Part 2. How to properly charge an auto AC R134a refrigerant air conditioning system.

Part 2 of "How to properly charge up an auto R134a AC system" using pressure gauge and off the shelf 12 ounce R134a refrigerant.
Note about charging Liquid (can upside down) versus Vapor (can right side up):

The freon can should be upright so that refrigerant "vapor" is drawn into the low side. Remember that the Low side, also known as the suction side, normally operates as a "Low Pressure Vapor" state that is drawn directly into the compressor. You don't want to "slug" the compressor by inverting the can and adding freon in the liquid state. A caveat to the above statement is that sometimes it may be necessary to invert the FIRST can(initial charge) for a few seconds at a time to "prime" the system with freon so that the compressor will engage. But you should never charge an AC system with pure liquid refrigerant. The compressors job is to "compress" refrigerant vapor coming from the Low side. The compressor is not designed to compress liquid and can be damaged if too much liquid is put into the low side.

Category:

Autos & Vehicles

Tags:

• R134a
• AC
• auto
• charge
• recharge
• refrigerant
• R12
• evacuate
• evacuation
• charging

[hotroddfalcon]

Start listening to the instructions at 0:21. And turn your can upside down and shake~~~~

[mikecarter79]

@hotroddfalcon yes, this is another good method of getting as FREON as possable out of the can and into your system.  Brave....thank you

[mikecarter79]

@mikecarter79 Brave=Bravo !!

[texasthojp]

Hi Mike,

I need to pick your brain. I'm working on a 99 ranger with an aftermarket AC. It has a Sanden 508 style compressor with universal condensor, evaporator, condenser, H style expansion valve, and so on. I have fixed the leaks it has, replaced the rubber hoses, o-rings, pulled a 29 mm/hg of vacuum and recharged the system to 24 ounces. It cools, but no where near as well as it should. At 100F ambient, the low side is at 47 psi and high side 260 psi. Do I need one more lb of R-134? Thanks..

[mikecarter79]

@texasthojp Since you are dealing with an aftermarket AC system, I will give you my opinion, but please make your own decision. I think you are correct, and that you should add an additional 1/2 to full can. You have a high ambient of 100F, and I will assume 50% humidity. At these conditions, you should have approx. 43psi Low side and 360psi on High side. The 260psi you are reading is too low for 100F ambient. These numbers will flucuate some when fan turns on, expansion valve adjusts, etc.

[mikecarter79]

@mikecarter79 The 43/360 Low/High psi should be measured with the engine running(idle) at 2000 rpm. If you can achieve numbers like this with the addition of more R134a, your center air duct temp should be around 73 deg F. Doesn't sound cold, but these are the numbers you should be getting when your outside ambient is a whopping 100F !! If your humidity is higher than 50%, your Low/High psi's will increase slightly and center air duct temp will be a few degrees higher than 73F.

[sickst33l]

Isn't that a valve at the manifold for yellow line so you can purge????

[gibhvac]

Are you sure it's ok to leave the suction side open when you are purging the air from the yellow hose that would be in the yellow hose between switching cans. It seems to me the suction line being open or on would pull outside air into the system when doing so. The correct way for charging method on a residential AC system. Is to purge the yellow charging hose with both low and high sides closed, slightly loosen hose at manifold until vapor is present from the hose, tighten hose, and from there

[00Kaporal]

I wanted to ask if anyone knows, what would make your auto ac alum hose freeze up?

[00Kaporal]

Mikecarter79

I'm new here & I'm hoping to help me out.

I have a 2001 dodge durango, 4x4 5.9l, I was told to change the exp. value.

I hooked up the manifold gauge after 5min the low reads 50psi high at 420psi

at 2000rpm low at 35 & high at 375, temp at vent 66d outside temp 95d.

with this info. does it tell you if any other part needs to be replaced?

thanks for your help..

[vaINZANE]

thank you.

[txpkrdad]

@83Hotgears

First thing in your situation i would do is jump wire the low pressure cutoff switch...You can do a google search for how to do this and this will tell you if you compressor clutch is not engaging because of a faulty switch,low on coolant or if the clutch is bad on the ac compressor itself.

[jumar1281]

if you never turn on the high pressure side, why does it even need to be connected? i am about to do this in my car, and only planning to buy the oil, 2 cans of freon and the hose that will connect it to the low pressure side. this should be sufficient right? or do i need to buy this whole setup you're using?

[BiteDoctor]

your vid cleared up a few doubts i had. thnx for posting!

[83Hotgears]

Mike, thx for the video.very useful info. I do have a question for you on my 97 grand prix gtp. I have been looking into fixing my ac but not sure what or where to start to fix it. The only thing I can think of is... The clutch on my compressor is not engaging. Maybe the compressor is no good, or it be that it will not turn on cause of having low pressure in the system? Or should I just charge it and see if the clutch will engage to fix. L