'94 Lexus ES300 - A/C fades



I have a 1994 Lexus ES300 with 150k miles. Over the past couple of years, I have had an intermittent problem with the air conditioning that is becoming less intermittent.

Usually, upon starting the engine, the A/C will blow cold out of driver and passenger vents as expected. Over a matter of minutes, the vents will slowly begin to warm from driver to passenger, until they are blowing warm. Upon stopping and restarting the car, the vents will continue warm. Sometimes, the A/C will blow warm upon starting the first time.

For example, I was driving from Albuquerque to Arizona today. The A/C ran great for 40-minutes, then began to fade.

The last check showed the A/C working fine with coolent pressure normal, etc.

I can provide more information if I’ve left anything out.