Automotive Air Conditioning Information Forum

Hi everyone,

I have a 1997 Chrysler Sebring LX Coupe 2.5L V6 with 105k miles. The engine is Mitsubishi and the transmission is Chrysler, everything else is almost identical to a 1997 Mitsubishi Eclipse. 4 years ago, at ~94k miles, I replaced the a/c compressor, condenser, receiver/drier, expansion valve, and evaporator: all new parts. I evacuated the system and waited the requisite time to ensure a vacuum was retained, and added the exact grams of 134a refrigerant as per Chrysler shop manual specifications. The high and low side pressures at ambient temperatures were very close to correct as per shop manual specs. Interior discharge air-vent temp was ~45 degrees in Miami 95 F -degree summer.

I just started using the car again after it sat for the past 18 months and the a/c barely cooled. I tested the system pressures as per shop manual at 98 degrees in the shade. Low side tested at ~80psi at 2k rpm with high side at 110psi. At ~4k rpm the low side dropped to ~45psi and the high-side remained at 110psi. Shop manual list pressures at 95 F degrees ambient temp at 30psi low-side and 206psi high-side at 1k rpm. Lines going into and coming from the condenser registered at ~115 degrees using a Klein Tool infrared thermometer as did the lines from and to the evaporator. Any help would be greatly appreciated.

Thanks!

I'd evacuate and weigh the amount of refrigerant, and then add proper amount with a little UV dye, and check/repair leaks. And make sure all the condenser/radiator fans are operating properly (electric or fan clutch, don't know this vehicle).

The electric condenser and radiator fans are both working, and the compressor clutch is engaging.

Evacuating the system and adding some dye and recharging it sounds like a good diagnostic starting place and only will cost about $30. I am certainly no expert, but what is perplexing to me is that the compressor is pulling the low side down from ~100psi at idle to ~45psi at 4k rpm, but the high side stays constant at 110psi regardless of the rpm. I was hoping that some experienced pro might be able to tell me that means the compressor is shot, or the drier needs replacement, or the expansion valve is stuck, or something else clearly needs fixing.

The assumption when evacuating/recharging and adding some dye, is that there is a leak, and the lack of cooling is a result of a low charge. Are these high/low side readings I am getting typical of a low charge?

It's hard to tell what's wrong unless the existing refrigerant is recovered and measured (weighed), the system thoroughly evacuated, and the exact amount of refrigerant weighed back in as previously mentioned. If you still have problems afterwards, at least you know the charge is correct and can go on to other potential problems.

Thank you. I'll do that and also add some dye as Cusser suggested.

‘I evacuated the system and waited the requisite time to ensure a vacuum was retained.’

This statement is a bit elusive. We would prefer that you vacuumed for at least 1 hr, and if you had a vac gauge, what that reading was.
With windows open, 1800 rpm, set to max cool and max fan , obtain lo and hi pressures.

Yes a leak is likely