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“That” isn’t some unnamed mystery. Some shops still use R-11 and R-113 as flushing agents (they haven’t been produced in eons in the U.S., but there seems to be a lot around). These flushes worked great on CFC-12 systems, but when some early attempts at retrofit to HFC-134a failed miserably, one cause was trace amounts of them. R-11 and R-113 are considered “secret weapons” pulled out and used for some really contaminated HFC-134a systems.

The technician figures they were great on those old CFC-12 systems, so they also will really clean up total failures today. Ditto for some aftermarket flushes, but with a somewhat different slant. Reputable aftermarket flushes may be helpful with minor amounts of debris and oil removal, particularly those used with closed-loop flushing machines and air purges. Shops see they remove debris and push the envelope.

But when it comes to a catastrophic failure, even R-11 in the CFC-12 days often wouldn’t do the job, and the condensers of the CFC-12 days had much larger tubes than today’s models with passages the diameter of a toothpick or smaller. When reputable aftermarket suppliers today talk about catastrophic failures, they typically have a long list of parts to replace, and filters to install. They may recommend their flush only for some parts of the job.

Doesn’t Ford recommend a specific terpene flush for catastrophic failures? Within certain limits, yes, but only as part of a comprehensive procedure, which we’ll talk about in “CLASSIC CASE,” the case history of a late model Ford rear-drive car (Crown Victoria/Grand Marquis) that follows.

Ford’s flushing procedure is specified with a particular flushing machine, with a lengthy air purge. Does that really matter? Yes, if you plan to use a Ford shop manual procedure on a Ford vehicle. Ford never tried any aftermarket flush and doesn’t know under what conditions it works and doesn’t work for major contamination, or what procedure might be required. When Ford validated its flush, it determined the amount of time needed to circulate the solvent for debris removal, it tested the air purge procedure often enough to be sure that only the most minor trace might be left in, and that the trace did no harm.

Further, as Ford condensers went through design improvements, with tinier passages and more flow paths,

Ford recognized that with catastrophic failure it might not always be possible to include the condenser in that flushing operation, in which case replacement was necessary.

So as noted earlier, shops that don’t replace with an OE level condenser, could see higher-than-normal head pressures and in hot weather, premature compressor failures. If you don’t put price first, you can get OE-level condensers, and many shops do, from reputable suppliers. But we find out about shops that do so many things so well, but take shortcuts when dealing with catastrophic failures. We understand the impetus: many parts to replace, much work to do, and the price edges up to the area where there’s

customer resistance. So using some cheaper parts lowers the total, whether it’s with the condenser, a questionable compressor, a make-it-fit evaporator and an old favorite: flushing hoses with mufflers, instead of replacing them.

Hoses with mufflers can’t be flushed successfully. To quote Ford: “hoses without mufflers can normally be reused unless they are clogged with foreign material...Install new refrigerant hoses with mufflers if clogged with foreign material.” You can’t tell without cutting apart, so just replace.

Another approach that’s even worse: just blowing shop air through the hoses, and when the air comes out the other end, deciding to re-use the hose – sorry, shop air (or dry nitrogen) through a hose isn’t flushing. But even a flushing agent blown out of a spray gun may not completely clear a hose after a catastrophic failure. It’s not that the hose still is packed—it probably isn’t, but as the remaining debris flakes off from the walls of the hose, and gets carried to the compressor (or even as far as the expansion valve), it’s not going to improve compressor life or performance. That’s why cautious shops that flush suction hoses also install suction side screens.

Remember the old problems with suction hoses in which the inner liners collapsed? You could cut those things apart and see the necked-down areas, but you might find it hard to believe the seemingly small amount of reduction in diameter was responsible for major loss of performance – but it was.



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