A/C flush...how?
 

My system was inop for several years until I finally fund a bad hose and charged it up. I replaced the orafice tube but I believe that it is clogged again (i have noticed that the oil is particularly dirty). I know I should have done it before but that was then and this is now, etc., etc.I have read here that acetone or paint thinner is the solvent of choice but my question is this: Do i have to disassemble the entire system to flush it? How will i flush out the compressor? If i dump a bunch into the condensor will I be able to get it all out without removing it?

Any and all help/advice is appreciated.

You cant Flush an A/C system all you can do is replace the system parts and recharge and vaccum test with the machine used to service A/C systems which is about 1600 bucks minimum. If you used a air hose and blow out the system it will be contaminated no matter what and will not work properly.
If you say the oil is dirty I suggest you just get it to a shop that is well know for good work and replace Condensor, Evaporator, Reciever drier and so on. Depending on the year (hopefully not R12 have fun buyin that) '93 or '94 til present is R134A. A/C system servicing is somethin a certified tech should be doing not the regular person. But choose what you want to do exactly first.

Of course you can flush an AC system. Read the service manual! My vacuum pump cost $100. Where did you get a figure of $1600?

Evaporator and condenser coils and the various lines can be flushed. The O-tube, mufflers, and the compressor should NOT be flushed. Condensers are best replaced if the system had a compressor explode.

Laquer thinner makes a decent flush agent. It's cheap and readily available. Needs to be shot through the system under some pressure, so a flush bottle is needed. Dry shop air can then be used to expel all the flush agent. Reassemble using new o-rings and the proper oil, then evac the system to boil off any moisture. If no leaks, follow up with a charge of the proper amount of refrigerent.

Steve

flush cans work great. I bought mine for about 100 bucks. I have found that acetone works very well. however if you charge the flush can with compressed nitrogen rather than shop air you can reduce your vaccum time by half. pull the oriface and re install your liquid line. I believe that your truck has a muffler in the suction line. sometimes those can hold contaminates. replace your drier(usally about 50 bucks) and all your o-rings.good time to retro if your interested. but thats another story. good luck.

It has already been retroed but again, i think there is just too much garbage in the system. I had the compressor, drier, and the high pressure line replaced about 9 years ago, and replaced the liquid line and the orafice tube this summer. it worked "ok" for about 3 months, then crapped out again. I tried to give it a charge but it wouldn't really take any more refrigerant and doesn't get cold. Hence, i think that the orifice tube is clogged from all of the junk in the system. If i wimp out, how much do you think a shop would charge to flush and refill the system?

$2-300 provided nothing else needs done for a thorough service including flush, drier, and o-tube.

I got the figure from being taught with the big machine that shops use for recharge and vaccum testing which is about 1600 bucks. I just thought of to save you money also try a TECHNICAL SCHOOL because THEY CAN NOT CHARGE FOR LABOR cause they are learning so all you are paying for is the R134A and parts, AND the intructior over looks to make sure they did it right. Try that b4 you call the shop.

1 more idea that you might try is if your manifold guages have a sight glass in them, than hook them up and open both hand valves and watch the refridgerant. if it has a milky look to it then your desicant bag in your drier has burst. just an idea. by the way, what makes you think that the oriface is clogged? is there very heavy frost at that point.what is your guage readings and ambient temp?