To check the auto a/c compressor compression ratio, note on paper the low and high side gauge readings and add atmospheric pressure to both readings. Divide the high side reading (with the atmospheric pressure added) by the low side reading (with the atmospheric pressure added).The result should be between 6.5:1 and 7.5:1. A compression ratio of 8:1 or higher may cause compressor failure. Learn More…
The A/C compressor is considered the heart of the refrigeration system. Compression ratio is the technical expression for pressure difference. Compression ratios are used to compare pumping conditions for a compressor and is an efficient way to evaluate the health of an air conditioning compressor.
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How to find an auto ac compressor problem, before is too late?
Check for high compression ratios. To check a/c compressor compression ratio, note on paper the low and high side gauge readings and add atmospheric pressure to both readings. Divide the high side reading (with the atmospheric pressure added) by the low side reading (with the atmospheric pressure added).The result should be between 6.5:1 and 7.5:1. A compression ratio of 8:1 or higher may cause compressor failure.
Normal noises of the A/C operation include the sounds of A/C compressor clutch engagement, the blower motor, moving blend air and mode doors, and pressure equalization after vehicle is shut down. By early identifying the sound of a bad ac compressor on the vehicle, could make a big difference in terms of labor time and price of the repairs needed.
Noises that could indicate the need for a/c compressor service or replacement include:
Growling noise with compressor disengaged
Growling noise with compressor engaged
Why is my AC making a weird noise?
Banging noise: If liquid refrigerant enters the compressor, a thumping, banging noise will result.
Knocking noise: Heavy knocking compressor noises come from refrigerant system blockage, incorrect pressures, or internal damage.
Growling noise with compressor disengaged: A worn compressor pulley bearing or clutch bearing will cause a growling noise.
Growling noise with the compressor engaged: A/C compressor internal bearings damage.
Squealing noise: A loose, dry, or worn A/C compressor belt will cause squealing noise. This noise will be worse during acceleration.
Worn or dry blower motor bearings may cause a squealing noise when the blower motor is running
Rattling noise: A loose or worn clutch hub or loose compressor mountings bolt will also cause rattling noise from the compressor.
Knocking noises: This type of noise from the compressor usually indicates internal damage, especially on piston-type compressors. Always check the compressor mounting and brackets before condemning the compressor for noise.
A loose mounting can cause knocking noises from the compressor area that may be mistaken for internal compressor noise.
Grinding noise: When car accessories pulley bearings are failing, they can make this kind of noise.
Do you need assistance checking the proper operation of your car ac compressor ?
How long should an air conditioner compressor last in a car?
The air conditioner compressor should last the entire life of the vehicle. The car ac compressor damage is usually a sign that something else in the cooling system or car ac system is not operating properly and is negatively impacting the auto ac compressor operation.
Inaccurate refrigerant(freon) charges increase the chances of auto ac compressor lock up. Modern auto a/c systems require super accurate charging. Being off as little as 2 ounces can cause problems.R-134a and R-1234yf ac system tolerances require charge rates that must remain or should be charged within +/- 5% of OEM recommendation. SAE J2788 requires charge accuracy of +/- one-half ounce.
Attempting to charge by cans is History !!
Car ac compressor lock up due to improper compressor lubrication.
Refrigerant moves the oil inside the ac system and helps to cool down the ac compressor. An undercharge or overcharge refrigerant condition will increase the air conditioning compressor temperature and a change in oil viscosity and lubrication characteristics. Most compressor lock ups are the result of a lubrication problem.
AC compressors lock up due to ac system contamination
Auto ac compressor damage may occur because of system contamination. Anything more than the correct type of freon and oil is a contaminant. The use of sealers to fix small refrigerant leaks will cause oil and refrigerant contamination and ultimately ac compressor lock up. Sealer can’t be removed from the A/C systems. The contaminated components must be replaced.
The use of excessive Dye to help finding leaks in the ac system could create a contamination problem as well, increasing the normal working pressure of the ac compressor and the overall efficiency of the air conditioning system.
Improperly replacing any component in the automotive air conditioning system where the system must be opened for replacement of the damaged part and not evacuating the system before recharging it with the proper amount and type of refrigerant will contaminate the ac system with air. Air and moisture inside the system will create excessively high operating pressures and temperatures and eventually could lead to a compressor lock up.
Inefficient ac condensers and air conditioning compressor lock up
Debris on the condenser will affect the desuperheat, condensation and subcooling processes happening in the auto ac condenser.AC condenser with bent or missing fins will be unable to efficiently operate. An inefficient ac condenser will cause an auto ac compressor to lock up.
Low Refrigerant charge and electronically controlled compressor lock up ?
The car engines in vehicles with the clutchless compressors should not be run without refrigerant in the A/C system. Without refrigerant to move the oil, the auto ac compressor may not be properly lubricated and compressor lock up may result.
Do you need assistance inspecting the state of your ac compressor in your vehicle?
Some compressor clutch circuits contain a thermal limiter switch that senses compressor surface temperature. Some A/C compressor clutch circuits also contain a low-pressure cutoff switch. These are auto ac protection devices and their goal is the auto ac compressor protection.
A/C safety switches .
A/C systems have load-sensitive electrical switches; such as the low-pressure switch, high-pressure switch, pressure cycling, and power steering. Not all the switches, however, are used in all vehicles. The pressure switches are used to prevent compressor or component damage in the event of extremely high or low-system pressures.
Do you need assistance testing your AC compressor protection devices ?