Question I have a 67 Ford Mustang (289 V-8, 4 Barrel) that originally came with factory
A/C. The previous owner replaced the compressor (and possibly other
components) with a Sanden unit. The system is still running R12. My
problem is that the air coming out of the registers takes a long time to cool
down and never seems to get cold enough especially on days when the
temperature exceeds 80 degrees. Also, the temperature gauge shows that
the engine is approaching an overheating situation when the A/C system has
been on for a few minutes, though it never actually overheats. Visual
inspection indicates that the compressor is working (i.e. the low side and
high side fittings are cold and hot respectively). Pressure readings for the
A/C system prior to engaging the compressor are 80-85 lbs (both high and
low sides) on a 75 degree day and 95 to 105 lbs on warmer days. With the
A/C system on high, and idling at 1500 RPM, the low and high sides read 25-
30 lbs and 190-210 lbs respectively. A couple of other things that I have
noticed is that the condensation hose leading from the evaporator is very
warm to the touch and Condensation does come out of the hose when the
system is operational. Sometimes when I turn on the system, I notice a
rattling under the hood. The rattling noise sounds like the fan is hitting
something, but I can see no evidence of any damage and the compressor is
firmly/correctly mounted.
Any thoughts or suggestions that would solve my problem would be much
appreciated.
Answer first put the car where you can put a mist of water on condenser with running and guages connected if pressures drop a lot with a mist of water sprayed on condenser then you may not be cooling freon enough causese can be overheating because low on coolant-poor airflow (is fan shroud still on radiator)-dirty condenser and or radiator-clogged radiator-if all this is good then evac a/c system evacuated and recharged with exact amount of freon then see what your readings are-you could have expansion valve problems or dirty evaporator but readings are not leading to that.
