Quote:
Originally Posted by redpoint5
The AC is a closed system and not subject to external pressure differences. Are you saying the high side pressure would rise due to a rise in condenser temperature?
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Yup, high condenser temps cause high system pressures system-wide. Actually low side pressure and evaporator temp track each other linearly, with the old R-12 stuff it was straight over psi to degrees Fahrenheit, so 34psi would make for a 34 degree evaporator, 40 to 40 etc... Poor airflow, like a inoperative cooling fan or somesuch is a common cause of high system pressure and poor cooling.
As I said before if there's insufficient airflow through the condenser the A/C won't blow cold so you'll know it if it's a problem. The condenser has to shed all that heat it picked up in the evaporator somehow, the refrigerant can only carry so much heat.
And redpoint, your fan should not blow enormous amounts of air all the time. It's normal for it to blow a lot of air around for a little while after you turn it on, even cold, but it should loosen up until the motor gets good and hot. Get a new clutch on that baby, its worth some FE and the peace and quiet.
JeffD, I've been swinging wrenches for 10 years and I've never seen a temp rating for a fan clutch. If it runs all the time it's locked up, if it doesn't get stiff and move air when the engine's good and hot it's stuck loose. They're usually inexpensive enough that more scientific diagnostics are not cost effective.