Recharging '08 Prius A/C system

http://priuschat.com/forums/knowledge-base-articles-discussion/50679-c-oil-replacement.html

Doesn't address all your questions, but helps with #2, 3 and 4.

You might try a PM to Jelloslug or others in that thread.

 

Just wondering, your 08 is still under Warranty so why not let the dealer pro does the AC work?

 

Maybe he's dealing with a salvaged car or he's replacing a part such as a condenser that suffered from FOD.

AC work is HIGHLY, HIGHLY and did I say HIGHLY dangerous due to the fact that refrigerant can cause severe frostbite if mishandled and a careless mistake such as connecting a can of refrigerant to the high/suction side of the system or not knowing how to properly use a manifold gauge set/vacuum pump/recovery equipment can have dire consequences. If you really want to learn how to service automotive HVAC, I suggest taking a class at the local community college as there is also an enviromental element you must also know a well.

The Prius HVAC system is similar to home/commercial HVAC systems in which it uses a hermetically-sealed compressor - meaning the electric motor is housed along with the compressor mechanism. This means special POE(NOT PAG or off the shelf POE) oil such as ND-Oil 11 is used, anything else creates a short in the motor windings. Otherwise besides the fact the Prius HVAC uses a different type of compressor, it is serviced like any other car HVAC system. You can use the same compressor lubricant or Nylog to lube the O-rings - but be careful when you add oil to the system, you don't want to slug the compressor with oil.

 

I just went through this myself as I had to replace a damaged condenser in my 07 Prius. One definitely needs a good understanding of repairing A/C systems in general and specific information that applies to hybrid vehicles. Here is some info that I gathered specific to the Prius:
1. The Gen 2's refrigerant capacity is right at 1 pound (15.9 +/- .1 oz.)
2. The system oil capacity is 4.5 oz (ND-11 oil).

If you remove a component always measure how much oil you take out so you know how much to replace
(however, never put the old oil back in).
The oil is very thin and easily flows for measuring.

If per chance the oil was lost (due to damage, etc.), then the system must be flushed per Toyota's instructions and new oil measured in. If the compressor failed you would also want to flush the system and replace other recommended parts in the system. The Prius compressor is a scroll type and can exert many fine metal particles through out the system if it fails bad enough.

The ND-11 oil is available either in refrigerant pressurized cans or by bulk (non-pressurized) depending on how you want to add it to the system.

Amazon sells it in 3 oz cans with 1 oz of R134A. Just search for
R-134a Hybrid Vehicle A/C Compressor Oil

Again, there is much knowledge and equipment that needs to be obtained before starting a project like this and many variables that affect what decisions you need to make. However given enough determination it can be done.