A/C Troubles - '08 w/ 60F Vent Temps @ Max A/C

Hello all.

It's been a while since I've posted, but I'm always lurking.

Recently, the A/C on my '08 Prius started blowing cool instead of ice cold with the A/C on its max setting. Before anyone wonders if I did a search of this forum, yes, I did.


A month ago (May 5), I took the Prius to a reputable independent shop in my local area. After having read the forums after I kept having difficulties, I wish I hadn't. They noted the refrigerant was low and topped it up using R-134a. They noted it held a vacuum, so I didn't believe it to be leaking at the time. However, after A/C performance didn't improve, I took a closer look at the service order. They used Frigi-quiet universal A/C oil (what I now understand is basically a death sentence for the entire system). Its technical data sheet notes it isn't recommended for use in hybrid-electric A/C systems. The reasons why no other oil besides ND 11 oil should be used are explained in many other threads (so others who may read this thread and need help, do a bit of searching).

While I understand the damage is likely already done to my A/C system (despite no DTCs manifesting... yet), I marched back to the shop and showed them their service order and the data sheet. They evacuated, flushed, and refilled the system with R-134a and something they noted as "AC hybrid lube" on the service order. However, the fluid visible through the sight glass is still green instead of the clear it should be. I'm considering taking it to a dealer, but they offer no loaner vehicles and likely can't do much of anything to save the A/C system at this point.

However, the system still works for now and performance is still unchanged. While driving back from the shop, a 90 degree day with about 70% humidity, the temperature at the vents (measured with a dial thermometer) only got down to 60 degrees F. I've got considerable battery drain since this ordeal started, and MPG is down to 42.8 (from its usual 47 - 48). I understand that without measuring pressures on the low and high sides, there's only so much diagnosing that can be done behind a computer screen. However, in a thread I searched, Patrick Wong measured his vent temps at 25 F on a 100 F day. Something is definitely wrong with my Prius.

All fans are operational and cycle properly, and the cabin air filter is brand new. The car has never been in an accident. However I can't positively confirm there isn't a tiny leak somewhere. I do a lot of highway driving, so I'm unsure of the condition of the fins on the condenser.

With recent cooler weather where A/C isn't needed as badly, I've had the MPG average up to 51.9, so I believe the battery is at least still somewhat healthy. The car currently has 203k miles, and I live in south eastern VA. Any help would be greatly appreciated.