A/C system has no refridgerant

Hi everyone,

So my sister-in-law (17 year old) was gifted a 2007 Prius from a family member with non-functioning A/C. She's doing my wife and I a favor via some babysitting so I told her I'd look into her non-functioning A/C and see what I thought.
To be fore-warned, I'm a Jeep guy that prefers 2 solid axles and a manual transmission with my manual windows, so while I have quite a bit of experience turning a wrench, I have zero experience with hybrid vehicles.

Immediately I checked for the most obvious issue, evidently a concern to all vehicles regardless of hybridocity -- whether or not it had any refrigerant. It did not.
(I checked this by blip-ing the low pressure service port and when I heard no escaping gas sound I pushed the schrader valve down and it was fully, totally empty.

So there's a leak somewhere in the system.

Researching briefly on the subject, it appears that 2 prime suspects for leakage on these cars are:
1) Rocks kicking up and busting the condenser
and
2) A hose that likes to rust/rot near the front frame

I'd assume that o-rings drying out and moisture causing holes in the evaporator are also possibilities as well.

I also learned that unfortunately, I can't even use my manifold gauges on her vehicle since I've used them on a conventional vehicle system that uses PAG oil and that even more unfortunate, it seems you have to pull the entire dash apart to get at the majority of the system components.

I'm contemplating getting a cheapo hose and running a charge of refrigerant in and seeing if I can detect a leak in either of the suspect areas.

Questions:
1 ) Any advice or thoughts from those that are more experienced with these vehicles and their A/C systems?
2 ) Would I be safe to pull a vacuum with a NEW set of manifold gauges using the vacuum pump that I've used on my conventional system?

 

Awesome - thanks Patrick!

Is the only receiver/dryer / accumulator (the part normally replaced whenever the system is opened to the environment) the "cooler dryer" on the side of the condenser?

So is it accurate that one cannot access the evaporator o-rings without pulling the dash apart?

If I did need to/want to pull her dash apart to get to the evaporator area, how difficult is this in reality? I have the Factory Service Manual sub-section on A/C from another post on this forum and it looks lengthy, but not complex (as opposed to say, re-gearing a differential with the torque measurements, shimming, etc). Of course, the videos and instructions always look easy...

 

Just to follow up on this.

I attempted to charge her A/C and use my refrigerant sniffer and was unsuccessful.

Fortunately though, she did get cold air for a short time, so I know at least that the compressor is compressing, and the various parts are all functional and not plugged up.

I then attempted to use a hybrid-safe dye and discovered that there is a hole in her condenser, on the driver's side lower part. Fortunately there did not appear to be any other sources of leaking (and I had a good view of the compressor, lines, etc.)

I've got a new condenser and some ND11 oil ordered and on the way. I'm going to pick up a 2nd set of manifold gauges (to be dedicated "hybrid" use only) and will swap her condenser out and pull a vacuum on the system and see if her system holds it.

I'll update with the results when I complete the next steps.