Ac not cold at idle or around town

[Dustin Gebhardt]

If the AC works fine while moving, but struggles while idling, then I would say that the condenser is struggling. The AC on my '07 make's 70'F air (center vent, driver's side) when idling in >90'F ambient weather or makes 50-60'F air while driving in town. But when I'm driving for several miles, the AC temperature drops below 30'F. I figure that the condenser cannot shed enough heat when the car isn't moving. I plan on adding a push e-fan in front of the condenser and transmission coolers to help with this issue.

I should also mention that I added a resistor across the temperature sensor for the evaporator/blower (located behind the glove box). I don't recall the exact value, but I think it is around 300K ohm. This causes the system to think that the evaporator temperature is higher and runs the compressor longer. I did this because my compressor was cycling on/off when the sensor was reading in the 50's and 60's (center vent temperature). Now the center vent will get down in the high 20's on a mild day when driving on the freeway. It occasionally will ice up, so I think I need to change the resistor to something higher (maybe 330k ohm or 360k ohm). This takes all of 5 minutes on my '07, but YMMV.

 

[Motorcity muscle]

I would have the system reclaimed and note the amount of oil removed. Then recharge to factory specs including the oil amount and take pressure readings again.

Your pressures are higher than what we normally shoot for. We usually teach the students to run the low side pressure just above 32 (freezing) at high idle. Low side pressure will be very close to evap air temp when running.

I'm running my low side at 35, high is around 225.

Air flow through the condenser will effect both high & low pressures. Lower air flow equals higher readings.

I concur, system overcharged.