A/C refrigerant leak

First some cautions. The system on the Prius uses a totally different lube from other automotive system. Absolutely no PAG oil!!!!

Don't use equipment that's been used on conventional automotive A/C. It's contaminated and using it can cause a whole world of hurt. It's a standard R134a fitting. This is the tool I bought specifically for my Prius 1. A/C Pro C Pro / Recharge hose and gauge - Not for Hybrid vehicles with electrical driven compressors ACP-400- ReadReviews onA/C Pro #ACP-400

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Note that it has a gauge, a trigger, and an easy to use R134a low side connector. The trigger seems to hold pressure, I've had a pressurized can of pure R134a connected for about 3 weeks One can of R134a will fill the Prius 1 system, you want to use the plain refrigerant, no sealers, dyes, or oil charge. I guess I'd take the car to a standard A/C shop, fill it with your recharge equipment and let them use a freon sniffer to find your leak(s), but don't let them replace any o-rings, they'll want to lube them with PAG oil. I keep my new filler in a ziplok bag when not using it. You can get a pretty good freon and halogen detector from Harbor Freight for $69 minus 20%--a nice tool to have. Electronic Freon and Halogen Leak Detector

Best, tho, to take it to a hybrid shop, either Toyota or an independent.

With the engine running and the A/C on and set to its coldest, give the system short shots of R134a. You don't want to over charge, so anything over about 36 psi at the low side connector is not advised. Trying to find the leaks with soapy water might work, but doing it with a sniffer is a better solution. If you replace parts, you'll need to pull a vacuum, and I think the best thing is to let a Hybrid trained tech do this work.

Hope this helps.

 

This is a thread about the Gen 1 A/C system, in the Gen 1 forum, so that doesn't apply. The high-voltage electric A/C systems requiring ND-11 oil started with Gen 2.

The conventional, mechanical compressor in Gen 1 uses ND-8 oil "or equivalent" (see page AC-49), which seems often equated to PAG-46 (I'd be more sure I found an actual Denso page that says so, and I haven't, but vendors seem to agree about it).

And yes, if you have a Gen 2 or later Prius requiring ND-11 oil, then be sure to use only that. But this thread's about Gen 1....

-Chap

 

Thank Chap for the clarification.

Primuspaul, I don't think I'd be using compressed air to diagnose a leak. Would not be a good thing to inject moisture and contaminants into a closed system, plus the high and low side shrader valves aren't even close to the size of a tire valve. And low pressurization of the system, say about 10 psi wouldn't cost much and you probably could get any neighborhood garage to sniff the system for leaks--probably charging nothing.