How to: Recharging your A/C - A-Z

[ma96782]

Q: When you evacuate the gas (R-134a) out of the system..........does it take the oil (PAG-100) out too?? So, do you have to replace the oil??

Aloha, Mark

 

[Glacier991]

The answer is "Depends". If your system had a real slow leak and eventually lost all your refrigerant charge, the odds are high you have virtually ALL the oil still in the system. On the other hand, if you blow a hose and has a near explosive loss of refrigerant the odds are you will have lost a significant portion of the oil along with the refrigerant.

When I run my recovery machine on a charged system, (My recovery machine separates oil), I often get 2 to 4 oz of oil out of the system, which I then add back in prior to recharge.

 

[ma96782]

Thanks for the answer.........I had thought, that the evacuation/vacuum was taking, "everything out."

So, in the end, the shop using the right tools, will measure and replace the proper amount of oil. And, the refrigerant gets replaced based on the factory spec. X amount of oz. (also taking into account gauge readings and temps).

Whereas:

Shade tree guy w/ a slow leak shouldn't be overly concerned about oil loss.

And,

The shade tree guy doing an evacuation/vacuum w/o a proper recovery machine (that separates the oil and gas) will just have to wing it (as to replacement of oil). And, he will usually replace refrigerant based on gauge readings and temps (as he doesn't have an expensive scale).

Aloha, Mark

 

[Glacier991]

you pretty much hit the nail on the head there.

 

[PDA1]

Where to put oil?

Where is the oil PAG 46 (I think) put into the system on a 96 Explorer?

NAPA says 7 oz go in.

I know I put some in the compressor....but where does the rest of it go?

Do I put any into the accumulator? If so, which pipe on it does it go in?

 

[ma96782]

PDA1,

*Rule of thumb........(taken from the Haynes Book)

If no major oil loss has occured, and if only a single component must be replaced, oil can be added to the system by putting it into a specific component. Use the amounts shown below:

Condenser - 1 oz.
Receiver Drier - 1 oz.
Desiccant bag in VIR - 1 oz. plus the amount drained from the receiver-drier.
Evaporator - 3 oz.
Accumulator
a) Ford - 1 oz. plus the amount measured
b) General Motors
1) DA-6 - 3 oz. plus the amount measured
2) A-6, R-4, or V5 - 2 oz. plus the amount measured

It's important to note that, since oil distributes itself throughout the system during operation, it isn't absolutely necessary to add the oil to the compnent being replaced. With one notable exception, as long as the amount of oil lost during the replacement procedure is added somewhere, the sytem will be fine. The exception? If the compressor is being replaced, always put the oil into the compressorand not somewhere else.

Example:

I remove the old accumulator (my '94 Ford Explorer). Then, I drill a hole in the bottom of the accumulator and drain and measure the old oil.

Say that it's 2 oz. of old oil.

So, prior to installation of the new accumulator, through one of the pipes of the accumulator I'll add the new oil.........2 oz. plus an extra 1 oz. (3 oz. total).

*There are circumstances where a particular system type will spec. a different distribution for the oil, based on the "method of loss" (major, minor, quick or slow loss). And, if you didn't flush out the entire system (of the old oil)........sometimes, you may have to use your best judgment, about what amount of oil you believe is still retained in the "other major parts" of the system.

Aloha, Mark

PS.........BTW, the book will tell you the TOTAL amount of refrigerant and/or oil, for the entire system.

Do the math (too much or too little oil, is not good).

 

[gmanpaint]

My 94 Ex has a stuck check ball on the fill side. It wont seal after I dump coolant into the system. It hisses like a pissed off cat. I tried to tap it with a nail punch, and it does make it slow, or speed up the leak, but wont stop. What do i do? I really need my a/c!

 

[ma96782]

gmanpaint,

WELL.......the "old" R-12 systems used a schrader style valve core. Which were easily found and replaceable.

But, as you probably know, the "new" R-134a valves are different. I'd guess.......that the engineers of the R-134a systems would have thought about......"What if," for a similar leaking problem.

Check this out..........

http://qualitytoolsforless.com/Product.aspx?ProductID=3828

And, the Haynes book did mention, "Defective fitting replacement."

So then, you might have to replace the entire hose (or metal line) with the attached fitting/valve........check with a well stocked auto parts store.

Aloha, Mark

PS......individual valve cores and replacement ports can be had at FJC Inc. Download the catalog.....

http://www.fjcinc.com/

 

[JimDi4]

I have a 1994 Ford f250 I started out with a non-working unit. I replaced the compressor (new one not rebuilt) new condenser, new manifold hose, Removed evaporator, flushed and cleaned reinstalled, removed and flushed liquid line, replaced orifice tube, and accumulator….Filled with oil, 3 ounces at evaporator, 4 ounces at pump, 1 ounce at condenser, 1 ounce at accumulator…I then evacuated system with a vacuum for one hour at 30 (I don’t have a digital vacuum gauge like you have)…So then it was time to charge complete system…I have access to a 33 pound r134a tank so I connected that up to my gauges. I opened the red gauge and bled out the hose then tipped the 33 pound tank upside down and opened up the valve wide open and watched the red gauge pressure go up…the blue gauge went up also to about 70 psi…(it was about 70 degrees outside)…I closed the valve on the tank thinking now the pressure is stable and then decided to charge the rest through the low side. I then tipped the tank right side up and opened it wide open…I started the car and watched the gauges and noticed the blue gauge climbed rapidly.. I waited a minute or so and then observed it almost peg the neddle on my blue gauge….This made me uncomfortable so I shutdown the car engine and decided to bleed off the high pressue, So I disconnected the yellow hose from the tank and bled off the Freon….I then started the engine again and blue gauge was still pegged. I bled off more Freon and then the blue gauge went down about 50 psi…I then noticed the red gauge was around 100…I watched the compressor cycling off and on due to low froen now, the gauge reading didn’t move…Actually I googled my gauge readings high – low pressure, low high pressue and it said my compressure is going bad…I figured I ruined the compressor by running the pressure too high…Was I wrong to open the valve on my tank wide open for both the liguid and vapor charge? I used about 2 pounds of Freon during this process…I need some advice before I try this again with my new compressor….


PS - I also saw on other websites state you should never feed liquid refrigerant into the high -side...Only the low side...Could this also have caused my problem?
thanks Jim

 

[gmanpaint]

gmanpaint,

WELL.......the "old" R-12 systems used a schrader style valve core. Which were easily found and replaceable.

But, as you probably know, the "new" R-134a valves are different. I'd guess.......that the engineers of the R-134a systems would have thought about......"What if," for a similar leaking problem.

Check this out..........

http://qualitytoolsforless.com/Product.aspx?ProductID=3828

And, the Haynes book did mention, "Defective fitting replacement."

So then, you might have to replace the entire hose (or metal line) with the attached fitting/valve........check with a well stocked auto parts store.

Aloha, Mark

PS......individual valve cores and replacement ports can be had at FJC Inc. Download the catalog.....

http://www.fjcinc.com/

I took off the cap and then the pc under it. the valve is diff then a schrader valve. It has a flat brass piston/washer looking pc with a spring around the end. It has a metal pc with sharp tabs on it that fits inside the fill cap thingy..lol, sorry. I tried to replace it with a normal valve, but no luck. In the process, I dropped the tab pc on the ground and lost it forever, sheesh. I am going to the parts store to see if they have a replacement, if not, off to the junkyard!




Ok, went to the local Pep Boys, and they had the stock replacement part for it for $7.oo. A/C will be back running by tomorrow! I will stop hijacking after this post. LOL!

 

[Glacier991]

The prohibition in feeding liquid through the high side is because you will blow up your can if the compressor is running. Yours wasn't. The high side IS a liquid side.... you didn't do anything that would have damaged your compressor if you ask me.

I'm wondering if you got the orifice valve in ok... I'm pondering this one.

 

[jgamarra]

How to find the A/C port for a Mountaineer 2003

I bought a kit to recharge my A/C (because it is not cooling enough). But the cap/clip from the bottle-hose doesn't fit in the port (I supposed this is the right port, next to the battery). I know I have to connect it to the low pressure port, but if it is not fitting is the right port?. The other one I can see is on top of a cilinder-can that I supposed is the compressor. I don't want even to touch that one.

Sorry for this simple question, but I read that it could be dangerous to choose the wrong port.
Thanks for your help.

 

[chipmiller2000]

Thanks a million. Very helpful.

 

[jgamarra]

How to charge the A/C in a Mountaineer

Finally, I got it!!! I was trying to charge the system in the wrong port (high pressure, next to the battery). That's why I couldn't connect the hose of the 134a can. We have to use the low pressure port.
I read one post here where somebody said something like this: " if you can not connect it that means it is not the right port..." The engineers thought about this when they designed the vehicle....
I looked for another one and I found one next the windshield washer tank. It was hiden... I connected the blue hose and perfect.... I charged my system, with no problems. Now my truck is cooling like a new car...

 

[mrchuckm]

Low-side coupler (blue) too loose when connected.

I bought a set of manifold gauges from harbor freight.
U.S. GENERAL A/C MANIFOLD GAUGE SET R134A
Model 92649

When connected, the low-side coupler (blue) wobbles very loosely so I can't get a good vacuum. Anyone else seen this? Ideas?

BTW, the high-side coupler (red) connects nicely.

'97 XLT AWD
5.0L V-8

Thanks!

 

[yellowford]

I'm going to be another person to thank you for this write up, luckily I had access to a vaccuum and full gauges. My ranger now blows ice cold.