Cockpit Heat !!!
Thread Starter
Racer
Joined: Oct 2009
Posts: 441
Likes: 2
From: San Antonio TX
Cockpit Heat !!!
I disconnected the heater hoses to the firewall , but still getting ALOT of heat in the car cab from under dash , putting the vent on does not help & rolling the windows down seems to draw thru even more hot air ....I'm roastin' my nuts here ...Help ?
Racer
Joined: Aug 2004
Posts: 419
Likes: 4
From: Lewisville TX
Your problem is probably not enough insulation between you and the engine bay.
A lot of us have used reflectix (HVAC insulation) or dynamat to insulate our cars.
Check this link out:
http://home.comcast.net/~vettfixr/page14.htm
A lot of us have used reflectix (HVAC insulation) or dynamat to insulate our cars.
Check this link out:
http://home.comcast.net/~vettfixr/page14.htm
Drifting
Joined: May 2006
Posts: 1,480
Likes: 2
From: Circleville Ohio
Vader vette
Made all the diff in the world .
My motor Mount was bad and let my fan blade hit one of the little nuts that hold the shrouding and it flexed my fan alright so Jegs was handy put on the flex fan, switched over to electric last season It was a great fan but did not keep the cabin cool so I put the flex fan back on .
If it brakes and goes through the hood Ill need A new hood. Have seen the same flex fan on Dragsters at the spring nants in Ohio.
Burning Brakes
Joined: Jun 2006
Posts: 809
Likes: 1
From: Mass
I'd suggest reflectix, you can buy it at home depot and it's cheap and it works well. Dynamat won't reduce the heat in the cabin but it's used for limiting vibrations/sound in the cabin (It works well for stereos)
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,117
From: Crossville TN
There are several sources of extra heat getting into the passenger compartment. Exhaust heat: inadequate insulation on the floorboard area; engine heat: inadequate insulation on the firewall and old, compressed gasket/seal at the rear of the hood. When that seal dries out and compresses, there is a gap between the seal and body rail so that engine heat blows by and right into the air intake for the passenger compartment: replace that hood seal. Heater dumping unwanted heat into passenger compartment: malfunctioning heater/ac controls; water shut-off valve inoperable or not getting the vacuum line signal to turn OFF when required. There are others, but those are the 'biggies'. Your main problem sounds like a 'bad' hood seal.
Safety Car
Joined: Apr 2007
Posts: 4,435
Likes: 9
From: Kalamazoo Mi
before you go putting more insulation in your car, check to see if you have bad hvac controls. i was getting heat pouring in from under my dash, turns out it was the hvac control cable. the zip tie holding it in place had come off, so it felt like it was working, when it wasnt, and it was sending all the heat to my feet.
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Le Mans Master
Joined: Jun 2005
Posts: 5,447
Likes: 3
From: Syracuse NY
Just get these and the rest of your passenger compartment will seem fine.
http://forums.corvetteforum.com/c3-g...t-heaters.html
http://forums.corvetteforum.com/c3-g...t-heaters.html
Racer
Joined: Nov 2009
Posts: 384
Likes: 2
From: Tulsa OK
On second thought I'll just post it so everyone can read it:
"Like most of you I've battled the problem of cockpit heat. I think
I've finally found a problem in my 74 that may be common to a lot of
C3s and which may cause heat to come in to the cockpit no matter how much
insulation or sealing is done to the heat/AC system. Over time I've
noticed that I always got an "engine" smell in the cockpit. I figured
it was air coming out of the hood and being drawn into the heating system
through the air intake in the wiper trough or air leaking into the system
through the heater box. I put a wiper cover on earlier this year and I
could see that the hood sealed really well in this area so this
shouldn't cause a problem with air leakage past the gasket. Since I
pulled my heat/AC system out last winter and resealed everything I
discounted this as a cause for heat leakage also. When doing the heating
system I also installed a shutoff valve for the coolant. I also insulated
my entire cabin so I'm not getting heat through the floorboards or the
body. This left the air intake on the system as a possible source. I
removed the right hand dash pad and kickpanel which exposed the flapper
mechanism for the inside/outside air control. I removed the vacuum motor
and flapper mechanism by unbolting the two bolts that hold the motor,
moving it out of the way, and unhinging the flapper. This is done by
pulling down the top spring loaded pin, pushing the door into the
fenderwell and twisting it so that it can be removed from the inside of
the car. I then started the engine with the hood closed and the heat/AC
off. I felt hot air coming into the plenum from the engine compartment.
This plenum is secured with the same adhesive that holds the rest of our
body panels in place and like those the adhesive will dry and crack over
time. Anyone who has dealt with stress cracks on the fenders can attest to
this. Remember also that air leaking into this plenum will be coming
directly off the exhaust system and with headers the problem is
exaggerated. To seal this plenum I used windshield sealing caulk. You can
get this at your local parts store for around $5 a roll. I used the caulk
to seal around the entire perimeter of the plenum, or as much as my arm
would reach since you're working through the flapper hole. The most
important areas to seal are the forward and lower area since that's
where the majority of the heat will come from. The rear area is sealed
against the forward door jam and really shouldn't leak hot air. After
doing this I repeated the test with the engine running and felt no heat
entering the cockpit. I reinstalled everything to complete the job.
I've only driven the car twice since then but I can tell you that there
was a vast improvement. I took the car to work on a day when the
temperature hit about 85 degrees. Before the fix I would have had to have
the AC running or the heat would have been unbearable in the footwells and
even worse with the t-tops off. I ran the car home that day with the
t-tops off and the footwells were no hotter than the rest of the car.
I've also noticed that the AC tends to run a little cooler by not
having to fight the heat coming into the system. So far I also haven't
had that "engine" smell anymore. I'm hoping that as I use the car
more, in different situations, I'll be able to report more benefits
from this fix but until then I thought I'd give a heads up to everyone.
For details on the cockpit insulation go to my website. You'll see the
article on insulation and also what you have to remove to reseal the
heater box.
UPDATE 9/12/03: Since posting this topic in the C3 forum over a year ago
I've had time to live with this fix and I can tell you it's
completely eliminated the footwell heat common to C3s. I've also
recommended this fix to others who have had similar success. One tip that
I left out in the original post was to put a soda straw through the bottom
of the plenum until it sticks out below the rocker panel. Seal the plenum
all around the straw and when you've completed the sealing pull the
straw out through the bottom of the rocker panel. This leaves a drain
hole that will channel water in the event that it enters the plenum.
Other than that it's an afternoon fix that really pays off. Good luck."
"Like most of you I've battled the problem of cockpit heat. I think
I've finally found a problem in my 74 that may be common to a lot of
C3s and which may cause heat to come in to the cockpit no matter how much
insulation or sealing is done to the heat/AC system. Over time I've
noticed that I always got an "engine" smell in the cockpit. I figured
it was air coming out of the hood and being drawn into the heating system
through the air intake in the wiper trough or air leaking into the system
through the heater box. I put a wiper cover on earlier this year and I
could see that the hood sealed really well in this area so this
shouldn't cause a problem with air leakage past the gasket. Since I
pulled my heat/AC system out last winter and resealed everything I
discounted this as a cause for heat leakage also. When doing the heating
system I also installed a shutoff valve for the coolant. I also insulated
my entire cabin so I'm not getting heat through the floorboards or the
body. This left the air intake on the system as a possible source. I
removed the right hand dash pad and kickpanel which exposed the flapper
mechanism for the inside/outside air control. I removed the vacuum motor
and flapper mechanism by unbolting the two bolts that hold the motor,
moving it out of the way, and unhinging the flapper. This is done by
pulling down the top spring loaded pin, pushing the door into the
fenderwell and twisting it so that it can be removed from the inside of
the car. I then started the engine with the hood closed and the heat/AC
off. I felt hot air coming into the plenum from the engine compartment.
This plenum is secured with the same adhesive that holds the rest of our
body panels in place and like those the adhesive will dry and crack over
time. Anyone who has dealt with stress cracks on the fenders can attest to
this. Remember also that air leaking into this plenum will be coming
directly off the exhaust system and with headers the problem is
exaggerated. To seal this plenum I used windshield sealing caulk. You can
get this at your local parts store for around $5 a roll. I used the caulk
to seal around the entire perimeter of the plenum, or as much as my arm
would reach since you're working through the flapper hole. The most
important areas to seal are the forward and lower area since that's
where the majority of the heat will come from. The rear area is sealed
against the forward door jam and really shouldn't leak hot air. After
doing this I repeated the test with the engine running and felt no heat
entering the cockpit. I reinstalled everything to complete the job.
I've only driven the car twice since then but I can tell you that there
was a vast improvement. I took the car to work on a day when the
temperature hit about 85 degrees. Before the fix I would have had to have
the AC running or the heat would have been unbearable in the footwells and
even worse with the t-tops off. I ran the car home that day with the
t-tops off and the footwells were no hotter than the rest of the car.
I've also noticed that the AC tends to run a little cooler by not
having to fight the heat coming into the system. So far I also haven't
had that "engine" smell anymore. I'm hoping that as I use the car
more, in different situations, I'll be able to report more benefits
from this fix but until then I thought I'd give a heads up to everyone.
For details on the cockpit insulation go to my website. You'll see the
article on insulation and also what you have to remove to reseal the
heater box.
UPDATE 9/12/03: Since posting this topic in the C3 forum over a year ago
I've had time to live with this fix and I can tell you it's
completely eliminated the footwell heat common to C3s. I've also
recommended this fix to others who have had similar success. One tip that
I left out in the original post was to put a soda straw through the bottom
of the plenum until it sticks out below the rocker panel. Seal the plenum
all around the straw and when you've completed the sealing pull the
straw out through the bottom of the rocker panel. This leaves a drain
hole that will channel water in the event that it enters the plenum.
Other than that it's an afternoon fix that really pays off. Good luck."
Advanced
Joined: Sep 2007
Posts: 55
Likes: 0
From: Buffalo NY
Wow !!! Great story, if you put that to video you could make some money. Better yet.... youtube it.You would have a lot of hits.
I suffered from the heat for ten years. I replaced hot water valves etc. all to no avail. However your problem describes mine to a tee (engine fumes and heat) It's Easter Sunday and if I wouldn't catch hell from the wife, I'd try it right now////Question how long and how difficult?
Thanks for sharing it with us
Carl
I suffered from the heat for ten years. I replaced hot water valves etc. all to no avail. However your problem describes mine to a tee (engine fumes and heat) It's Easter Sunday and if I wouldn't catch hell from the wife, I'd try it right now////Question how long and how difficult?
Thanks for sharing it with us
Carl
On second thought I'll just post it so everyone can read it:
"Like most of you I've battled the problem of cockpit heat. I think
I've finally found a problem in my 74 that may be common to a lot of
C3s and which may cause heat to come in to the cockpit no matter how much
insulation or sealing is done to the heat/AC system. Over time I've
noticed that I always got an "engine" smell in the cockpit. I figured
it was air coming out of the hood and being drawn into the heating system
through the air intake in the wiper trough or air leaking into the system
through the heater box. I put a wiper cover on earlier this year and I
could see that the hood sealed really well in this area so this
shouldn't cause a problem with air leakage past the gasket. Since I
pulled my heat/AC system out last winter and resealed everything I
discounted this as a cause for heat leakage also. When doing the heating
system I also installed a shutoff valve for the coolant. I also insulated
my entire cabin so I'm not getting heat through the floorboards or the
body. This left the air intake on the system as a possible source. I
removed the right hand dash pad and kickpanel which exposed the flapper
mechanism for the inside/outside air control. I removed the vacuum motor
and flapper mechanism by unbolting the two bolts that hold the motor,
moving it out of the way, and unhinging the flapper. This is done by
pulling down the top spring loaded pin, pushing the door into the
fenderwell and twisting it so that it can be removed from the inside of
the car. I then started the engine with the hood closed and the heat/AC
off. I felt hot air coming into the plenum from the engine compartment.
This plenum is secured with the same adhesive that holds the rest of our
body panels in place and like those the adhesive will dry and crack over
time. Anyone who has dealt with stress cracks on the fenders can attest to
this. Remember also that air leaking into this plenum will be coming
directly off the exhaust system and with headers the problem is
exaggerated. To seal this plenum I used windshield sealing caulk. You can
get this at your local parts store for around $5 a roll. I used the caulk
to seal around the entire perimeter of the plenum, or as much as my arm
would reach since you're working through the flapper hole. The most
important areas to seal are the forward and lower area since that's
where the majority of the heat will come from. The rear area is sealed
against the forward door jam and really shouldn't leak hot air. After
doing this I repeated the test with the engine running and felt no heat
entering the cockpit. I reinstalled everything to complete the job.
I've only driven the car twice since then but I can tell you that there
was a vast improvement. I took the car to work on a day when the
temperature hit about 85 degrees. Before the fix I would have had to have
the AC running or the heat would have been unbearable in the footwells and
even worse with the t-tops off. I ran the car home that day with the
t-tops off and the footwells were no hotter than the rest of the car.
I've also noticed that the AC tends to run a little cooler by not
having to fight the heat coming into the system. So far I also haven't
had that "engine" smell anymore. I'm hoping that as I use the car
more, in different situations, I'll be able to report more benefits
from this fix but until then I thought I'd give a heads up to everyone.
For details on the cockpit insulation go to my website. You'll see the
article on insulation and also what you have to remove to reseal the
heater box.
UPDATE 9/12/03: Since posting this topic in the C3 forum over a year ago
I've had time to live with this fix and I can tell you it's
completely eliminated the footwell heat common to C3s. I've also
recommended this fix to others who have had similar success. One tip that
I left out in the original post was to put a soda straw through the bottom
of the plenum until it sticks out below the rocker panel. Seal the plenum
all around the straw and when you've completed the sealing pull the
straw out through the bottom of the rocker panel. This leaves a drain
hole that will channel water in the event that it enters the plenum.
Other than that it's an afternoon fix that really pays off. Good luck."
"Like most of you I've battled the problem of cockpit heat. I think
I've finally found a problem in my 74 that may be common to a lot of
C3s and which may cause heat to come in to the cockpit no matter how much
insulation or sealing is done to the heat/AC system. Over time I've
noticed that I always got an "engine" smell in the cockpit. I figured
it was air coming out of the hood and being drawn into the heating system
through the air intake in the wiper trough or air leaking into the system
through the heater box. I put a wiper cover on earlier this year and I
could see that the hood sealed really well in this area so this
shouldn't cause a problem with air leakage past the gasket. Since I
pulled my heat/AC system out last winter and resealed everything I
discounted this as a cause for heat leakage also. When doing the heating
system I also installed a shutoff valve for the coolant. I also insulated
my entire cabin so I'm not getting heat through the floorboards or the
body. This left the air intake on the system as a possible source. I
removed the right hand dash pad and kickpanel which exposed the flapper
mechanism for the inside/outside air control. I removed the vacuum motor
and flapper mechanism by unbolting the two bolts that hold the motor,
moving it out of the way, and unhinging the flapper. This is done by
pulling down the top spring loaded pin, pushing the door into the
fenderwell and twisting it so that it can be removed from the inside of
the car. I then started the engine with the hood closed and the heat/AC
off. I felt hot air coming into the plenum from the engine compartment.
This plenum is secured with the same adhesive that holds the rest of our
body panels in place and like those the adhesive will dry and crack over
time. Anyone who has dealt with stress cracks on the fenders can attest to
this. Remember also that air leaking into this plenum will be coming
directly off the exhaust system and with headers the problem is
exaggerated. To seal this plenum I used windshield sealing caulk. You can
get this at your local parts store for around $5 a roll. I used the caulk
to seal around the entire perimeter of the plenum, or as much as my arm
would reach since you're working through the flapper hole. The most
important areas to seal are the forward and lower area since that's
where the majority of the heat will come from. The rear area is sealed
against the forward door jam and really shouldn't leak hot air. After
doing this I repeated the test with the engine running and felt no heat
entering the cockpit. I reinstalled everything to complete the job.
I've only driven the car twice since then but I can tell you that there
was a vast improvement. I took the car to work on a day when the
temperature hit about 85 degrees. Before the fix I would have had to have
the AC running or the heat would have been unbearable in the footwells and
even worse with the t-tops off. I ran the car home that day with the
t-tops off and the footwells were no hotter than the rest of the car.
I've also noticed that the AC tends to run a little cooler by not
having to fight the heat coming into the system. So far I also haven't
had that "engine" smell anymore. I'm hoping that as I use the car
more, in different situations, I'll be able to report more benefits
from this fix but until then I thought I'd give a heads up to everyone.
For details on the cockpit insulation go to my website. You'll see the
article on insulation and also what you have to remove to reseal the
heater box.
UPDATE 9/12/03: Since posting this topic in the C3 forum over a year ago
I've had time to live with this fix and I can tell you it's
completely eliminated the footwell heat common to C3s. I've also
recommended this fix to others who have had similar success. One tip that
I left out in the original post was to put a soda straw through the bottom
of the plenum until it sticks out below the rocker panel. Seal the plenum
all around the straw and when you've completed the sealing pull the
straw out through the bottom of the rocker panel. This leaves a drain
hole that will channel water in the event that it enters the plenum.
Other than that it's an afternoon fix that really pays off. Good luck."
Racer
Joined: Nov 2009
Posts: 384
Likes: 2
From: Tulsa OK
Carl,
It's not my story, I'm just reposting it. The original post should be available by searching the archives, which is probably a good idea. Then we can ask him if he still thinks this fix is as great as initially thought.
Anyone else have experience with sealing the plenum from the vent "flapper" hole?
It's not my story, I'm just reposting it. The original post should be available by searching the archives, which is probably a good idea. Then we can ask him if he still thinks this fix is as great as initially thought.
Anyone else have experience with sealing the plenum from the vent "flapper" hole?
Melting Slicks
Joined: Jul 2009
Posts: 2,091
Likes: 40
Heel & Toe
Joined: Apr 2010
Posts: 18
Likes: 0
From: Florida
I've got a ton of heat too, like everyone else it seems, but what caught my eye about this fix was the "engine fumes" smell. I get a fair amount of that and can even smell it on my clothes after driving for a little while, it's like I've been running a lawn mower all day. I've even noticed a little drowsyness, like I'm inhaling carbon monoxide at non-lethal levels...if I was a canary, I might be dead. Anyway, I found the original thread and here's a link.
Has anyone got good pictures of what this fix is all about? I've read it a few times and can't really understand what to look for.
http://forums.corvetteforum.com/c3-t...hing-here.html
Has anyone got good pictures of what this fix is all about? I've read it a few times and can't really understand what to look for.
http://forums.corvetteforum.com/c3-t...hing-here.html
Heel & Toe
Joined: Apr 2010
Posts: 18
Likes: 0
From: Florida
got photos of plenum area
Got a nice response from the original tech tip poster on sealing the passenger side plenum and he sent 2 photos for clarification of the area he sealed through the flapper door. They are the same photo, but one has a yellow highlighted line showing where to seal.
[IMG]
[/IMG]
[IMG]
[/IMG]
[IMG]
[/IMG][IMG]
[/IMG]
Racer
Joined: Nov 2009
Posts: 384
Likes: 2
From: Tulsa OK
[QUOTE=FL1971coupe;1573750980]Got a nice response from the original tech tip poster on sealing the passenger side plenum and he sent 2 photos for clarification of the area he sealed through the flapper door. They are the same photo, but one has a yellow highlighted line showing where to seal.
Great!
can you post his response/update as well?
thanks
Fred
Great!
can you post his response/update as well?
thanks
Fred