Poor cooling in 1968 car

[Gustav4523]

I have a 1968 Buick Electra with factory AC. The cooling is not good at all. Low pressure is around 28 and hi pressure (from the comprrssor) is 110. Temp is around 70 F. Could the compressor be bad or the expansion valve? Im quite new to this.

I can feel that the gas commin out from the compressor that goes to the condenser is varm. The metal lines coming out of the evaporator is quite cold. Temp of air in car drops maybe 10 degrees or less when its 70 F outside.

[Cusser]

You need to find a shop that services R-12 refrigerant; they would have equipment to pull out the remaining R-12 and weigh it, to determine how low your charge is.

From your pressure readings and that your high side line is only warm and not hot, plus your pressures (if measured at about 2000 rpm) indicates you have lost refrigerant over time.

[Gustav4523]

You need to find a shop that services R-12 refrigerant; they would have equipment to pull out the remaining R-12 and weigh it, to determine how low your charge is.

From your pressure readings and that your high side line is only warm and not hot, plus your pressures (if measured at about 2000 rpm) indicates you have lost refrigerant over time.

Thanks

Whats the differende between a low charge and a bad compressor. I try to undestand the problams. Its not easy to find a shop where I live that can service old systems. They need instruktions.

[JohnHere]

Does your car still have R-12 and a Sight Glass on top of the Receiver Dryer? If so, and you have on hand or can still purchase R-12 refrigerant, you can do it yourself the simple, old-fashioned way without a shop's intervention, presuming you have a Manifold Gauge Set (MGS) with the proper fittings and a tapper valve that pierces R-12 cans.

Chances are, the system is low on refrigerant, as Cusser suggested. Check the Sight Glass while the system is running at about 1,800 engine RPM. If you see bubbles or just streaks of oil, then the system is definitely low.

Add refrigerant (be sure to purge all the MGS lines of air) until the bubbles just disappear. It might take two or three cans to recharge the system properly depending on how low it is.

You should now have nice cold air again with good pressures. If not, then the system has deeper issues that will require additional diagnosis and leak testing.

[Gustav4523]

Does your car still have R-12 and a Sight Glass on top of the Receiver Dryer? If so, and you have on hand or can still purchase R-12 refrigerant, you can do it yourself the simple, old-fashioned way without a shop's intervention, presuming you have a Manifold Gauge Set (MGS) with the proper fittings and a tapper valve that pierces R-12 cans.

Chances are, the system is low on refrigerant, as Cusser suggested. Check the Sight Glass while the system is running at about 1,800 engine RPM. If you see bubbles or just streaks of oil, then the system is definitely low.

Add refrigerant (be sure to purge all the MGS lines of air) until the bubbles just disappear. It might take two or three cans to recharge the system properly depending on how low it is.

You should now have nice cold air again with good pressures. If not, then the system has deeper issues that will require additional diagnosis and leak testing.

Thanks!

R12 is not legal in my country so I cant búy it.

I did check pressure in system this morning with engine on. It was 72 F and system pressure around 73-74. That indicates that I have enough refrigerant. Someting else must be wrong. Coluld it be a bad compressor or an expansion valve? I dont know how to figure out what it is.

[Gustav4523]

Does your car still have R-12 and a Sight Glass on top of the Receiver Dryer? If so, and you have on hand or can still purchase R-12 refrigerant, you can do it yourself the simple, old-fashioned way without a shop's intervention, presuming you have a Manifold Gauge Set (MGS) with the proper fittings and a tapper valve that pierces R-12 cans.

Chances are, the system is low on refrigerant, as Cusser suggested. Check the Sight Glass while the system is running at about 1,800 engine RPM. If you see bubbles or just streaks of oil, then the system is definitely low.

Add refrigerant (be sure to purge all the MGS lines of air) until the bubbles just disappear. It might take two or three cans to recharge the system properly depending on how low it is.

You should now have nice cold air again with good pressures. If not, then the system has deeper issues that will require additional diagnosis and leak testing.

Thanks!

R12 is not legal in my country so I cant búy it.

I did check pressure in system this morning with engine on. It was 72 F and system pressure around 73-74. That indicates that I have enough refrigerant. Someting else must be wrong. Coluld it be a bad compressor or an expansion valve? I dont know how to figure out what it is.