76 vette air question
Race Director
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From: Charlotte NC
DUB
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76 vette air
YES..I have a lot of ideas of what can be wrong...BUT...take it to someone who knows A/C. Unless you do know about it.... and if you did...you would not be asking..... because you better BE CAREFUL in doing what you are doing because the high side can get WAY too high and you actually cause more of a problem than if you took it to a professional. Not knowing if it is R-12 or 134A...and if it in a Corvette that WAS R-12 but converted to 134A...where you DO NOT put the same amount of freon in it.
DUB
DUB
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From: Charlotte NC
IF the air was not blowing hard...adding more freon will not change that.
Adding more 134a freon into a system can be dangerous due to IF the system called for 3.25 lbs of R12....you DO NOT put 3.25 lbs of 134a into it.
AS for the air not blowing hard....it can easily be. The foam seals that seal off the junctions in your ducting system are worn out and air is escaping at these junctions.
Also...there can be a lot of leaves and debris BLOCKING the front of your evaporator core...thus...reducing the air being able to flow through it. I just replaced an evaporator core in a 1972..and the amount of leaves in front of it was a JOKE.
I have an air flow meter where I can record what the air speed coming out of the center duct is before I start and what it is when I am done. And it also lets me know how hot/cold the air is coming out of the vent also.
DUB
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1976 corvette air
[QUOTE=DUB;1592416227]For what this is worth to you.
IF the air was not blowing hard...adding more freon will not change that.
Adding more 134a freon into a system can be dangerous due to IF the system called for 3.25 lbs of R12....you DO NOT put 3.25 lbs of 134a into it.
AS for the air not blowing hard....it can easily be. The foam seals that seal off the junctions in your ducting system are worn out and air is escaping at these junctions.
Also...there can be a lot of leaves and debris BLOCKING the front of your evaporator core...thus...reducing the air being able to flow through it. I just replaced an evaporator core in a 1972..and the amount of leaves in front of it was a JOKE.
I have an air flow meter where I can record what the air speed coming out of the center duct is before I start and what it is when I am done. And it also lets me know how hot/cold the air is coming out of the vent also.
how do i go about checking for leaves etc in front of theevaporator. do i have to take something apart to get to it.
IF the air was not blowing hard...adding more freon will not change that.
Adding more 134a freon into a system can be dangerous due to IF the system called for 3.25 lbs of R12....you DO NOT put 3.25 lbs of 134a into it.
AS for the air not blowing hard....it can easily be. The foam seals that seal off the junctions in your ducting system are worn out and air is escaping at these junctions.
Also...there can be a lot of leaves and debris BLOCKING the front of your evaporator core...thus...reducing the air being able to flow through it. I just replaced an evaporator core in a 1972..and the amount of leaves in front of it was a JOKE.
I have an air flow meter where I can record what the air speed coming out of the center duct is before I start and what it is when I am done. And it also lets me know how hot/cold the air is coming out of the vent also.
how do i go about checking for leaves etc in front of theevaporator. do i have to take something apart to get to it.
Burning Brakes
Joined: Sep 2005
Posts: 1,139
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From: B'ham Alabama
Often times, this box gets gaps / cracks opened up and all the air blows out into the hood compartment. I have used varies things to deal it up; duct tape, caulk, body seam putty, etc.
See if you have air blowing out through the gaps. That may be your problem.
Race Director
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From: Charlotte NC
DUB
Melting Slicks
Joined: Dec 2015
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From: Texas City, TX Texas
I'd also consider putting a 1984 or newer blower motor and fan on there. Real easy, lots of guys do it, all you need is a jigsaw and a piece of plywood to make a spacer. Plenty info on the forum describing it. Also, make sure the little hose that cools the blower motor is in place. I was repeatedly burning up blower motors before I knew of this.
Last edited by Richard Daugird; Jun 14, 2016 at 06:36 PM.
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Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
I'd also consider putting a 1984 or newer blower motor and fan on there. Real easy, lots of guys do it, all you need is a jigsaw and a piece of plywood to make a spacer. Plenty info on the forum describing it. Also, make sure the little hose that cools the blower motor is in place. I was repeatedly burning up blower motors before I knew of this.
I have yet to have another car where I replace the evaporator core so I know it is perfect..and try the original fan and then the later design one where I can actually read the air flow with my air flow meter. Once I do that...then I will be able to 'speak' with facts.
DUB
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1976 vette air
With the A/C blowing on high, open the hood and feel around the air box under the hood. It'll be the box in the passenger side that the A/C hoses go into. This houses the fan unit.
Often times, this box gets gaps / cracks opened up and all the air blows out into the hood compartment. I have used varies things to deal it up; duct tape, caulk, body seam putty, etc.
See if you have air blowing out through the gaps. That may be your problem.
Often times, this box gets gaps / cracks opened up and all the air blows out into the hood compartment. I have used varies things to deal it up; duct tape, caulk, body seam putty, etc.
See if you have air blowing out through the gaps. That may be your problem.
Burning Brakes
Joined: Sep 2005
Posts: 1,139
Likes: 109
From: B'ham Alabama
That is a key area where you lose your cold air and power from the blower. If you tape up / seal up those cracks, the A/C will blow much harder and feel colder. Trust me!!
