77 AC issues
Thread Starter
Racer
Joined: Feb 2008
Posts: 357
Likes: 3
From: Madisonville Kentucky
77 AC issues
Hello all,
As the heat of the summer is upon us, I want to get my 77 AC system operational. It has not worked well since I have owned the car. I am fairly certain it is low on freon, however the compressor does kick on and continue to run, but it just doesn't blow very cold. Also, there doesn't seem to be as much airflow coming out of the vents as compared to say, my 97 F150 or other vehicles. The airflow may just be the way the C3's were, I am not sure about that. I have noticed that one of the pipes under the hood gets frosted up when I run the AC. Is this more confirmation that the freon level is low? I know that is usually the case on say a home AC unit.
Obviously, if it is low, there is a leak somewhere in the system and I think I may try to have it recharged with R12 and maybe try some stop leak to see if that solves my issue.
I just recently installed a new hood liner and I have noticed a little oil spray on my hood liner right above the AC pulley. This leads me to believe I may have a leak around the main compressor shaft. Not sure if the stop leak will fix it but I figure it's the low cost option as a first attempt. If anyone has any suggestion and tips, please advise.
thanks
As the heat of the summer is upon us, I want to get my 77 AC system operational. It has not worked well since I have owned the car. I am fairly certain it is low on freon, however the compressor does kick on and continue to run, but it just doesn't blow very cold. Also, there doesn't seem to be as much airflow coming out of the vents as compared to say, my 97 F150 or other vehicles. The airflow may just be the way the C3's were, I am not sure about that. I have noticed that one of the pipes under the hood gets frosted up when I run the AC. Is this more confirmation that the freon level is low? I know that is usually the case on say a home AC unit.
Obviously, if it is low, there is a leak somewhere in the system and I think I may try to have it recharged with R12 and maybe try some stop leak to see if that solves my issue.
I just recently installed a new hood liner and I have noticed a little oil spray on my hood liner right above the AC pulley. This leads me to believe I may have a leak around the main compressor shaft. Not sure if the stop leak will fix it but I figure it's the low cost option as a first attempt. If anyone has any suggestion and tips, please advise.
thanks
Racer
Joined: Mar 2014
Posts: 316
Likes: 39
From: Machesney Park IL
I'll take a stab at this.
Oil is coming out the compressor front seal, and I'm not sure stop leak will work on a moving surface. R12 is going to be expensive, and you will need to find someone who can recycle yours, or you will have to buy a whole new charge. You are right frosting can mean a low charge, can also mean there is moisture in the system, which will mean a drain, vacuum and recharge.
Somewhere on your system ( mine is in the metal line by the coolant overflow tank and pressure switch with a blue wire and green wire) you should have a sight glass, that let's you see in the line as it is running. There should be a solid line of liquid. Any bubbles usually means low freon.
R12 is almost impossible to find, and you should not put anything else in there.
Oil is coming out the compressor front seal, and I'm not sure stop leak will work on a moving surface. R12 is going to be expensive, and you will need to find someone who can recycle yours, or you will have to buy a whole new charge. You are right frosting can mean a low charge, can also mean there is moisture in the system, which will mean a drain, vacuum and recharge.
Somewhere on your system ( mine is in the metal line by the coolant overflow tank and pressure switch with a blue wire and green wire) you should have a sight glass, that let's you see in the line as it is running. There should be a solid line of liquid. Any bubbles usually means low freon.
R12 is almost impossible to find, and you should not put anything else in there.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I think it may be your air control doors are not operating correctly inside the cabin. Or....
The heater core is supplied unless the a/c is in max. Then it is supposed to be shut off. But often the valve to shut off the hot water malfunctions so you are still fighting the hot water being supplied to the heater core and thereby hot air being supplied to the cabin to mix with the cold air being supplied by the a/c.
Either disconnect the heater core from the system and loop the water pump aoutlet to the intake manifold or put a valve in place to shut off the hot water supply to the heater core.
Frost on the cold low pressure line just means that sufficient moisture in the air is present to condense and then freeze on that line.
If the compressor continues to run then you are not low on freon. If it were low enough on freon then the compressor would cycle on and off in response to the low pressure sensor due to low freon levels.
The heater core is supplied unless the a/c is in max. Then it is supposed to be shut off. But often the valve to shut off the hot water malfunctions so you are still fighting the hot water being supplied to the heater core and thereby hot air being supplied to the cabin to mix with the cold air being supplied by the a/c.
Either disconnect the heater core from the system and loop the water pump aoutlet to the intake manifold or put a valve in place to shut off the hot water supply to the heater core.
Frost on the cold low pressure line just means that sufficient moisture in the air is present to condense and then freeze on that line.
If the compressor continues to run then you are not low on freon. If it were low enough on freon then the compressor would cycle on and off in response to the low pressure sensor due to low freon levels.
