20Y-979-6121 ST170206 10S15C 24V A/C Compressor for Komatsu PC200 PC300

20Y-979-6121 / ST170206 10S15C A/C Compressor for Komatsu Excavator

The 20Y-979-6121 / ST170206 10S15C A/C compressor is used in the cabin air conditioning system of Komatsu excavator applications. It is a 24V air conditioning compressor commonly referenced for Komatsu PC200 and PC300 series machines, including PC200-7, PC300-7, PC200-8 and PC300-8.

This product is supplied for repair shops, equipment owners and parts distributors who need a replacement A/C compressor for Komatsu excavator cabin cooling systems. MOQ is 1 piece, standard warranty is 6 months, and normal lead time is 7 - 15 days depending on current stock and shipping method.

Product Information

• Part Number: 20Y-979-6121 / 20Y9796121

• Reference Number: ST170206

• Compressor Model Reference: 10S15C

• Voltage: 24V

• Application: Komatsu excavator cabin air conditioning system

• Main Model References: PC200-7, PC300-7, PC200-8, PC300-8

Cross Reference Numbers

Common reference numbers may include 20Y-979-6121, 20Y9796121, 20Y 979 6121, ST170206, 10S15C, 447220-4053, 447220-4052, 20Y-810-1260, 20Y8101260, 4436025, 4431081, DCP99821, 421-07-31220 and 421-07-31221.

These numbers should be used as reference numbers only. A/C compressors with similar part numbers may have different clutch diameter, pulley type, voltage, hose port direction or mounting configuration. Final fitment should be verified by the original compressor label and machine serial number before ordering.

Application and Fitment Reference

This 20Y-979-6121 A/C compressor is mainly listed for Komatsu excavator references such as PC200-7, PC300-7, PC200-8 and PC300-8. Other public supplier references may also list related Komatsu Dash-7 and Dash-8 excavator models, including PC130-7, PC160LC-7, PC200LC-7, PC210-7, PC220-7, PC270-8, PC350-8, PC400-8 and PC850SE-8.

Because compressor configuration can vary by machine version, production year and previous repair history, the model list should be treated as a fitment reference. Please confirm the old compressor part number, voltage, clutch diameter, pulley groove, mounting points, hose port position and machine serial number before purchase.

Technical Notes

This compressor is commonly associated with a 24V excavator A/C system. Some references list R134a refrigerant, PAG 46 oil, a 152 mm clutch diameter and 1-groove V-belt pulley configuration. These specifications should be checked against the old compressor before ordering, especially when the machine has been repaired or modified before.

Common Failure Symptoms

• No cabin cooling: the A/C system runs but does not produce cold air.

• Compressor clutch does not engage: possible causes include low refrigerant charge, wiring fault, pressure switch fault, clutch coil failure or compressor damage.

• Abnormal noise: bearing wear, pulley misalignment, low lubrication or internal compressor damage may cause noise.

• Oil or refrigerant leakage: check hose connections, O-rings, compressor body, shaft seal and service ports.

• Repeated compressor failure: contamination, incorrect oil amount, blocked condenser, failed receiver drier or poor flushing may damage the replacement compressor.

Troubleshooting Before Replacement

Before replacing the A/C compressor, inspect the complete air conditioning system. A compressor failure may be caused by problems outside the compressor itself.

• Check refrigerant pressure and confirm whether the system has leakage.

• Inspect compressor clutch operation, belt tension and pulley alignment.

• Check the A/C fuse, relay, pressure switch and wiring connector.

• Inspect the condenser, receiver drier, expansion valve and evaporator for blockage or contamination.

• Confirm the correct refrigerant and compressor oil specification before installation.

Installation and Maintenance Notes

• Recover refrigerant properly before removing the old compressor.

• Inspect and flush the A/C system if the old compressor failed internally or if contamination is found.

• Replace the receiver drier or accumulator when replacing the compressor.

• Check whether the expansion valve or related components need replacement according to the system condition.

• Use the correct refrigerant and oil type specified for the machine and compressor.

• Rotate the compressor by hand before startup when required by the installation procedure.

• Evacuate the system, check for leaks and recharge with the correct refrigerant amount.

• After installation, run the A/C system and check cooling performance, abnormal noise, clutch operation and leakage.

Fitment Check Before Ordering

To reduce wrong orders, please send the machine model, serial number, old compressor part number, compressor nameplate photo, clutch and pulley photo, rear port photo and mounting photo before quotation. This helps confirm whether 20Y-979-6121 / ST170206 10S15C is suitable for your Komatsu excavator.

FAQ

Is 20Y-979-6121 an air compressor or an A/C compressor?

20Y-979-6121 should be described as an A/C compressor or air conditioning compressor for the cabin cooling system. It should not be written as a general air compressor.

Which Komatsu models commonly use this compressor?

Common model references include Komatsu PC200-7, PC300-7, PC200-8 and PC300-8. Other public references may include PC130-7, PC160LC-7, PC200LC-7, PC210-7, PC220-7, PC270-8, PC350-8, PC400-8 and PC850SE-8. Final fitment should be verified before ordering.

What are the cross reference numbers for 20Y-979-6121?

Common reference numbers may include ST170206, 10S15C, 20Y9796121, 447220-4053, 447220-4052, 20Y-810-1260, 4436025, 4431081, DCP99821, 421-07-31220 and 421-07-31221. These numbers should be checked against the original compressor label and physical configuration.

What should be checked before ordering this A/C compressor?

Please check the old compressor part number, voltage, clutch diameter, pulley groove, mounting points, hose port position and machine serial number. Clear photos of the compressor label and ports are recommended.

Should the receiver drier be replaced when installing a new compressor?

In most A/C compressor replacement procedures, the receiver drier or accumulator should be replaced, especially if the old compressor failed or contamination is present. The A/C system should also be inspected and flushed when required.