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Can't get lower then 52 degrees

trackman on Fri October 01, 2010 9:07 PM User is offline

Year: 1979
Make: lincoln
Model: continental
Engine Size: 400
Refrigerant Type: r12
Ambient Temp: 75
Pressure Low: 33
Pressure High: 150
Country of Origin: United States

Flushed system replaced expansion valve, drier and new compressor. Added oil 6oz compressor, 2oz condensor, 2oz evaporator and 1oz to drier. Evacuated system for one hour and charged with correct amount r12, 68oz. At 1500 rpm, 75 degree outside air LOW reading 33psi HIGH 150, blower on medium speed center register reads 60 degrees. At highway speeds can't get any lower then 50 degrees. Shop manual says readings at 75 degrees and 0 feet sea level readings should be 28-30 LOW and 130-160 HIGH and center register should read 40-45 degrees. My readings seem fine except for low side but i don't believe 3psi makes much of a difference. I thought maybe i overcharged so i released some freon and noticed a lot of oil come out with the freon. Do you think there could be to much oil in system which might be reducing cooling or any information would be appreciated.

Chick on Sat October 02, 2010 8:01 PM User is offlineView users profile

Are you sure you clamped the expansion valve tube tightly on the suction tube and covered it with insulated tape? does this car have a POA or STV in the line, does it have a sight glass anywhere in the system??

Email: Chick


Freedoms just another word for nothing left to lose

chris142 on Sat October 02, 2010 10:40 PM User is offline

How about a blend door stuck or not sealing? Vacuum leak? Those cars had miles of vacuum hoses.

trackman on Sun October 03, 2010 10:14 AM User is offline

Yes the expansion valve tube is clamped tightly and insulated. The system has a POA valve and there is no sight glass.

trackman on Sun October 03, 2010 10:18 AM User is offline

I'm going to check the blend door and vacuum hoses for leaks. Thanks for that good info.

newton5 on Sun October 03, 2010 11:35 AM User is offlineView users profile

That system uses an A6 compressor, which has an oil sump much like a small engine.
If you didn't drain the oil from the compressor and then added the specified amount to the other components you now have way too much oil in the system.
That could certainly be the cause of your problem.

It's an easy mistake to make if you are only familiar with newer systems. Most modern compressors don't have a sump and all of the oil circulates with the refrigerant. The A6 is an older design. Most of the oil stays in the sump and only a small amount is carried through the system.

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