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Keep in mind when reading the following is that I'm all about Do It Myself.
My AC system is completely disassembled, refurbished, cleaned, repainted, polished, and ready for reassembly and recharging with R134A. Two things concerned me because I lack the necessary equipment: flushing out the evaporator and condensor, and drawing a vacuum before recharging. The clearing out of most of the prior R12 oil I understand. Pouring any number of solvents (someone suggested mineral spirits) through it is the correct proceedure, but to flush it proper would require an air compressor, which I don't have. So I came up with this borderline white trash scheme, and it worked!
I knew I didn't need all that much force of air to flush out whatever solvent I poured in through one side of the condensor. Could I possibly use the engine vacuum and just have it burn up whatever comes out of it? Sure, why not! (*see below for footnote) So I rigged up a series of hoses and fittings so that one end of the condensor fitting connected to the aux air hose connection on the throttle body. Then with the condensor propped up vertically on top of the engine, I started the car up. The engine idled slightly higher from the additional air being drawn through the condensor. Then with a funnel and hose connected to the other condensor fitting, I slowly poured in about a cup of mineral spirits. The engine sucked it through the condensor and ate it up, mineral spirits, old charge oil and all. The engine did bog down a bit, and some smoke blew from the tailpipe for a time, but after 30 seconds of manual acceleration, all was normal. Then I followed the mineral spirits flush with an acetone flush. With acetone, the engine rpms die down quite a bit, more than likely because the O2 sensor reads rich and tells the modulator valve to ease up on the fuel. But once that stuff cleared the intake system, all was fine. I did the mineral spirits/acetone flush one more time, with no additional smoke (from old charge oil) during the mineral spirits flush phase.
I'll do the same with the evaporator tomorrow before I reattach everything.
The only thing that concerns me with this entirely DIM AC refurbishment process is being able to draw a vacuum once the system is all sealed up. I'm sure I could find someone to do it proper, but that just goes against my nature. The vacuum is necessary, as I understand it, because of unwanted atmospheric moisture and air, which may decrease the coolant efficiency and hasten corrosion. If I can figure a way to draw a vacuum using the engine vacuum system...
* Before I just let the engine burn whatever came out of the condensor, I first did a manual pouring of mineral spirits in one end, tossed and shook it about, then drained it and blew air into one end with my mouth. Nothing frightening came out other than some oil and the mineral spirits, so I was confident I wasn't going to harm the engine with rust or gunk when using the above flush method.
posted by 205.188.199...
, Fri, 10 May 2002 22:53:51
, Fri, 10 May 2002 08:16:27
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