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2011 Acura RDX. i vaccumed and added freon a while ago (about a yr ago as the AC wasn't working properly.) Turned out that the mode actuators were stuck or not working. so ended replacing all those. It worked fine till now. the problem started off with AC not working intermittently. for most part it used to work and sometimes it used to blow hot. Thought it was the relay going bad. so changed that. Now the reverse is happening, AC works for sometime (around 10min to sometimes upto an hr) and then the clutch disengages and never engages again. literally had to wait for the whole system(car) to cool down before starting the car again for the ac to work. the low side pressure stays around 30 and high side remains around 100 all the time when the AC is working. the low side stays around 30 when the AC is working and then works its way up to around 100 once the clutch disengages. Teh ambient temperature when i tested were 85 to 95+. I am is Dallas, TX Once the clutch disengages the pressure seems like getting equalized to the high side like it wsa static pressure.

I did add the dye/oil when adding freon so that i can check the leaks. i don't see any sign of leaks on the condenser/top of compressor or around the lines. obviously i can't see inside the evaporator without pulling it out, so can't tell. but the lines going into and out of the dash seem to be ok without any leaks.

Is this a failing compressor or something else going on. should i just vaccum and recharge it? if the freon is low then i know the compressor engages too often. not sure if its overcharged either.

Srinivas Pulukuru
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Refrigerant capacity is always labeled on the engine hood or chassis. Under most situations, overcharging will be displayed as higher low and high side pressures. This presumes you have a temperature/pressure chart reference from service manuals. Some manufacturers require above idle rpm for pressure checks since pressures vary with rpm, outside temperature and humidity.

When ac runs then turned off, pressure gauges always display low side pressures rising as you observed. Pressures equalize as the thermal expansion valve is bleeding off high pressures into the evaporator coil, resulting in low side pressures rising. Normal after the compressor is shut off.

When ac is turned on, cooling fan(s) are automatically turned on with some having several speeds as outside temps, cooling system temps rise and ac pressures vary, requiring stronger airflow thru the condenser coil and radiator. Do you see/hear your cooling fans running and change speeds as outside temps and cooling system temps rise? When a cooling fan fails or runs slower, less airflow cools condenser coil and radiator, raising ac pressures until a sensor detects excessive high pressures to trigger disabling the compressor until high side pressures drop.

Normal r134a pressures should be; 29-39 psi low side, 125-250 psi high side. Less than correct refrigerant may trigger the pressure sensor to disable compressor operation. Lubricating oil relies on refrigerant to circulate it, returning to lube the compressor. Less or low refrigerant means less or zero oil return resulting in compressor self destruction. While it's not rocket science, vehicle refrigeration is not diy friendly. Consider ac systems as complicated as super or turbo charging systems.

It wouldn't be unusual for cooling fans to wear out after 13 years of heavy ac use in Texas hot/humid weather.

F Dryer
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