Air Conditioning problems - dealer only?

You can use any R-134A that doesn't contain compressor oil as far as I know. You also need a separate hose/connections for the recharge that have never had oily R-134A in them or else you may contaminate the Prius system. Most auto shops have the special refrigerant, but it is definitely the exception not the normal can.

So it is a "special" coolant with no lube in it which is what makes it special.

FYI: This is not my Prius area of expertise. I believe I read that information from one of Patrick Wong's old posts. I would do more research or wait for others to chime in before making a full decision.

 

No you do not have to go to a dealer. 1: Yes there is a special oil 99% of shop will not carry in stock and most do not even know about, ( DENSO ND-11 ) A 8oz metal can of DENSO ND-11 about $170 to $230 and once you open the sealed can and some one dose not tighten or put back the cap right-away the oil goes bad, it wicks out water ( moisture ) out of the air about as fast as if you dip a small corner of a sponge in water and the water flows up to the top of the sponge.
2: If you do try or have some one try, only use R134a refrigerant with nothing added in it.
3: I would recommend going to my photo album it is only about air conditioning mostly about Prius burned up compressor and leaks.
4: Most problems arise from a owner of a car not keeping the refrigerant full at all times, ( waiting too long after they notice their a/c is getting warmer.)
5: THE #1 cause of burned up Pruis compressors is Body Shops serviced the air conditioning after a front end collision. Body shops are the lest TECH qualified to work on anything that is not dents and paint. Most body shops come from the lowest end of the gene pool, not all but most.
6: The #2 cause of burned up Prius compressors I receive to fix comes from Automotive repair shops, they just do not want to invest in the new and proper tools and equipment dedicated just for Hybrids and electric cars
7: The 3rd cause of burned up Prius compressors comes from the DIY who got bad information, and just keep topping off the refrigerant in the car.

If you don't want the dealer then I highly recommend a Hybrid only shop if you have one in your city. We here in San Francisco are vary lucky to have Luscious Garage. For experience with Hybrids no old school shop around here evens comes close to Luscious Garage.
A shops A/C recharge rate are some were around $180. to $250+ depending on were you are in a big city, they should add dye and yes the proper way is to look for the leak first with a electronic refrigerant leak detector, then recover all the remaining refrigerant out of the system, then vacuum the a/c system down to 700 or 500 MICRONS or less, then its time to recharge by weight only! not guess work!. Not all leaks can be found the first time so you may have to return later so they can find the leak. The leak may get bigger and leak constantly so it can be found with a electronic leak detector or the UV trace dye is not showing so when the shop uses their UV light it will glow brightly at the leak point.
The most common leak on a Pruis is the condenser. You can see photos in my photo page album of what common leaks look like on your Prius.

PS. when was the last time you replaced your cabin air filter located behind your glove box?
Good luck
Tom Lech, Lech Auto Air Conditioning