The New Japan Yanmar 123010-42500 is a complete, genuine replacement impeller pump and vacuum pump assembly designed specifically for Yanmar agricultural and compact tractors. This critical component serves a dual purpose: it circulates coolant to maintain optimal engine temperature and generates vacuum for the power-assisted brake system.
If your tractor is experiencing engine overheating or a loss of brake assist, this unit is the direct OEM replacement to restore reliable performance and protect your engine from costly damage.
Key Features & Benefits
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OEM Genuine Part: Manufactured by Japan Yanmar, ensuring perfect fit, form, and function. Guaranteed compatibility and reliability.
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Complete Assembly: This is not just the impeller. The unit comes as a full assembly, including the housing, impeller, and mechanical seal, making installation quick and straightforward.
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Dual-Function Design: Combines the essential coolant water pump and vacuum pump into a single, compact unit, saving space and simplifying the engine system.
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Precision Engineering: Features a durable, wear-resistant impeller and a high-quality mechanical seal to prevent coolant leaks and ensure long service life.
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1-Inch Inlet/Outlet: Designed with standard 1-inch ports for easy connection to your tractor’s cooling system hoses.
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Prevents Engine Damage: A faulty water pump is a leading cause of engine overheating. Replacing it with this genuine part ensures efficient heat dissipation and prevents severe engine damage.
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Restores Brake Power: A functioning vacuum pump is crucial for the power brake system. This unit ensures you have safe, responsive braking.
Technical Specifications
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Part Number: 123010-42500
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Replaces/Old Number: 123010-42501
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Type: Coolant Impeller Pump & Vacuum Pump Assembly
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Port Size: 1 Inch (approx. 25.4 mm)
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Manufacturer: Japan Yanmar (Genuine/OEM)
Common Yanmar Tractor Models This Part Fits:
This pump is compatible with a wide range of popular Yanmar tractor models, including but not limited to:
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Yanmar YM Series: YM165, YM165D, YM169, YM169D, YM186, YM186D, YM226, YM226D, YM231, YM231D, YM240, YM240D, YM242, YM242D, YM276, YM276D, YM330, YM330D
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Yanmar FX Series: FX165, FX165D, FX18, FX18D, FX22, FX22D, FX24, FX24D, FX26, FX26D, FX32, FX32D
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Yanmar F Series: F16, F16D, F18, F18D, F20, F20D
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And Many More: Also fits certain models of the YM155, YM195, YM195D, and others. Always cross-reference your tractor’s model number to confirm compatibility.
Symptoms of a Failing Pump:
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Engine overheating or running hotter than normal.
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Coolant leakage from the pump housing or seal.
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Grinding or whining noise coming from the pump area.
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Loss of power brake assist, making the brake pedal hard to press.
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Visible wobble or play in the pump pulley.

























