Need help with A/C in '77
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
Need help with A/C in '77
so my parents had a new compressor installed in my vette while i was gone for a month. the stupid compressor locked up, and it was a year old...anyway, so i have new parts installed and have it all charged up. i can feel that it's trying to blow cold air out of the vents. it just doesn't work well enough to cool it down in the cab. it's charged with 134a. i have a new r4 compressor. i even removed the evaporator box a month ago, cleaned everything out and got some putty stuff to seal the box when i reinstalled it. my heater core is disconnected as of right now. i just completely bypassed it. yesterday i decided to check the tubes under the hood. i drove my car for a while and checked it out. they were luke-warm. are there any other suggestions of what i can do to fix this? this is what i would like to do in the near future:
1. install a c4 fan
2. install sound and heat barrier under my carpet and console
3. get some adhesive heat barrier to insulate the evap box.
this will help to make my car quieter as well as cooler. is there anything else i need to do? should i use r12 rather than 134a?
thanks, andrew
1. install a c4 fan
2. install sound and heat barrier under my carpet and console
3. get some adhesive heat barrier to insulate the evap box.
this will help to make my car quieter as well as cooler. is there anything else i need to do? should i use r12 rather than 134a?
thanks, andrew
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
It's hard to say what the problem is unless you tell us more. If the replaced compressor froze, the system should have been flushed, for example. Other questions are; did you vacuum the system before adding freon, did you switch from R12 to R134a, what are your pressure readings now, how much freon did you add. Answers to these questions will help. As far as making any changes to the car such as insulation, etc., I would hold off until you get the a/c right. You should be able to get the air temp from the vents down to the low 40 degree area. 
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
It's hard to say what the problem is unless you tell us more. If the replaced compressor froze, the system should have been flushed, for example. Other questions are; did you vacuum the system before adding freon, did you switch from R12 to R134a, what are your pressure readings now, how much freon did you add. Answers to these questions will help. As far as making any changes to the car such as insulation, etc., I would hold off until you get the a/c right. You should be able to get the air temp from the vents down to the low 40 degree area.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Did you change to the proper oil for R134A? Actually when this job is done, most suggest replacing the hose(s) and all o-rings but neither of these will create your problem at this point.
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
EDIT:
There was something wrong with my gauge. It read 80 psi with the system off and 30 psi when i had the A/C turned on. I'm pretty sure the compressor has 134a oil in it. it came with no oil, and my mechanic added 134a stuff.
Last edited by andylmusic76; Aug 29, 2007 at 04:44 PM.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
The best way is with an electronic leak detector if you have access to one. Another way is adding a dye to the system but if the leak is in an inaccessible place, such as the evaporator, you won't see it. If you put several cans of freon in the system and it now only show 5 lbs. of pressure, you have a major leak(s). FYI, when the system is pumped down with a vacuum pump, the gauges should be left on for several minutes (actually I leave mine on over night) to see if there is a lose of vacuum. If you lose vacuum, you're gonna lose freon.
As a side note, if a/c repair work is not done properly, a lot of time and $ can be lost, not to mention the possibility of personal injury.
As a side note, if a/c repair work is not done properly, a lot of time and $ can be lost, not to mention the possibility of personal injury.
Last edited by Jud Chapin; Aug 29, 2007 at 05:00 PM.
Drifting
Joined: Jan 2004
Posts: 1,991
Likes: 3
From: Piscataway NJ
EDIT:
There was something wrong with my gauge. It read 80 psi with the system off and 30 psi when i had the A/C turned on. I'm pretty sure the compressor has 134a oil in it. it came with no oil, and my mechanic added 134a stuff.[/QUOTE]
Nothing wrong with the gauge. You were reading standing pressure with the system off. And then went to 30 with the system on.
There was something wrong with my gauge. It read 80 psi with the system off and 30 psi when i had the A/C turned on. I'm pretty sure the compressor has 134a oil in it. it came with no oil, and my mechanic added 134a stuff.[/QUOTE]
Nothing wrong with the gauge. You were reading standing pressure with the system off. And then went to 30 with the system on.
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Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
i hooked up a pressure gauge and just found out that i had less than 5 psi in the system. i think i may have a leak. where and how should i check for this?
EDIT:
There was something wrong with my gauge. It read 80 psi with the system off and 30 psi when i had the A/C turned on. I'm pretty sure the compressor has 134a oil in it. it came with no oil, and my mechanic added 134a stuff.
EDIT:
There was something wrong with my gauge. It read 80 psi with the system off and 30 psi when i had the A/C turned on. I'm pretty sure the compressor has 134a oil in it. it came with no oil, and my mechanic added 134a stuff.
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
so i got to check it. i had about 25 psi of 134a, so i did some researc on the net and anyway i added between 50-52 psi, and the car got so much cooler! to tell you the truth it really isn't bad, even for florida! but i don't want it to be as good as new. i want it to be better. i'm pretty sure it gets really cool. now what i'm going to focus on is to install a c4 fan and maybe insulate the cab and firewall. if anyone has any tips, please let me know
has anyone ever installed a c4 fan?
has anyone ever installed a c4 fan?
