I was having a problem with the AC in my 1997 Accord recently. My dealer did an evac and recharge, found a leak, and replaced the compressor. Then they said the system was over-pressurizing, so they vacuumed the system to try to remove any clogs in addition to doing another evac/recharge. They said it was a bit better after that, but the pressure is still too high, and they think there is contamination throughout the system and recommended replacing everything.

I did a search and see it's possible to flush the AC system. However, I found a video that says a flush won't work on a "modern" car because the holes in the condenser are too small. Will a flush work on a 1997 Accord?

  • True, modern condensers can no longer be flushed, but this design did not start until about 6-8 years ago, so yours can be reverse flushed.
    – Moab
    Commented Jul 15, 2019 at 15:57
  • youtube.com/watch?v=U0O1mcnwjZs
    – Moab
    Commented Jul 15, 2019 at 16:00

1 Answer 1


It's a 1997 car so most definitely R-134A. Automotive R-134A-from-factory systems are fitted with parallel flow microchannel condensers, since R-134A has much higher saturation pressures compared to R-12. These condensers require very expensive and specialized equipment to be flushed and most of the time it's cheaper to just replace them. The reason why there's no need to replace an evaporator unless it leaks, and there's no need for specialized equipment to flush an evaporator (an aerosol flush may suffice if used properly), even though it's still a parallel flow heat exchanger, is that the condenser, the receiver dryer and the expansion device all act as filters for it, so you basically always flush only the old oil out of evaporators, even whenever a compressor seizes.

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