Rick's Free Auto Repair Advice

Flush auto AC condenser

Can you flush an auto AC condenser?

Shop says they can’t flush the AC condenser. True?

I hear this all the time and the answer depends on the type of condenser in your vehicle. Older vehicles used tube and fin parallel flow condensers and you can flush an auto AC condenser on older vehicles with an AC flushing kit and tool. Unfortunately, tube and fin condensers aren’t nearly as efficient as newer serpentine and microchannel condensers, so carmakers switched in later years to improve AC efficiency. Most serpentine condensers can’t be flushed because the flat tubing is too small to flush effectively. Late-model vehicles use flat tube microchannel condensers that simply can’t be flushed; they must be replaced.

serpentine condenser
What is a flat tube microchannel auto AC condenser?

The whole point of a condenser is to place as much refrigerant as possible in contact with the airflow in order to remove heat. Flat tube microchannel condensers do that much better than tube and fin and serpentine style condensers. The flat tubes are extruded with very small passages that excel at heat removal. That’s the good part. The bad part is that the microchannels are so small, they clog with system debris and sludge and that material can’t be flushed out simply because the passages are so small..

microchannel condenser
What causes an AC condenser to clog?

Auto AC systems use rubber hose and seals and plastic parts. The AC compressor experiences wear over time and produce metal particles. Also, air and moisture in an AC system react with the refrigerant to form acids and sludge that deposit in the condenser because it’s right after the compressor. In other words, the condenser, orifice tube screen, and expansion valve each act as a trash collector for the AC system.

So you have to replace the condenser if the compressor fails?

Pretty much. Most compressor manufacturers require not only a condenser replacement but a receiver dryer replacement as well in order to maintain the factory warranty. They simply don’t want any debris breaking loose and damaging the compressor.

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Posted on by Rick Muscoplat

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