How do you bleed air from the cooling system of a dodge truck?

Answer 1

You first recover the refrigerant with a refrigerant recovery system designed for the refrigerant in use.

You then use a vacuum pump to draw a vacuum in the system. Connecting all of your filling equipment before you draw the vacuum, so that you vacuum out the lines of the filling equipment. Once the desired vacuum is established, and it is holding the vacuum, you can then fill the system with refrigerant.

This is an overview of the process. I leave out things like checking for leaks first, changing out the orfice, the dryer, etc... Each system has a different design, and requires a slightly different repair procedure.

Unfortunately, the fact that you asked the question indicated you probably don't have the tools to do this right. But it is possible to do this with only a couple of the right tools. a set of gauges, a charging cylinder, and a vacuum pump are the minimum tools. Have someone recover the old refrigerant before you start (this is legally required).

Use the charging cylinder to put the correct amount of refrigerant into the system... Guessing is never a good idea, and no, you can't tell how much to put in with a gauge. Since the refrigerant turns into a liquid under pressure, a gauge only tells you the temperature of the liquid, it does not tell you if you have enough or too much.

If you put in too much, you may damage the compressor, too little and the system may not work well.

Many people do their own AC work, and without the right tools and know-how, the job produces less than satisfactory results. A small amount of air in a system will rob it of 90% of it's performance and cause a large amount of strain on the system's high-side components. Some systems will detect excessive head pressures, and shut the compressor off intermittently. Eventually the compressor valves will fail prematurely.

Air in the system may mean a leak has developed on the low-pressure side of the system, or that the system was opened to the air during service. It is not possible to purge air properly without a vacuum pump. Some people try to purge by bleeding one side while filling the other side, and that can remove some air, it won't get it all... and it won't get the moisture. It is more important to get the moisture out, moisture is always sucked in with any air.

I would suggest that you invest some money in getting trained, then buy the correct tools. The tools can cost less than getting the unit serviced by a pro, and the training will make you a pro.