Vertex Water Pump Rebuild Kit 821903 — Polaris Sportsman / Ranger 400 / 425 / 450 / 500 1995-2014

Vertex Water Pump Rebuild Kit 821903 — Polaris Sportsman / Ranger 400 / 425 / 450 / 500 1995-2014

Product Description

Keep your utility or trail machine running at peak cooling efficiency with the premium Vertex Water Pump Rebuild Kit 821903. Over years of grueling trail rides, work chores, and mud runs, factory water pump components degrade, creating high risks of coolant loss, overheating, or engine oil contamination. This heavy-duty overhaul kit provides a direct-fit solution to rebuild your mechanical water pump back to factory parameters, ensuring your engine remains structurally protected under severe thermal strain.

Every individual element within this high-grade kit is precisely manufactured to meet strict OEM specifications for dimensional tolerance and operational lifespan. Featuring high-durability mechanical seals, precision bearings, application-specific gaskets, and heavy-duty O-rings, it targets the root causes of cooling circuit pressure loss. Refreshing the entire assembly simultaneously blocks future leaks, safeguarding your hard-working four-stroke or two-stroke powerplant from devastating internal cylinder damage.

Top Features: Vertex Water Pump Rebuild Kit

• Complete Component Package: Includes every single gasket, O-ring, precision bearing, mechanical seal, snap ring, and copper washer needed for an immediate, total water pump refresh.
• Premium Mechanical Sealing Elements: Designed to withstand extreme cooling pressures and demanding heat profiles, blocking fluid transfer between water and oil chambers.
• Application-Specific Hardware: Packaged with side cover gaskets, exact-fit water pump body seals, structural snap rings, and replacement copper drain washers.
• OEM Structural Replication: Precision engineered for a drop-in installation, eliminating loose tolerances and ensuring an airtight, reliable hydrodynamic barrier.

Please review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.

Fitment List

Year Range	Vehicle Brand	Vehicle Model & Sub-Model
2013	Polaris	Ranger 500 (Mid-Size) EFI 4x4
2011-2014	Polaris	Hawkeye 400 H.O. 4x2
2011-2013	Polaris	Ranger Crew 500 (Mid-Size) EFI 4x4
2011-2012	Polaris	Sportsman Forest 500 / Forest Tractor 500
2010-2014	Polaris	Ranger 4x4 400
2008-2014	Polaris	Sportsman 400 HO
2008-2009	Polaris	Sportsman 500 EFI / EFI Touring
2006-2009	Polaris	Ranger 2x4 500 / 4x4 500 EFI
2006-2009	Polaris	Sportsman 500 EFI X2 / X2 500
2006-2007	Polaris	Sportsman 500 H.O. EFI 4x4 / Sportsman 450
2005	Polaris	Ranger 425 4x2 / ATP 500
2004	Polaris	ATP 500 H.O. 4x4
2001-2006, 2008-2013	Polaris	Sportsman 500 HO / 500 H.O. DUSE 4x4
2001-2006	Polaris	Ranger 4x4 500 / Sportsman 400
2001-2002	Polaris	Scrambler 500 2x4 / Sportsman 500 HO DUSE
2000-2008	Polaris	Sportsman 500 6x6
2000-2002	Polaris	Xpedition 425 / Sportsman 500 RSE
1999-2002	Polaris	Magnum 500 4x4
1998-2005	Polaris	Ranger 6x6 500 / Big Boss 500 6x6
1997-2012	Polaris	Scrambler 500 4x4
1996-2000	Polaris	Sportsman 500 4x4
1995-1998	Polaris	Magnum 425 4x4 / 425 2x4

Frequently Asked Questions

Q: What are the main signs that indicate a Polaris water pump mechanical seal is leaking?
A: Inspect the water pump bleed or weep hole located at the engine casing. If you spot continuous drips of anti-freeze escaping, or if your engine oil looks milky like coffee, the primary mechanical seal or oil seal has separated and requires a replacement right away.

Q: Does this kit include the internal balance shaft or water pump impeller rod?
A: No. This set consists of all the dynamic gaskets, fluid-tight O-rings, bearings, and circular snap rings required to completely rebuild the pump mechanics. Always ensure your stock drive shaft is polished clean and free of heavy structural grooves before rebuilding.

Q: Why should I always change out the copper wash gaskets when installing this kit?
A: Copper washers act as specialized crush seals. They rely on mild material compression under torque to fill microscopic machine paths. Reusing an old washer prevents it from taking a fresh seating shape, causing persistent weep drops.

Expert Pro-Tip: On older Polaris 425 and 500 motors, always ensure the water pump drive shaft area is entirely cleared of rust and scaling before putting the new mechanical seal on. Use super-fine 1000-grit emery cloth to lightly polish the shaft surface. Lubricate the inner rubber seal ring with a smear of fresh coolant or silicone grease before sliding it home to ensure the inner sealing lips do not catch, fold over, or cut on the shaft edges.

Recommended Pairings:
o 2-stroke & 4-stroke Quads / ATV Performance Parts
o Premium Motorcycle Chemicals & Engine Fluids
o MX & Off-Road Maintenance Tools

At Moto-House MX, we carry the best brands in motocross and off-road performance. Our team has over 40 years of experience helping riders get more out of their bikes. Every order ships fast from our Central Florida location.

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