AC Plenum Question
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Joined: Aug 2012
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From: Los Angeles CA
AC Plenum Question
I was having an issue where I was smelling fumes inside my cabin when I drove my car and was stopped at a light with the ac on 
. I tried to fix a few things but I ended up with more questions.
First I replaced the hood insulation so that the seal was nice and tight from the engine. Then I got under the car and used cool tape on the seam of the exhaust that was right under the AC blower fan. I also tried to tape off the fan cover from underneath to make sure there were no fumes coming from that seal.
When I looked in the cowl where the fresh air came in from I thought something looked odd. It seems to me the I don't have a plenum air cover above the fan motor?
This is a 1979.
1. The picture is of where I supposed that the plenum door should have been...am I wrong?
2. If it's not there does it mean that my car originally did not have AC?
3. Can I simply cover or seal the fresh air vent off so that my AC is always recycled from the cabin?
Thanks!
. I tried to fix a few things but I ended up with more questions.First I replaced the hood insulation so that the seal was nice and tight from the engine. Then I got under the car and used cool tape on the seam of the exhaust that was right under the AC blower fan. I also tried to tape off the fan cover from underneath to make sure there were no fumes coming from that seal.
When I looked in the cowl where the fresh air came in from I thought something looked odd. It seems to me the I don't have a plenum air cover above the fan motor?
This is a 1979.
1. The picture is of where I supposed that the plenum door should have been...am I wrong?
2. If it's not there does it mean that my car originally did not have AC?
3. Can I simply cover or seal the fresh air vent off so that my AC is always recycled from the cabin?
Thanks!
Last edited by RMMagid; Aug 7, 2012 at 10:07 PM.
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Joined: Aug 2012
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From: Los Angeles CA
Racer
Joined: Jul 2008
Posts: 353
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From: warwick rhode island
check the thread below to see how to add a plenum door.
if you just block off the plenum on that side it will also recycle the heater air.
does your car have the interior vacuum actuated door by the right kick panel?
if it is missing both the interior door and the plenum door it probably wasn't originally an a/c car.
if you just block off the plenum on that side it will also recycle the heater air.
does your car have the interior vacuum actuated door by the right kick panel?
if it is missing both the interior door and the plenum door it probably wasn't originally an a/c car.
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Thread Starter
Advanced
Joined: Aug 2012
Posts: 77
Likes: 0
From: Los Angeles CA
check the thread below to see how to add a plenum door.
if you just block off the plenum on that side it will also recycle the heater air.
does your car have the interior vacuum actuated door by the right kick panel?
if it is missing both the interior door and the plenum door it probably wasn't originally an a/c car.
if you just block off the plenum on that side it will also recycle the heater air.
does your car have the interior vacuum actuated door by the right kick panel?
if it is missing both the interior door and the plenum door it probably wasn't originally an a/c car.
Racer
Joined: Jul 2008
Posts: 353
Likes: 30
From: warwick rhode island
my apologies RMMagid. you don't need anything special to see the link. i just need to remember to include it.
http://forums.corvetteforum.com/c3-t...onversion.html
http://forums.corvetteforum.com/c3-t...onversion.html
Thread Starter
Advanced
Joined: Aug 2012
Posts: 77
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From: Los Angeles CA
my apologies RMMagid. you don't need anything special to see the link. i just need to remember to include it.
http://forums.corvetteforum.com/c3-t...onversion.html
http://forums.corvetteforum.com/c3-t...onversion.html
Melting Slicks
Joined: May 2011
Posts: 2,753
Likes: 119
From: Springfield Missouri
you say you are getting fumes?? Then you have an exhaust leak, fix it to get rid of the fumes, unless it is gas fumes, then fix that fuel leakage. If you are getting heat from the engine are, then you have openings that need new caulk or seals, fix them. Nothing from the engine bay was supposed to come into the interior area, that would be dangerious to the people sitting in there.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 27
From: Florida
The bond at the fender sometimes cracks and allows heat and bay fumes in.
some people have caulked the plenum joints from the inside thru the footwell door to seal the plenum.
With the rear hood seal replaced, it shouldn't make any difference if you seal off the plenum door area or not. You can block it off to have recirculate only, but that is usefull only when using a/c.
some people have caulked the plenum joints from the inside thru the footwell door to seal the plenum.
With the rear hood seal replaced, it shouldn't make any difference if you seal off the plenum door area or not. You can block it off to have recirculate only, but that is usefull only when using a/c.
Thread Starter
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Joined: Aug 2012
Posts: 77
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From: Los Angeles CA
The bond at the fender sometimes cracks and allows heat and bay fumes in.
some people have caulked the plenum joints from the inside thru the footwell door to seal the plenum.
With the rear hood seal replaced, it shouldn't make any difference if you seal off the plenum door area or not. You can block it off to have recirculate only, but that is usefull only when using a/c.
some people have caulked the plenum joints from the inside thru the footwell door to seal the plenum.
With the rear hood seal replaced, it shouldn't make any difference if you seal off the plenum door area or not. You can block it off to have recirculate only, but that is usefull only when using a/c.
Thread Starter
Advanced
Joined: Aug 2012
Posts: 77
Likes: 0
From: Los Angeles CA
you say you are getting fumes?? Then you have an exhaust leak, fix it to get rid of the fumes, unless it is gas fumes, then fix that fuel leakage. If you are getting heat from the engine are, then you have openings that need new caulk or seals, fix them. Nothing from the engine bay was supposed to come into the interior area, that would be dangerious to the people sitting in there.
Last edited by RMMagid; Aug 7, 2012 at 05:53 PM.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 27
From: Florida
Contrary to what most think, the only way this type of fan sucks air is thru it's center (center of drum) or the area immediately surrounding the fan plenum mount. The rest of the air box in the engine bay, with the fan running will push air into the engine bay, not suck it into the interior.
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Joined: Aug 2012
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From: Los Angeles CA
That is the ideal way of course, but try what I suggested first.
Contrary to what most think, the only way this type of fan sucks air is thru it's center (center of drum) or the area immediately surrounding the fan plenum mount. The rest of the air box in the engine bay, with the fan running will push air into the engine bay, not suck it into the interior.
Contrary to what most think, the only way this type of fan sucks air is thru it's center (center of drum) or the area immediately surrounding the fan plenum mount. The rest of the air box in the engine bay, with the fan running will push air into the engine bay, not suck it into the interior.
Thread Starter
Advanced
Joined: Aug 2012
Posts: 77
Likes: 0
From: Los Angeles CA
That is the ideal way of course, but try what I suggested first.
Contrary to what most think, the only way this type of fan sucks air is thru it's center (center of drum) or the area immediately surrounding the fan plenum mount. The rest of the air box in the engine bay, with the fan running will push air into the engine bay, not suck it into the interior.
Contrary to what most think, the only way this type of fan sucks air is thru it's center (center of drum) or the area immediately surrounding the fan plenum mount. The rest of the air box in the engine bay, with the fan running will push air into the engine bay, not suck it into the interior.
Last edited by RMMagid; Aug 7, 2012 at 10:03 PM.
Thread Starter
Advanced
Joined: Aug 2012
Posts: 77
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From: Los Angeles CA
my apologies RMMagid. you don't need anything special to see the link. i just need to remember to include it.
http://forums.corvetteforum.com/c3-t...onversion.html
http://forums.corvetteforum.com/c3-t...onversion.html
Racer
Joined: Jul 2008
Posts: 353
Likes: 30
From: warwick rhode island
there are a few on ebay. look under 'corvette plenum'.
or try these, they have various components. some seem to have the whole setup.
http://www.ebay.com/itm/NOS-1968-to-...eb41e7&vxp=mtr
these are the guys i got mine from
http://www.ebay.com/itm/Corvette-Ori...053375&vxp=mtr
http://www.ebay.com/itm/Corvette-Ori...92bcb5&vxp=mtr
http://www.ebay.com/itm/Corvette-Ori...fd57c0&vxp=mtr
http://www.ebay.com/itm/1968-82-CORV...c1ebf6&vxp=mtr
http://www.ebay.com/itm/1968-82-Chev...240791&vxp=mtr
http://www.ebay.com/itm/69-82-CORVET...074696&vxp=mtr
or try these, they have various components. some seem to have the whole setup.
http://www.ebay.com/itm/NOS-1968-to-...eb41e7&vxp=mtr
these are the guys i got mine from
http://www.ebay.com/itm/Corvette-Ori...053375&vxp=mtr
http://www.ebay.com/itm/Corvette-Ori...92bcb5&vxp=mtr
http://www.ebay.com/itm/Corvette-Ori...fd57c0&vxp=mtr
http://www.ebay.com/itm/1968-82-CORV...c1ebf6&vxp=mtr
http://www.ebay.com/itm/1968-82-Chev...240791&vxp=mtr
http://www.ebay.com/itm/69-82-CORVET...074696&vxp=mtr