Corvette Forum : DigitalCorvettes.com Corvette Forums banner

1 - 7 of 7 Posts

·
Mr. Casino
Joined
·
7,581 Posts
Discussion Starter #1
One design problem with my '79 is the heat buildup under the hood caused by radiant heat from the engine/headers. I have cut two vents in stock hood to allow some heat to exit from the top. This has pretty much eliminated the warm firewall and allowed the engine to cool faster when parked.

The remaining difficulty is the A/C plenum being located only inches from the engiine/headers. This gets extremely hot because there is no exterior insulation or heat shield between the two. After a short while driving with the A/C heater control on vent, hot air comes out of the ducts. If the A/C controls are off the same problem exists.

Has anyone discovered a fix for this problem or will I have to get "inventive" again?

TIA
 

·
Registered
Joined
·
84 Posts
mine was venting hot air in were the heater hoses go in there was a broken seal there and I have heard the same problem with others also finder wheel seals at top of finder can vent in hot air from the engine
 

·
Mr. Casino
Joined
·
7,581 Posts
Discussion Starter #3
clar2001 said:
mine was venting hot air in were the heater hoses go in there was a broken seal there and I have heard the same problem with others also finder wheel seals at top of finder can vent in hot air from the engine

I've have looked into those possibilities , however the heated air problem starts occuring after the engine is at operating temp. The vented air temp slowly rises over a 30 minute period which indicates to me that the vent is not pulling in engine compartment air but heating outside vent air. At these times the plenum cannot be touched because of heat.
 

·
Registered
Joined
·
84 Posts
My took about that long to heat up also , one thing was my dash was hot the stero was hot my feet got hot and you could fell hot air coming thure the dash were it shoulden't .

Good luck hope some one else will post with some help..
 

·
Registered
Joined
·
2,409 Posts
#1-install heater hose shut off valves
#2-install under carpet foiled insulation
#3-while you have the seats and carpet out, caulk any and all crevices that even hint at possible air passes
#4-reseal, or tape around the heater-a/c duct connections.

Another hint-whien you have the carpet out (and you may want to pull the dash panels too) turn off all the lights, and have a buddy shine a flash light at the firewall from the engine side. Any air pass areas will show.

Not everyone likes this idea, but I do it---take off the seals from over the suspension a-arms. This allows air to enter and pass by the headers. Personnally, I think it's worth 10-20 degrees.
 

·
Registered
Joined
·
749 Posts
when i covered my floor i used double foiled heat/sound insulation. i ,also ,discovered that the heat a/c box got hot from the exhaust manifold. i cleaned the box the best i could, then sprayed adhesive on it and cut the same heat shielding to fit. it's been on there for two summers now and we've driven hundreds of miles and no problems with it at all.
it does help keep the hot air out of and away from the box.
 

·
Registered
Joined
·
746 Posts
I found header wrap really cut down on engine compartment heat. Even after an hour on the expressways I find the heat when I open the hood alot less. This header wrap has been on the car at least 10 years without a problem
 
1 - 7 of 7 Posts
Top