78 interior heat
Thread Starter
Intermediate
Joined: Feb 2012
Posts: 43
Likes: 0
From: Ocala FL
78 interior heat
After reading all the posting on the forum about the different way members have address this issues, this is what I am going to try. First a new gasket on the rear of the hood, I am also going to put a cover over the windshield well, and last I am going to run manifold vacumn to the A/C hot water shut off valve. The valve is closed with manifold vacumn thru the cut off switch, so what would be different between that and another cutoff valve on the same hose? I am putting this out for input or reason not to do it this way. Thanks Jerry
Pro
Joined: Feb 2012
Posts: 577
Likes: 6
After reading all the posting on the forum about the different way members have address this issues, this is what I am going to try. First a new gasket on the rear of the hood, I am also going to put a cover over the windshield well, and last I am going to run manifold vacumn to the A/C hot water shut off valve. The valve is closed with manifold vacumn thru the cut off switch, so what would be different between that and another cutoff valve on the same hose? I am putting this out for input or reason not to do it this way. Thanks Jerry
Don't forget the foam block that goes around the top of the transmission case under the tunnel. It keeps hot air from flowing down between the transmission and the body. That piece of foam alone makes a huge difference.
Race Director
Joined: Dec 2007
Posts: 14,345
Likes: 4
From: Hartselle AL
St. Jude Donor '09
In doing the hydroboost/borgeson mod, I found the rubber boot covering the clutch rod going through the firewall was completely shot. This left an ~2" open hole directly from the engine bay into the cabin. Replacement from Zip was $22 with shipping.
Just something else to look for, at least in manual trans cars.
Just something else to look for, at least in manual trans cars.
Burning Brakes
Joined: Dec 2010
Posts: 945
Likes: 10
From: Winston Salem NC
Check your speedo cable grommet too. Mine was missing. 1" hole open behind Ex. manifold.
I recommend putting down hushmat (or similar) and reflectix. They made a huge difference for me. Plus, I put in a real shut off valve on the heater core line.
I recommend putting down hushmat (or similar) and reflectix. They made a huge difference for me. Plus, I put in a real shut off valve on the heater core line.
Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
There is no advantage to adding a second water cut off valve. I would not put a cover over the wiper valley if you have the rear hood seal. It would be worth while to put a vacuum guage on the hose to the water valve. Then, move the temp switch all the way to the left (cold) and see if you can maintain vacuum. Just driving around a bit can vibrate the temp lever ever so slightly to the right off of full cold and you can loose your vacuum. There is a cable adjustment turnbuckle behind the right lower dash cover if you need to adjust.
Without spending much money the best things you can do is:
Install the foam tunnel collar as suggested ($15.00)
Assure the seals around the vents in the kick panel are sealing and not leaking hot air.
Rear hood seal
proper operation of the water valve shut off
Make sure all openings through the firewall are sealed
Make sure the heat shield under the car in the tunnel is not missing
After that you have to start spending money for things like Dynamat under the carpet.
Without spending much money the best things you can do is:
Install the foam tunnel collar as suggested ($15.00)
Assure the seals around the vents in the kick panel are sealing and not leaking hot air.
Rear hood seal
proper operation of the water valve shut off
Make sure all openings through the firewall are sealed
Make sure the heat shield under the car in the tunnel is not missing
After that you have to start spending money for things like Dynamat under the carpet.
Thread Starter
Intermediate
Joined: Feb 2012
Posts: 43
Likes: 0
From: Ocala FL
Thanks for all the inputs. I just replaced the carpet and I put the insulation kit in the car at that time. The only heat that is coming into the car is from the vent and just a little heat thru the firewall as a hold, not anyone place. The foam tunnel collar is installed and the heat shield is under the car. I will check the kick panel next. I checked the AIM and the vacumn hose diagram and it looks like the cutoff valve only get vacumn to close the heater cutoff valve when it is on max air. I will check this out with a guage to make sure that is correct and I could be wrong on that, that is the way I am looking at it. Thanks again Jerry
Thread Starter
Intermediate
Joined: Feb 2012
Posts: 43
Likes: 0
From: Ocala FL
I put on a new rear hood gasket and it help the amount of heat coming in thru the vents. I am going to work on the vent door this weekend and make sure there is no leaking there. Thanks for the help Jerry
Thread Starter
Intermediate
Joined: Feb 2012
Posts: 43
Likes: 0
From: Ocala FL
I when thru all the vent doors and they were fine. I charge the A/C with r12 and put a shut off valve in and low and behold it like a different car, I have to run the A/C on low where before it was like I did not have any A/C. The list is getting shorter and the car is looking and driving better. Thanks for all your help Jerry
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