a/c system flush.

first off. you drain the oil. in a measuring cup so you know exactly how much oil came out and exactly how much to put back in. so that means tearing everything down.

fill the unit up with flush solvent. shake unit around vigorously for a few minutes. drain solvent and let air dry. you can blow compressed air but you won't get all the nooks and crannies. but it'll dry faster.

make sure to use fresh green o ring seals. coat them with oil before installing on systems and connecting the lines. you won't risk tearing the seals when connecting the peices.

oil goes in the condensor. the receiver/drier. and the compressor.

if the blower motor isn't noisy there's no reason to replace that. and no reason to replace the wheel unless it's broken. or lost it's weight for balance.

or why your overhauling the entire system. when you had everything working before.

 

The idea of a flush to have get the system as pure and clean as possible. Doing wrong with the wrong chemicals is only counter productive. To properly flush a system you should use a/c system flush fluid. It is designed to clean the a/c in such a way to leave minimal residue behind that is detrimental to a/c performance. Remember, you are trying to keep the amount of contaminants to a minimum or eliminate them all together. Never use shop air for this. Again, you want to reduce the chance of introducing contaminants and pollutants to the system as much as possible. The air from your shop compressor is actually quite dirty as far as an a/c system is concerned. There are oil and moisture residues that will cause problems in your system. Your receiver dryer is designed to filter this stuff out. But why put it there, if by accident, in the first place if you don't have too? Also, condenser and evaporator flushing is iffy at best. There is no way to 100% clean them out, other than replacement. Flushing them due to system contamination such as wrong type or too much oil is ok, but if you had a compressor failure with metal flakes you would have to replace them.

 

You would only have to replace if you had a compressor failure and metal got into the system. Nitrogen is easy to get. Lots of shops use it. It would just be an issue of getting the right adapters and pressure regulators to blow everything out. Nitrogen is also used for pressure testing the a/c system, so it is good to have. We get ours from the same place we get ouracetylene and oxygen for the torches.

 

you get better results with virgin freon. i've never had good luck with recycled freon. and i'm a retired mechanic.

it'll work. but not as good as virgin. i've used it for topping off purposes. but not a full blown recharge.

 

You want to careful when working on AC systems if you have never done them. If the system was working before you took it a part, a simple charge would be all you would have needed. As long as the system is charged and has the proper amount of oil it will run forever. Taking the system apart as you are doing can introduce water into the system and you don't want that. Yes you will have to use nitrogen to blow out the system and a vacuum to vac it down before you recharge it. You will also need the proper oil and the exact amount. Also a way to put the oil back in the system. On the truck it should have a label that has the weight of Freon and amount and type of oil. Good luck