I live in an area (deep south Texas) that's just hot and humid, ac is a must. 

 

My ac use to blow 45 degree or colder air no matter the temperature humidity outside, recently the ac performance began to degrade. As the ambient temperature increases so does the temperature of the air coming out of the ac. On a day in the 90's temperature of the air coming out of the center vent (temp readings done with max ac, fan on high, center duct) would run from 55-65 and humid air.

 

The ac system is still all original parts from 2002, other than being recharged 2 years ago at the dodge dealer and few weeks ago.

 

After putting gauges on here is the basic findings (center vent temp is about 55-65): 

 

Static pressure is same both sides (100 psi)

 

At idle Low Side 40-55, High Side: 200-350 (ambient Temp, 84-95). The high side does show “spikes”  occasionally, sometimes they are rapid spikes meaning a jump on high side of 50-100+ (low side stays the same as I recall, might go up a bit), then high side drops to previous psi reading, sometimes the high side will start say at 200, then gradually go up does not come down, low side will go up as well, not sure if that means anything ?

 

At 1500-2000 rpm Low side 35-40, high side 200-250 (both sides steady pressure, no spikes etc.)

 

Other findings:

 

The condenser seems to have a the same temperature (running my hand across condenser), anywhere I place my hand. Dryer / Accumulator seems to have good sweating, high side to me should feel “hotter”.

 

When using the gauges I recover some r134a, in the sight glass the color was reddish / brown, is this normal ?

 

Once in awhile (mainly when ambient temperature is 95+) when the ac compressor first starts, you can hear it strain , the belt does slip a bit on the compressor pulley when this happens. Overcharged system ? I evacuated enough freon to start short cycling (thinking overcharged), then added back 1 120z can. This seems to have stopped the “hard start” as I call it, seems to cool just a tad better. Can't test for a hot day as cold front came threw last night.

 

Could I have a blockage (orifice or dryer/accumulator), evaporator plugged with years of dirt, ac flush needed, to much ac oil ??

 

Thanks for any help 

You do not want to allow liquid refrigerant to get to the compressor unless you want to replace the compressor. Vapor is the correct way to do it.

  On 12/19/2014 at 4:22 PM, MnTom said:

You do not want to allow liquid refrigerant to get to the compressor unless you want to replace the compressor. Vapor is the correct way to do it.

 

Some poor soul found out on a VW...

 

 

 

My suggestion was going to be more airflow through radiator and condenser, I had an rx7 once and after body kit my ac didn't work worth of crap, only at hwy speed it would be ok. Took it to ac shop and guy put a big as. Fan in front of car and ac worked perfect. Never did cut any holes in new bumper, but that was the problem, restricted air flow.