Rick's Free Auto Repair Advice

AC condenser test — automotive AC

Car AC condenser test

A restricted AC condenser can cause high pressures and compressor shut down, along with no cooling.

A condenser can be restricted internally or externally. It sits in front of the radiator, so start by checking for an accumulation of bugs, dust, leaves and other debris on the front of the condenser.

Check the front of the AC condenser

Pop the hood and use a flashlight to check for debris on the front of the AC condenser. If you find debris, spray it with household cleaner and then hose it down. Do NOT use a high pressure washer on an AC condenser; it will damage the cooling fins.

clogged AC condenser

Clogged AC condenser. This condenser can’t properly cool the refrigerant

Test car AC condenser for an internal restriction

With the engine and AC running in MAX mode, feel the temperature of the discharge hose. The discharge hose goes from the AC compressor to the AC condenser. The hose should be very hot.

Next feel the liquid line leaving the condenser; the one that heads up to the firewall. Compare the temps. The temperature should not drop more than 25°F.

If you feel a major temperature change across the condenser, the condenser is obstructed. Due to the use of micro-channels in modern condensers, they can’t be flushed, they must be replaced.

microchannel condenser

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Posted on by Rick Muscoplat

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