Adding a bit freon to an AC system - JeepForum.com
 
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post #1 of 9 Old 06-17-2019, 01:37 PM Thread Starter
juan304
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Adding a bit freon to an AC system

2001 XJ Sport
191,000
AT
4WD

Last year my AC didn't work. I tried one of those PRO cans. No luck. Took to a service place. Tech said over filled, but no leaks. Cost $100. Ok, I guess I screwed up.

Now, the same thing.

Studying I see a lot of stuff that can go wrong. Given that I want to see if I can do this, and info I've gathered.

Please critique, but have mercy.

I can see no leaks. The compressor clutch does cycle. I can get manifold gauges from tool rental.

Questions:

1. Once hoses hooked up to car's low and high pressure side I'm certain I need to purge these lines. Should be able to quickly open then close the manifold valves. Therefore, any issue which is first, H or L? Once done all valves then closed.

2. Will hookup the Freon can to yellow hose, which is connected to manifold. Then open the can to allow coolant into yellow hose. To purge air slightly open the yellow line connection at manifold for gas to escape. I believe its best to close the can at this point.

3. Once can valve closed then slowly open both valves, one at a time, to read pressure. I would think gauges will show some pressure. If so, then this implies need to add? If zero, then I've a major leak?

THE HIGH PRESSURE VALVE CLOSED AT THIS POINT:

4. I came across the JEEP FSM from a forum: With engine at operating temp it said to bypass the clutch switch so that it runs all the time, AC on, full cold, fan full, recir on, windows down, with temp gauge in vent. Start engine, RPM to 1000, with AC clutch engaged. Then compare high and low pressures. Reviewing the chart shows my pressure should be, based on my current temp 80, low side at 32-41 psi and high side at 200-260 psi.

5. If below this then I would open the can valve, then low pressure side for 5 secs? Then close low pressure valve. Wait a few mins to read both sides? Then continue until pressure on low side is within range. With vent temperature at 44F

6. Hopefully achieved, then close H and L valves. Remove can and service line. Turn engine off. Reattach AC clutch connection.

7. Then remove the hoses, reattach port caps.

* Then a cold beer?

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post #2 of 9 Old 06-18-2019, 02:10 AM
lazyxj
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Location: Los Angeles
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Watch this video that explains the basics of charging the A/C system.

2001 Sport, 4" lift, 33 X 10.50 KOs, R.E. DB, R.E.-UCA, JKS-LCA, ACOS, 8.25-4.56-TruTrac, SYE, D-30 E-locker w/alloy shafts, Hidden M8000 winch, Vanco front and ZJ rear disc brakes, Lots of armor, Towing baseplate.
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post #3 of 9 Old 06-18-2019, 12:34 PM Thread Starter
juan304
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Lazyxj

TY for this video. Straight forward with important details. I can get all the stuff............but, I'm in a Catch-22. No service centers will empty my system. They state, "We remove your coolant, weigh it, then store it. We then vacuum and check for leaks. If ok, we then return your coolant adding the needed amount." This costs $100.

Is there a way to "check" system performance without dealing with service centers? In other words using the gauges.

Let me rephrase my question: How can I tell if the system is empty?

Again, TY
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post #4 of 9 Old 06-18-2019, 05:23 PM
lazyxj
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Quote:
Originally Posted by juan304 View Post
Lazyxj

Is there a way to "check" system performance without dealing with service centers? In other words using the gauges.
Let me rephrase my question: How can I tell if the system is empty?
The gauges can be used to see if the correct pressures are present, they should look similar to what you quoted in the first post.
"Then compare high and low pressures. Reviewing the chart shows my pressure should be, based on my current temp 80, low side at 32-41 psi and high side at 200-260 psi."

Along with a A/C gauge, use one of the online 134A pressure charts, or preferably the one in the FSM, to see the predicted pressures for various ambient temperatures. A instant read pocket thermometer is stuck into a dash A/C vent, to check the output temp. The FSM shows the expected output temperatures. It should be in the high 30s to low 40s.

If the pressures are in range and no cooling occurs, the metering orifice may be plugged. It's located in the hard line coming out of the condenser, into the evaporator. It's built into the hardline and isn't serviceable, the whole tube is replaced. Looks like this on my 2001.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

If the pressures on both the high and low side are low, it needs refrigerant. If low, it's leaking badly and should be resealed. You can use a leak detecting dye to locate the offending piece. It will show if the compressor is leaking from the front seal. If so, replace the compressor, along with the receiver. If going that far, disassemble and change out all the A/C o-rings, under the hood.

2001 Sport, 4" lift, 33 X 10.50 KOs, R.E. DB, R.E.-UCA, JKS-LCA, ACOS, 8.25-4.56-TruTrac, SYE, D-30 E-locker w/alloy shafts, Hidden M8000 winch, Vanco front and ZJ rear disc brakes, Lots of armor, Towing baseplate.
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post #5 of 9 Old 06-18-2019, 09:15 PM Thread Starter
juan304
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Lazyxj,

You've clarified several points.

Question 1: If system is low, and with can attached to manifold, then I could open the low side, for about 5-10 seconds, then close valve. Repeat until the pressures and temperatures are in range?

Of course this is like using AC PRO on low side. But, by using proper gauges and technique allows the whole system to be reviewed.

Question 2: If I replace the hardline, then I've opened the system. If so, then go with the video listed?

I now see why tech centers remove all coolant. Doing so assures proper amount returned.

I thank you a great deal.
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post #6 of 9 Old 06-18-2019, 11:27 PM
lazyxj
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Q1 Hook the can up to the center, yellow hose. Press the Schrader valve for a moment to purge the line.
Wear gloves and safety glasses Then start the engine and turn the A/C on. Then add the refrigerant, watching the gauges.
Q2 If the orifice hardline is replaced, yes, it needs the complete process. Change the receiver too.

The refrigerant charge is specified in ounces. My 2001 XJ needs 20-oz. I use a digital scale to measure how much coolant has been used, same method as the video.
The tech remove the refrigerant to comply with the law, not to determine the capacity, they have books/computers provide that information, along with what weight and amount of PAG oil to used.
A problem with leaky A/C systems is after a while and a couple of additions, you have no idea how much oil has leaked out of the system. As the refrigerant leaks out, so does the oil.

2001 Sport, 4" lift, 33 X 10.50 KOs, R.E. DB, R.E.-UCA, JKS-LCA, ACOS, 8.25-4.56-TruTrac, SYE, D-30 E-locker w/alloy shafts, Hidden M8000 winch, Vanco front and ZJ rear disc brakes, Lots of armor, Towing baseplate.
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post #7 of 9 Old 06-19-2019, 10:59 PM Thread Starter
juan304
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Lazyxj.

Thank you for added details.

I'll try this next week and advise.
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post #8 of 9 Old 06-20-2019, 12:01 PM
MaskedMallard
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Xj

Quote:
Originally Posted by juan304 View Post
2001 XJ Sport
191,000
AT
4WD

Last year my AC didn't work. I tried one of those PRO cans. No luck. Took to a service place. Tech said over filled, but no leaks. Cost $100.
By any chance is there a warranty on the work that was performed? Since you mentioned "last year", its possible there is a warranty on the A/C work that was performed. It doesn't hurt to ask the shop.

Out of curiosity, what is the outside air temperature when you are saying your A/C doesn't work? Do you have a thermometer to put in the center vents to read the air blowing from the vents? I use a $5.00 round analog meat thermometer I'd bought at the grocery store. I think the gauge can't be much bigger than a quarter.

2001 BJC Orvis XJ Build -
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post #9 of 9 Old 06-26-2019, 11:24 PM Thread Starter
juan304
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MaskedMallard, the previous work was only warrantied for 90 days. Outside temp is now at 90 and humid. Yes, have small thermometer.

Monday I got a set of gauges and hooked up to low and high side. With engine off, low at 75 and high at 125. With engine running, the low side cycled between 30-70, but high side wouldn't move. I engaged clutch full time. This brought high side up to 170, with no change in low side. Of course this is way off for high side. Vent temp at 70. I turned engine off and pressures remain fixed. Outside temp at 90.

With engine running I added coolant, by opening the low side for about 5 secs. Monitoring the pressure I raised low side to 40 psi, as clutch engaged. But, high side did not change, even after running for a few minutes. At that point I stopped, for I needed to know why high side remains low. I did not want to damage system.

Tuesday, I took Jeep for State annual vehicle inspection and noticed the small firm had a AC retrieval system. I asked for advice and he said, "let me take a look." After 45 mins he said, "A bit low, and added a few ounces." Given the time period I'm not sure he purged and vacuumed the system. Nonetheless its freezing cold now. He charged me $20. So, if low next year, then I'll repeat. I've known him for a long time and does good work.

A few things I learned:
1. Carefully check the AC gauge set you rent. Make certain that everything is there, especially manifold valves are not tight.
2. Make sure the connection to the coolant can is tight. As I turned the can the hose began to loosen the fitting.
3. Keep all your hoses well away from the belt assembly. The belt might catch a hose.
4. Place a cloth over the battery. Don't want "sparks".
5. Before connecting the L and H fittings make certain these are turned with plunger retracted. If not, then as you attach the valve it might depress the schrader valve and coolant will escape.
6. Once everything is in place, then slowly open H and L fittings. As soon as pressure shows, stop at that point. Opening more may damage the schrader valve.

Laxyxj is fully correct that the best way is to empty it, vacuum it, test it, and refill it.

I do have a question: Looking at auto store coolants there are many types and brands. Which one is best for JEEP AC systems?

Also thank you for your help.

Last edited by juan304; 06-26-2019 at 11:26 PM. Reason: correcting text
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