A/C Failure: Compressor Or Clutch ?

December 7, 2023

The air conditioning system on a vehicle has many components that work in concert with each other to deliver cool air. As we all know, ac compressor is the heart of car’s AC System and there are many blogs introduce AC Compressor or involve Common Air Conditioning Problems And Solutions, recommended reading: How To Buy a High Quality AC Compressor

What does an AC Compressor Clutch do?

The a/c clutch drives the a/c compressor, which sends refrigerant to the evaporator where refrigerant gets condensed. The refrigerant travels though the lines and is cooled by the radiator. Cool air gets blown through the air conditioning vents.

The a/c compressor clutch consists of three parts:

-The clutch plate connects to the AC compressor shaft and drives the compressor when it mates against the clutch pulley.

-The clutch pulley is rotated by the drive AC compressor clutch components belt when the engine is running and rotates around a pulley bearing.

-The clutch coil is a large coil of copper wire. When the clutch colit receives power, it will generates a magnetic field and pull a part of the clutch plate against the clutch pulley, causing it to rotate the compressor shaft.

It's every car owner's worst nightmare when the A/C couldn’t produce cool air in such hot days. Is there an easy way to confirm whether the A/C clutch failed or the compressor? This blog will tell you the answer.

Symptoms of a failing AC Clutch

•AC blows warm. Clutch is slipping and not providing greatest refrigerant compression.

•AC clutch won’t engage. Bad clutch coil or improper air gap

•AC clutch screeches. Rust accumulation on clutch plate and pulley or incorrect air gap.

Symptoms of a failing AC Compressor

•AC not working: no cold air or weak cold air flow

•Noisy from under the engine

•Oil or Freon leaks

How to Tell If the A/C Clutch or A/C Compressor Is Bad ?

Step 1 : Measure the battery voltage

Start your car and turn on the A/C controls. Open the hood and use the voltmeter to the volts of battery. When the ac system is normal working, the battery voltage reading is 12 volts. If there is the volts but the reading is below 12v, it means there is a internal short of ac clutch-the fuse or relay failed. If the volts reading is zero, go to the next step.

Step 2: Inspect the refrigerant pressure

Too high or too low pressure, the ac clutch of the ac compressor is not working. Start the engine and turn the AC controls on maximum. Open the high- and low-side knobs on the gauge. The low-side reading should state between 25 and 40 pounds per square inch (PSI). The high-side reading should fall between 200 and 225 PSI. If it reads outside of these limits, it means adding too much or too little refrigerant, the cutout relay inside the compressor is preventing voltage from activating the clutch.

Step 3: Check the circuit

Different models have different circuits as well as the different controls. It is better for you according to maintenance manual to check the circuit. If there is no problem with the circuit plus the coil has magnetic force, then consider the air gap between the clutch and the pulley whether is correct.

Sometimes replacing a new ac clutch is more affordable and reasonable. When it comes to quality A/C parts, we are proud to be your preferred project partner. You can visit Hex Auto Parts specialist about A/C Compressor and Clutch parts. 

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