost undrivable in any temp over 75-80 degrees. I went through all the usual suspects until I stumbled upon the fix for the air plenum that's built into the right side fender. Look at the Tech Tips section for that fix and I'm sure it will cure 90% of the problems stated here. In addition to that you have to have a shutoff valve for the heater core that you can get at any hardware store for under $10. You should also make sure all the seals in the heater box are functioning properly and that the heater box is sealed correctly to the firewall on both sides. Dr. Rebuild sells a kit for this. You can insulate the cockpit using many different materials. For details on this go to my website and look at the article on insulating the cockpit. With all of this done my 74 is no hotter than my '05 350Z roadster.
Pro
Joined: Apr 2004
Posts: 594
Likes: 0
From: Gotham City CA
Originally Posted by fugawi
is your tunnel insulation in place, and tunnel collar. when i replaced mine it cooled the interior by 20 degrees.. 
Instructor
Joined: Apr 2005
Posts: 101
Likes: 0
From: webster ny
Originally Posted by vettfixr
This thread keeps popping up so I'll add my $.02. My car was almost undrivable in any temp over 75-80 degrees. I went through all the usual suspects until I stumbled upon the fix for the air plenum that's built into the right side fender. Look at the Tech Tips section for that fix and I'm sure it will cure 90% of the problems stated here. In addition to that you have to have a shutoff valve for the heater core that you can get at any hardware store for under $10. You should also make sure all the seals in the heater box are functioning properly and that the heater box is sealed correctly to the firewall on both sides. Dr. Rebuild sells a kit for this. You can insulate the cockpit using many different materials. For details on this go to my website and look at the article on insulating the cockpit. With all of this done my 74 is no hotter than my '05 350Z roadster.
http://store.summitracing.com/
Heat Barrier, Super Insulator Mat, 48 in. x 72 in., Universal, Each
Monday $27.95
In your pictures on your website http://mywebpages.comcast.net/vettfixr/page14.htm you have the insulation on the inside of the cockpit, others have mentioned on this thread to place the insulation on the outside, to keep the heat out. Any ideas on this?
I looked under my 79, and looking at the bottom of the car, where I think the feet rest is, it doesnt look like there is any shield - just a flat fiberglass plate. Should this be shielded on the outside>
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
The early C3's (73 ??) had a metal shield attached to the exterior footwells...I have some pics...but with todays materials/adhesives,you can easily do it that way with just insulation....I'm getting ready to do mine..
Pic of "early shield...
Pic of "early shield...
Thread Starter
Racer
Joined: Apr 2005
Posts: 339
Likes: 1
From: San Diego CA
Originally Posted by lostpatrolman
I believe it was 68 and 69 that had those shields.
Originally Posted by l979Corvette
I have the same heat problem. I believe it's my heater core. The heater just doesn't turn off. Does any one think that replacing the heater core would fix the problem?
Drifting
Joined: Jun 2004
Posts: 1,881
Likes: 9
From: staten island ny
I doubt it's your heater core also, just add the ball valve on the upper hose to the core and keep it shut. You should notice a little diffrence.
I also just ordered the thermo tec self adhesive insulation from summit, I'll try it on my 79 where the earlier cars have that shielding and see if it helps. Hope it sticks to the underside of the car OK.
ESU in NY.
I also just ordered the thermo tec self adhesive insulation from summit, I'll try it on my 79 where the earlier cars have that shielding and see if it helps. Hope it sticks to the underside of the car OK.
ESU in NY.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Not me..but I'm installing it this week on the exterior footwells first...also going to seal that vent plenum(inside) on the pass side kick panel...I'm not getting high heat through ducts..My heater is disabled...