The genuine XCMG Viscous Clutch with OEM number 800172875 is a thermostatic fan drive engineered for XCMG articulated dump trucks, wheel loaders, and off-highway equipment. This clutch uses silicone fluid to engage and disengage the engine cooling fan based on actual cooling demand, reducing parasitic power loss, saving fuel, and lowering noise. Manufactured with a precision valve, bimetal temperature sensor, and high-strength aluminum housing, the XCMG 800172875 viscous clutch delivers reliable fan speed control, extends belt and bearing life, and ensures optimum engine temperature in the most extreme mining and construction environments.
The XCMG Viscous Clutch 800172875 modulates fan speed according to actual cooling demand, rather than running the fan at full speed continuously. When the engine is cold, the clutch “slips,” allowing the fan to turn at a low speed (approximately 10-20% of pump speed). As the radiator discharge air temperature rises, a bimetallic coil valve opens, allowing silicone fluid to flow into the working chamber, increasing fan speed proportionally. This on‑demand operation reduces parasitic horsepower consumption by up to 6% at highway speeds and improves fuel economy by 2-4%.
On AD60 and AD80 articulated dump trucks, the 800172875 clutch is mounted between the water pump pulley and the fan. Field data from mines in Western Australia shows that using a genuine XCMG viscous clutch reduces engine power loss by 15 kW (20 hp) and saves over 2,000 liters of fuel per year per truck, compared to a direct‑drive fan.
The clutch contains a bimetallic temperature sensor that reacts to air temperature passing through the radiator. As the air warms, the bimetal coil expands, rotating a valve shaft. This opens a port that allows high-viscosity silicone fluid to enter the shear gap between the driven and driving plates. The fluid’s shearing resistance transmits torque to the fan hub. The valve is precisely calibrated to begin opening at 85°C and be fully open at 95°C, providing a smooth, progressive engagement without sudden load shocks.
The silicone fluid is a specially formulated dimethylpolysiloxane with a viscosity index that remains stable over a wide temperature range. It is non‑flammable, non‑corrosive, and has a long service life. The fluid is sealed inside the clutch and should never require topping up. Any leak indicates a failed seal and requires clutch replacement.
The XCMG viscous clutch 800172875 is a direct OEM replacement for original part numbers 800172875A, 860124581, and 860298755. It is designed to fit the specific hub offset and bolt pattern of XCMG‑manufactured fan blades. The clutch housing has a standard 160 mm bolt circle for four M8 studs. Always verify fan blade compatibility before ordering – AD60 uses a 7‑blade, 780 mm fan; AD80 uses a 9‑blade, 850 mm fan.
The clutch includes a pre‑filled silicone fluid cartridge; no fluid handling is required during installation. The bearing is factory‑greased and sealed. The mounting nut is torqued to 150 Nm ± 10 Nm on the water pump shaft. The fan blade bolts should be torqued to 35 Nm using a torque wrench.
To replace a failed viscous clutch, first remove the fan blades (use a fan clutch holding tool to prevent rotation). Loosen the center nut (large M30 or 1-1/4″ hex) using a breaker bar. Remove the old clutch from the water pump shaft. Clean the shaft and inspect the bearing for roughness. Install the new XCMG 800172875 clutch by hand‑starting the nut. Torque the nut to 150 Nm while holding the clutch housing using a strap wrench.
Reinstall the fan blade, torquing the four M8 bolts to 35 Nm in a cross pattern. Start the engine and allow it to warm up. Observe the fan: when cold, the fan should spin at a low speed (you can see the blade blur). As the engine reaches operating temperature (85°C+), the fan should audibly increase speed. It should reach full speed by 95°C.
If the fan never engages (always slow), the clutch may be stuck in disengaged mode – replace it. If it runs at full speed all the time (roaring noise), the valve may be stuck open – replace it. If it leaks silicone fluid (oily residue around the seam), the seal has failed – replace immediately, as fluid loss will cause overheating.
Counterfeit viscous clutches sold as 800172875 often use low‑grade silicone fluid that thickens or thins at wrong temperatures, causing erratic fan speed. Symptoms include fan roaring constantly (high fuel consumption) or never engaging (engine overheating). Genuine XCMG clutches have a laser‑etched part number on the housing, a bimetallic coil with a green paint dot, and a holographic label on the box.
Another common issue is poor bearing quality. Aftermarket clutches may use unsealed bearings that fail early, causing fan wobble and noise. Genuine XCMG bearings are double‑sealed and 100% noise‑tested. Spin the clutch by hand – genuine ones are smooth and silent; counterfeits may feel rough or have axial play.
Temperature response: Counterfeit clutches often have incorrect valve calibration, causing engagement at 65°C or 105°C. Test the clutch by heating the bimetal coil with a heat gun; genuine clutches begin to resist turning at approximately 85°C (coil surface temperature).
A properly functioning viscous clutch can reduce fuel consumption by 2‑5% compared to a fixed fan, and by 10‑15% compared to a constantly running electric fan. For a truck consuming 30,000 liters annually, a 3% saving is 900 liters (~$1,000). The clutch also reduces fan noise at highway speeds by up to 8 dB(A), improving operator comfort and reducing fatigue.
Predictive maintenance: During daily inspections, listen for fan noise. If the fan roars loudly immediately after a cold start, the clutch may be stuck engaged. If you see silicone oil residue on the fan blades or shroud, the clutch has leaked. Replace it before it fails completely. Also, monitor coolant temperature – if it consistently runs too cold (<80°C), the clutch may be stuck engaged; if it runs too hot (>110°C), the clutch may be stuck disengaged.
Payback analysis: A genuine XCMG 800172875 viscous clutch costs approximately $180. If it saves 900 liters of fuel per year ($1,000), the ROI is less than 3 months. Additionally, it reduces wear on the water pump bearing and fan belt, extending their lives by thousands of hours.
Every XCMG Viscous Clutch 800172875 is manufactured in an IATF 16949‑certified facility. Each unit undergoes 100% functional testing: engagement temperature (measured by thermocouple), torque output at full engagement, and leak testing (helium mass spectrometry). Random samples are subjected to high‑temperature endurance (1,000 hours at 120°C), vibration testing, and 500‑hour salt spray. XCMG provides a 24‑month warranty against fluid leaks, bearing failure, or valve malfunction.
Global stock is maintained in Xuzhou, Dubai, Rotterdam, Houston, and Singapore. Emergency orders ship within 24 hours. Bulk packs of 5 clutches (part number 800172875‑B5) are available for fleet customers at a 12% discount. Each clutch includes a new mounting nut, lock washer, and a small tube of thread‑locking compound for the fan bolts.
To verify authenticity, scan the QR code on the packaging – it links to the test certificate showing engagement temperature, torque curve, and bearing noise measurement. Always insist on genuine XCMG 800172875; counterfeit clutches have been known to seize or explode, causing fan blade shrapnel and severe engine damage.
XCMG engineers tested the 800172875 viscous clutch under extreme conditions: 8,000 hours of continuous operation in a lab dynamometer simulating mining haul cycles, -45°C cold starts, +55°C desert ambient, and high‑dust environments. The clutch maintained correct engagement temperature within ±3°C, and the silicone fluid showed no viscosity degradation. The bearing retained its original clearance after 10,000 hours of testing.
For extremely dusty environments (e.g., coal mines), XCMG recommends adding a pre‑filter screen over the bimetal coil to prevent debris from jamming the valve. This accessory (part number 800172875‑FILT) is available separately and extends clutch life by up to 40% in severe dust.
The clutch housing is E‑coated and has passed 1,000 hours of salt spray testing, ensuring corrosion resistance even in coastal mining operations. The aluminum alloy is also resistant to galvanic corrosion when mounted on a steel water pump hub.
