Astro-Ventilation Question
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,591
Likes: 53
From: Central MN
Astro-Ventilation Question
About two weeks ago, I purchased a '70 L-46 no a/c Corvette. It seems like no matter how I adjust the ventilation, it just blows hot air. The heater core has been replaced and all the "pluming" is correct. Is this normal or is there a trick to get the system to blow non-heated air?
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Common problem. The air in the plenum from where the Astro-Ventilation sources, is good and warm from the engine, exhaust, and tranny.
Not sure there's a fix for non-air cars. Many completely block off the vent(s) behind the kick panels where a lot of heat comes. And there are different ideas about further insulating the ****-pit but that's not the problem you're tackling.
But I don't understand why Vettes suffer heat more than other cars with the same system. Perhaps less room under the hood,..don't know.
Not sure there's a fix for non-air cars. Many completely block off the vent(s) behind the kick panels where a lot of heat comes. And there are different ideas about further insulating the ****-pit but that's not the problem you're tackling.
But I don't understand why Vettes suffer heat more than other cars with the same system. Perhaps less room under the hood,..don't know.
Safety Car
Joined: Feb 2006
Posts: 3,557
Likes: 0
From: Ridgeway VA
I have a '70 that was originally air but the guy before me took all the
AC parts off. I have done most of what has been recommended - insulate under carpet, put a valve on heater hoses so hot water doesn't
come into the heater core, and many more. But, my '70 is souped and
runs great but after an hour of driving my steering column is hot to the
touch as are the bezels. Vettes are "hot" in many ways!
AC parts off. I have done most of what has been recommended - insulate under carpet, put a valve on heater hoses so hot water doesn't
come into the heater core, and many more. But, my '70 is souped and
runs great but after an hour of driving my steering column is hot to the
touch as are the bezels. Vettes are "hot" in many ways!
Racer
Joined: Jan 2007
Posts: 385
Likes: 3
From: RTP NC
About two weeks ago, I purchased a '70 L-46 no a/c Corvette. It seems like no matter how I adjust the ventilation, it just blows hot air. The heater core has been replaced and all the "pluming" is correct. Is this normal or is there a trick to get the system to blow non-heated air?
I had heat coming in from the vents as well. When the engine got up in Temp I could really feel in pouring in. I saw where another member had used something called "Refletix" to insulate his car (under the carpet). I had planned on using that so I went to the local "Lowes Hardware Store" and bought a roll... something like $22.00. I cut a piece of that and wrapped the box in the engine that houses the fan unit (my car is a A/C car). That fixed the heat coming in issue for me!!! I assume that the air being sucked into that box from the cowl was being warmed up because the box has no insulation..... Anyway, whatever it was I now have no more heat coming in when the setting is on VENT.
With the setting on MAX A/C I still have heat but I suspect that reason is because I have no insulator down in the car and no carpet as well.
Below is another Link where PhotoVette discusses something similar...
http://forums.corvetteforum.com/show....php?t=1715489
Good Luck,
Pro
Joined: May 2002
Posts: 518
Likes: 17
Check:
a) That the Blend Door Cable is properly adjusted and actually turning off the heat.
b) The Hood Seal at the cowl end of the hood is critical, make sure it's there and sealing, otherwise engine heat goes right down the plenum.
c) All HVAC seals etc.
For those with AC cars a good mod is a Compressor Clutch on/off switch. This allows you to use the AC Normal path without the Compressor Clutch activated for fresh air flow (much better than the Vent path).
a) That the Blend Door Cable is properly adjusted and actually turning off the heat.
b) The Hood Seal at the cowl end of the hood is critical, make sure it's there and sealing, otherwise engine heat goes right down the plenum.
c) All HVAC seals etc.
For those with AC cars a good mod is a Compressor Clutch on/off switch. This allows you to use the AC Normal path without the Compressor Clutch activated for fresh air flow (much better than the Vent path).
About two weeks ago, I purchased a '70 L-46 no a/c Corvette. It seems like no matter how I adjust the ventilation, it just blows hot air. The heater core has been replaced and all the "pluming" is correct. Is this normal or is there a trick to get the system to blow non-heated air?
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,591
Likes: 53
From: Central MN
Everybody...........Thanks for your replies and suggestions. The great thing about this forum is we can all learn from each other.
As part of my light restoration process, I'm going to replace the carpet. Well, as long as I'm in there, I plan on putting down some of that heat reflective stuff that Corvette Central sells. Hopefully, this will help cool down the **** pit.
PETKAH..........Great suggestion about the shut off valves to the heater core. Is it necessary to put shut off valves on both hoses or is just one sufficient?
As part of my light restoration process, I'm going to replace the carpet. Well, as long as I'm in there, I plan on putting down some of that heat reflective stuff that Corvette Central sells. Hopefully, this will help cool down the **** pit.
PETKAH..........Great suggestion about the shut off valves to the heater core. Is it necessary to put shut off valves on both hoses or is just one sufficient?
Safety Car
Joined: Feb 2006
Posts: 3,557
Likes: 0
From: Ridgeway VA
I have a shut off valve in each hose although I've seem some with just
one. (Use the search function and you will get great details on how to
do.) I also have side pipes because I like the look & sound. (You can
get a bolt on kit for about $900 with fiberglass covers like I have - you
won't get burns.) Other reasons why hot -- cast iron manifold, needs
a double firewall, more tranny tunnel insulation, and needs to have cool
air come in from the front of the engine - not behind. OK - the real reason it's hot - and I'm trying to say this carefully so I don't get Forum
Flamed - In my daily driver I have a 3.2 - now, if you compare this to
a stock Vette it would be about 7.2. Is the engine too big for the car -
of course not it's too much fun to drive.
one. (Use the search function and you will get great details on how to
do.) I also have side pipes because I like the look & sound. (You can
get a bolt on kit for about $900 with fiberglass covers like I have - you
won't get burns.) Other reasons why hot -- cast iron manifold, needs
a double firewall, more tranny tunnel insulation, and needs to have cool
air come in from the front of the engine - not behind. OK - the real reason it's hot - and I'm trying to say this carefully so I don't get Forum
Flamed - In my daily driver I have a 3.2 - now, if you compare this to
a stock Vette it would be about 7.2. Is the engine too big for the car -
of course not it's too much fun to drive.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Safety Car
Joined: Sep 1999
Posts: 4,930
Likes: 11
From: AnyTown NJ
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Check:
a) That the Blend Door Cable is properly adjusted and actually turning off the heat.
b) The Hood Seal at the cowl end of the hood is critical, make sure it's there and sealing, otherwise engine heat goes right down the plenum.
c) All HVAC seals etc.
For those with AC cars a good mod is a Compressor Clutch on/off switch. This allows you to use the AC Normal path without the Compressor Clutch activated for fresh air flow (much better than the Vent path).
a) That the Blend Door Cable is properly adjusted and actually turning off the heat.
b) The Hood Seal at the cowl end of the hood is critical, make sure it's there and sealing, otherwise engine heat goes right down the plenum.
c) All HVAC seals etc.
For those with AC cars a good mod is a Compressor Clutch on/off switch. This allows you to use the AC Normal path without the Compressor Clutch activated for fresh air flow (much better than the Vent path).
Especially the adjustment of the air distribution door.
Check this thread out for some ideas.
http://home.comcast.net/~chadwick.ro...entilation.htm
