AC Compressor Leaking Green Fluid? 5 Reasons And Solutions To Fix It!

ac compressor leaking green fluid
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Nothing can be more comfortable than traveling in the car with your AC (Air conditioner) ON to your favorite destination, especially during the very cold winter or hot summer seasons.

The HVAC unit (Heating ventilation and air conditioning) plays a critical role in maintaining a peaceful and soothing atmosphere inside your car.

People often get irritated when the car AC suddenly breaks down and doesn’t operate effectively resulting in very poor or negligible performance.

Can you imagine driving without an AC in the car in extreme climatic conditions? No, isn’t it? But the experience would be similar to driving with ineffective AC performance.

The AC unit has got various parts starting from the compressor, condenser, expansion valve, and evaporator.

Out of all these parts, the compressor plays a key role in pressurizing the refrigerant throughout the HVAC circuit to keep the AC ticking, but it is also one of the parts that need critical maintenance since it has various moving and sealing parts to re-circulate the refrigerant in the circuit.

People often complain about one or more issues in the car ac compressor and 7 out of 10 times it is the issue of ac compressor leaking green fluid that concerns people.

The reason for the compressor leaking green refrigerant fluid can be attributed to the worn-out clutch or bent shaft of a bad compressor, bad compressor pulley bearing, worn-out O-rings, damaged refrigerant hose, and blocked expansion valve.

Is your ac compressor leaking green fluid? And you are interested in knowing the reasons and solutions to fix it! Then you are at the right place.

Here, in this article, you will get to know all the tips that you need to know while troubleshooting ac compressor that is leaking green fluid.

What Is The Green Stuff In AC Compressor?

Most vehicles nowadays use refrigerant R134a in the car ac unit. A refrigerant has an inherent physical property and is so cold that it boils even at sub-zero temperatures. It helps the refrigerant to absorb the heat from hot air inside the cabin of your car.

But the issue while dealing with the refrigerant is that it is typically, colorless gas and you can’t identify it with your naked eye but you can feel it since it is very cold.

Hence a green-colored UV dye is typically mixed in the refrigerant to trace leaks if any in your car.

People often ask what is the green stuff in ac compressor? The green fluid that comes out from the ac compressor is actually the refrigerant which is pre-mixed with the UV tracer dye to point out leaks.

The dye is easily traceable under UV or blue light or blacklight. You can just confirm this by spotting a UV light over the concerned leaking area. The refrigerant will glow green and shine bright.

And many times they mistake the green fluid as an anti-freeze coolant, but it is not. The green fluid leaking from the ac compressor is not an anti-freeze or engine coolant.

There is no way that an antifreeze coolant can spill over the ac compressor since the compressor is usually packaged on the sides of the radiator.

You may also notice that the antifreeze won’t glow under a blacklight wherein a refrigerant would!

How Does Car AC System Works?

It is essential to understand how does car ac system works before we proceed further to analyze the reasons for the ac compressor leaking green fluid.

This will help in understanding the causes of the issue and could arrive at the problem source.

A compressor is a unit that delivers the pressurized refrigerant all across the HVAC circuit to absorb the heat from the hot air inside the cabin atmosphere.

There are a series of parts that operates the HVAC unit of your vehicles like compressor, condenser, expansion valve, and evaporator which do their function in sequence.

It all starts with the compressor which compresses the refrigerant to a higher pressure gas. This increases the temperature of the refrigerant in addition to pressure.

The high-pressure gas is cooled off by the condenser fan which ensures a natural draft of air over the condenser fins to take out the heat from the high-pressure gas and convert it into a high-pressure liquid with a change in the refrigerant phase. This reduces the entropy energy of the refrigerant.

The high-pressure liquid is converted into a low-pressure liquid when the refrigerant passes through the expansion valve.

The sudden throttling of the liquid reduces the temperature of the refrigerant drastically when it enters the evaporator to make it capable to absorb the heat from the cabin air which is forced over the evaporator fins by the blower motor.

The blower motor either takes fresh air or recirculates the cabin air depending upon the circulation mode selected.

In the evaporator, the refrigerant in a liquid and low-temperature state absorbs heat from the cabin air and gets converted into refrigerant gas which is then pressurized in the compressor for the next cycle of operation.

This cycle keeps on continuing to ensure the required cabin air condition and temperature.

Is Your AC Compressor Leaking Green Fluid? 5 Causes And Solutions To Fix It!

If your car’s ac compressor leaking green fluid then there is some serious problem in one of the components, especially the compressor and its assembly parts. Below are the probable reasons for the ac compressor leaking green fluid and solutions to fix it.

Bad compressor

If the car ac performs fine while running the vehicle, but the ac performance deteriorates drastically in standstill condition, then it indicates that the compressor is going bad.Typically, a compressor has a clutch arrangement with a spline shaft that electromagnetically engages and disengages the compressor from the engine.

This operation is performed through an electrical switch which gets activated when it receives a 12 V supply to create an electromagnetic field inside the coils of the compressor.

The voltage supply is given to the compressor whenever we turn the ac ON through the user interface or a duty cycle controlled by the vehicle ECM (Engine control module).

The engine drives the compressor through a pulley and belt arrangement. The pulley rotates freely on the shaft of the compressor with the bearing at its pivot.

The electrical field pulls the clutch plate towards the compressor and thereby it engages with the pulley which is driven by the engine.

The compressor sucks in the refrigerant during suction stroke through an inlet port on the main casing and the piston-cylinder arrangement discharges the pressurized refrigerant gas through an outlet port on the compressor head.

Typically, there are no. of O-rings and gaskets which seal the refrigerant from leaking out of the main shafts, casing, and head sealing interface.

A bend in the main shaft will create a leakage at the interface between O-rings and shafts and the ac compressor starts leaking the green fluid (refrigerant) through the sealing joint.

Hence the reason for the ac compressor leaking green fluid may be attributed to a bad compressor that has a worn-out clutch that often deflects the main shaft. Hence it is necessary to replace the ac compressor clutch to prevent major breakdowns later with the help of a clutch holding tool and rebuild tool kit.

If you can see the accumulation of green refrigerant in and around the compressor, then it means there is considerable leakage of refrigerant that you need to fix before it damages the circuit and permanently affects the AC unit unless the bad compressor is replaced with a new one.

Apart from ac compressor leaking green fluid if the compressor is generating a squeaking noise and if the full ac recharge lasts only a couple of months, then it is time to replace the compressor without any second thought.

Bad compressor pulley bearing

If the pulley doesn’t spin freely on the compressor it usually is the result of a bad pulley bearing.

A damaged bearing would try to put load and slightly deflect the compressor main shaft and wears out the O-ring seal present at the main shaft and the ac compressor starts leaking green refrigerant fluid through the sealing interface.

You may also notice that the shaft wobbles loosely about the center. If the green refrigerant fluid is leaking from the ac compressor, you will immediately need to inspect them and replace the pulley with a new one if found damaged.

Otherwise, the compressor unit will possibly fail terribly and would result in costlier repair actions.

Usually, the pulley, bearing, and clutch if it goes bad, can be replaced with ease as long as you don’t touch the metallic gasket arrangement after the complete dismantling of the compressor.

Worn out and shrunken O-rings

Since there are no. of O-rings and cylinder head metal gaskets that are used on the compressor, it is obvious that a damaged or shrunken O-ring would affect its sealing performance.

If the ac compressor is leaking green fluid refrigerant, then it would mean that the O-rings are badly damaged or worn out.

The O-ring plays a key role in containing the green refrigerant fluid inside the compressor and ensures a leak-proof sealing interface.

These O-rings get worn out throughout usage and get damaged in the event of heavy deflection in the compressor shaft or a damaged pulley bearing and the ac compressor starts leaking the green fluid across the sealing interface unless the bad O-ring is replaced with a new one.

Once you dismantle the entire compressor along with its seals and O-rings, the biggest challenge people face is to ensure leak-proof sealing joints.

In the case of a bent main shaft, even a new seal would get damaged quickly and starts leaking green fluid refrigerant from the compressor.

There are fewer chances that you can reinstate the sealing joint to fresh condition. So it is advisable to replace the compressor with a new one, once the compressor is completely dissembled.

Damaged AC hose 

Often the serpentine compressor belt is packaged close to the refrigerant hose connecting the compressor to the condenser.

If the ac compressor leaking green fluid issue has arisen after compressor belt damage or replacement, it is possible that the timing belt when it got ripped off, would have damaged or slapped surrounding components like a refrigerant hose and thereby ended up spraying the refrigerant over the ac compressor which you may perceive as if the ac compressor leaking green fluid.

You may need to thoroughly inspect the drain lines, inlet, and outlet lines or fittings and replace the hoses if found damaged. Weak lines may get burst especially if the pressure load on the ac is more during the hot summer season

Blocked expansion valve or orifice tube

Have you checked the expansion valve in the circuit for any blockage? Whenever you are troubleshooting issues related to an ac compressor, it is essential to check the condition of the orifice tube.

Since a blocked expansion valve would increase the pressure on the compressor to an extent that the O-ring or metal gaskets in the compressor will not sustain the overpressure and the ac compressor would start leaking the green fluid.

Hence it is advisable to replace the blocked expansion valve or orifice tube with a new one to get rid of the problem.

The reason for overpressure in the refrigerant circuit can also be attributed to overload on the AC.

Especially it is true during the hot summer season when the pressure of the refrigerant increases considerably due to maximum heat absorption from the car cabin and would lead to the issue of ac compressor leaking the green fluid.

How To Diagnose AC Compressor Leaking Green Fluid?

Drain out the refrigerant carefully from the circuit without spilling it open to the atmosphere which leads to pollution concerns and recharge the ac circuit hoses with refrigerant to the point at least the compressor would start kicking in.

Start your vehicle and switch ON the AC and look for any leakage in the compressor area with a blacklight/blue light in a dark room.

You may inspect all the joints and sealing interfaces in the ac circuit to rule out issues in other areas apart from the compressor.

Alternatively, you may apply soap water at all joints of the ac unit circuit and look for air bubbles that indicate a possible leakage area of the refrigerant.

If the ac compressor is leaking green fluid, you could hear a typical hissing noise coming from the circuit line since the pressurized refrigerant would create noise while exiting the leakage area.

You need to listen carefully to notice the noise. If the leakage is sufficient enough you may start seeing ac compressor leaking green refrigerant.

Final Thoughts

The green fluid coming oozing out of the ac compressor is nothing but the ac refrigerant with UV tracer dye to detect leaks.

A bad compressor with a worn-out clutch or damaged pulley bearing often would deflect the main shaft and wear out the O-rings and seals.

A damaged O-ring seal or metal gasket would affect the leak-tightness of the sealing interface that would cause ac compressor to leak green fluid.

You may inspect and replace the O-rings or shaft seals at the inlet and outlet shaft lines of the compressor to prevent leakage of refrigerant.

You would need special tools to replace the shaft seals. Also, the seals usually need to be replaced once it is disturbed from the assembled position.

It is necessary to follow the leakage path to pinpoint the exact leakage location to confirm that the green refrigerant fluid leakage is not from other areas of the circuit.

But many times, the leaked green refrigerant fluid falls on the timing belt and splashes all around and you may lose the source of leakage.

If you have disassembled the compressor from the motor for some reason, then there are chances of leakage at the compressor shaft seal ends or metal gaskets even after replacing O-rings or metal gaskets, since there is a very less success rate of reinstating the sealing interface.

Depending upon the criticality of leakage, you may either need to replace the compressor with a new one or follow the leakage path to find out the source of leakage other than a compressor.

We have tried to collate all reasons for the issue of ac compressor leaking green fluid and the solutions to fix it. Hope with this information hand you will be able to make a well-informed decision.

Happy Motoring!




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