A/C recharge question

[tony314]

My A/C system is empty ( has top remove compressor to change PS pump ) and I am wanting to recharge the system. Can I use the canned Freon to fully recharge an empty system and if so, how many cans for a 98 4.0 Ranger will it take?

 

[exbass94]

There should be a sticker on the radiator support that has the amount of refrigerant required. You need to have the system evacuated and get all the air and moisture out before you recharge it though.

 

[killj0y]

There should be a sticker on the radiator support that has the amount of refrigerant required. You need to have the system evacuated and get all the air and moisture out before you recharge it though.

Yea and use proper gauges so you can monitor the high side too did you replace the compressor? If so make sure there is oil in the system.

 

[custom '90 ranger]

If the A/C line have been disconnected from the compressor then a vacuum will have to be pulled on the system.

and to reiterate what was said before if you replaced the compressor, then compressor oil will have to be added to the system.

after you pull the vacuum on the system you are ready to add the freon but i DO NOT recomend putting the freon in yourself without the proper R134-a gauges so you can monitor the high and low sides of the system.

This is almost something that needs to be left to a professional (not saying that you cant do it because i do not know your skill level or experience) being a mechanic i have seen to many people try to do things like this themselves and end up hurting themselves by over pressurizing the system and having a line blow up in their face.

and on another side note be sure to only put the recommended amount of freon in because if there is just slightly to much freon then it will have a reverse effect and it will actually not cool .

Lucas

 

[kimcrwbr1]

Pressure test it with nitrogen first take it up to around 200 lbs and hold it for at least 45 mins you want zero loss in pressure. You can just soap test it at a lower pressure but the best is at operating pressure on the high side. You cannot charge it properly using pressures but you can get close estimating the charge by weight. While still in a deep vacuum after you added the oil add refrigerant on the low side with the engine running and A/C set to high when the low pressure limit switch closes the compressor will start. Keep adding refrigerant until you add close to what is on the sticker factory charge by weight. Let it run for about 20 minutes you want around 20 degrees between the cab temperature going into the blower and the temperature coming out the closest duct to the coil inside the plenum. pressure test, add oil, vac down ,add refrigerant. In that order.

 

[killj0y]

Buy some gauges they run about 50 to 100 for some ok ones to use at home and calibrate them first! Plus you know learn to read them too...

 

[aspevacek]

I do not think you need to put an ac system under pressure. It is harder to hold a vacum then it is to hold pressure. Pulling the system as close as you can to absolute vacum based on how far off sea level you are and then observe the guages over a 30 minute time preiod to watch for the needle to creep or loose pressure. The thing with holding a vacum on the system is, if there is a leak all the vacum will be gone very fast unless it is in a blocked off section of the system. In which case you have a bigger problem then trying to pull a vacum on the system.

 

[kimcrwbr1]

If it dont hold pressure there is no use in adding refrigerant unless you like throwing money away.

 

[press 1 for english]

I do not think you need to put an ac system under pressure. It is harder to hold a vacum then it is to hold pressure. Pulling the system as close as you can to absolute vacum based on how far off sea level you are and then observe the guages over a 30 minute time preiod to watch for the needle to creep or loose pressure. The thing with holding a vacum on the system is, if there is a leak all the vacum will be gone very fast unless it is in a blocked off section of the system. In which case you have a bigger problem then trying to pull a vacum on the system.

Why not just put half a pound of 134A into the system and check for leaks with a leak detector? Do it right or find someone who can.

 

[aspevacek]

With a leak in the system introducing Freon to the system will also allow it to escape into the air. If the system had a leak a leak detector can still pick up traces of the freon with out a leak present. Pulling th evacum should not cost you anything in terms of wasted freon. So I will still stand by the way I have done it for a long time in pulling the system under a solid vacum and letting it set for 30 minutes. No movement of the needle and the system is air tight. Like I said before it is harder to hold vacum then it is to hold pressure.

 

[sblake01]

Much of the advice I see here is good but it requires equipment and materials that the average do it yourselfer doesn't have. If the only reason it's empty is because you removed the compressor, it should still be vacuumed before you reacharge it. My advice would be to compare the cost of buying what you need to do it properly at home vs. having a shop evac. and charge it for you. Gauges, a vacuum pump, freon, pag oil, etc. would likely cost more than a simple evac/recharge at a shop. Also you asked about the system's capacity. It's 30 oz. for a 98 Ranger but you'd still be taking a chance if you don't vacuum it first and you wouldn't know the exact readings without gauges. Shame that you're like some 1800 miles or so away. I could help you out because I have all of that stuff at home.

 

[killj0y]

The tools the previous post mentioned are available at harbor freight, not the best but good enough for using it once or so a season. I got mine there (gauges and vacuum pump) for about 150. The freon and oil you can pickup at any auto store but around here dollar general and Walmart is the cheapest. You should change out the I ring on the compressor since you have/had it apart already too just preventative lol. I would probably like a few bucks anyways.

All in your probably looking at 200 for everything but you can do it again next time for the cost of just freon.