The WEICHAI WP12 Oil Pump Assembly is the heart of the lubrication system for WP12 series heavy-duty diesel engines. This precision-engineered pump ensures consistent oil pressure across all operating ranges, protecting bearings, camshafts, and turbochargers from metal-to-metal contact. When you source genuine WEICHAI Engine Parts, you receive a complete assembly that includes the pump housing, internal gears, pressure relief valve, and drive gear – all pre-calibrated for the WP12 engine. The WEICHAI WP12 Oil Pump Assembly delivers a flow rate of 280 L/min at rated speed and maintains oil pressure between 4.5 and 5.5 bar under normal conditions, effectively lubricating critical components even at low idle.
The WEICHAI WP12 Oil Pump Assembly is a positive displacement gear-type pump designed to supply pressurized engine oil to all moving parts within the WP12 diesel engine. It mounts directly to the front timing gear housing and is driven by the crankshaft gear, ensuring instantaneous oil flow upon engine startup. The assembly comprises a cast aluminum housing, two hardened steel gears (drive and driven), a pressure relief valve, and an integrated pickup tube. Every unit is machined to tight tolerances of 0.02mm on gear end clearance to minimize internal leakage and maximize volumetric efficiency.
Unlike generic replacement pumps, the genuine WP12 oil pump features a dual-stage relief valve system that maintains stable pressure across a wide RPM range. The primary relief valve opens at 7.5 bar to protect the oil filter and cooler from overpressure, while the secondary valve bypasses the cooler during cold starts to accelerate warm-up. This intelligent design prevents oil starvation during high-demand conditions such as climbing grades or towing heavy loads. The pump also incorporates a pressure tapping port for easy diagnostic connection.
The gear teeth are precision hobbed from case-hardened alloy steel (20CrMnTi) and finished with isotropic superfinishing to reduce friction and noise. Independent tests show that the WEICHAI WP12 Oil Pump Assembly operates at 72% mechanical efficiency, which is 5–8% higher than many aftermarket alternatives. The housing includes reinforced mounting bosses and a rubber-coated gasket to eliminate oil seepage. With a service life exceeding 800,000 km under normal maintenance, this pump is built for long-haul reliability.
Every WEICHAI WP12 Oil Pump Assembly is 100% flow-tested on a dedicated test bench before leaving the factory. The test report records flow rate at three different speeds (800, 1800, and 2400 rpm) as well as relief valve cracking pressure. Each pump is laser-engraved with a unique serial number, allowing users to verify authenticity and access production data online. This level of quality control ensures that your engine receives the exact lubrication performance specified by Weichai Power.
Product Parameters of WEICHAI WP12 Oil Pump Assembly
NO.
Part NO.
Description
1
612630270531
Oil Pump Housing (Die-cast Aluminum)
2
612630280545
Drive Gear (20CrMnTi, 12 Teeth)
3
612630290562
Driven Gear (20CrMnTi, 12 Teeth)
4
612630300578
Pressure Relief Valve Assembly (7.5 bar)
5
612630310592
Secondary Bypass Valve (Cold Start)
6
612630320605
Oil Pickup Tube With Strainer
7
612630330619
Housing Gasket (Viton-coated)
8
612630340622
Mounting Bolt Set (M8x35mm, Grade 10.9)
9
612630350637
Pressure Port Plug (M12x1.5)
10
612630360641
Drive Shaft Seal (PTFE)
11
612630370658
Complete Assembly (Pre-lubricated)
12
612630380663
Identification Tag (QR Code)
Why Choose Our WEICHAI WP12 Oil Pump Assembly?
Our WEICHAI WP12 Oil Pump Assembly is manufactured in ISO 14001-certified facilities using original tooling and materials approved by Weichai Power. Each pump undergoes a rigorous 12-step quality process including gear profile measurement, housing porosity testing, and assembly run-in. We guarantee that every pump meets or exceeds OE specifications for flow rate, pressure stability, and noise emission. With over 15,000 units sold globally, our oil pumps have proven their reliability in harsh environments from Australian mine sites to Siberian logging operations.
We offer a complete drop-in solution: the assembly arrives with all gaskets, O-rings, and bolts pre-packaged. No additional parts hunting or modifications are required. The pump’s mounting flange and gear mesh alignment are pre-set to eliminate timing issues. Additionally, our technical team provides free access to installation torque sequences and troubleshooting guides via QR code on the product label. This saves workshops an average of 45 minutes per installation compared to piecing together components from different suppliers.
Unlike many aftermarket pumps that use inferior cast iron housings or unhardened gears, our assembly maintains the original aluminum housing for weight savings and heat dissipation. The gears are vacuum-carburized to a depth of 0.6–0.8mm and then tempered, achieving a surface hardness of 58–62 HRC. We also apply a manganese phosphate coating on all ferrous parts to resist rust during storage and initial operation. A 24-month unlimited-mileage warranty backs every WEICHAI WP12 Oil Pump Assembly, covering material defects and premature wear.
Cost efficiency is another key advantage. By sourcing directly from the contract manufacturer who supplies Weichai’s assembly line, we eliminate middleman markups while maintaining identical quality. Our price is typically 35% lower than dealer list price. Bulk discounts are available for fleet operators ordering 10+ units. Moreover, our regional warehouses in Dubai, Houston, and Shanghai ensure 48-hour delivery to most industrial zones. Choose our assembly for unmatched value, traceability, and peace of mind.
What are the Routine Maintenance Considerations for the WEICHAI WP12 Oil Pump Assembly?
Inspect the oil pump drive gear for wear every 200,000 km or during any major engine overhaul. Excessive backlash or chipped teeth indicate timing gear train issues that must be addressed before they damage the pump. Always replace the pump if the housing shows cracks or scoring on the gear pocket surfaces. Use a dial gauge to measure end clearance between gears and housing; the service limit is 0.15mm. Beyond this, volumetric efficiency drops significantly, risking low oil pressure at idle.
When changing engine oil, always clean the pump’s pickup tube strainer if accessible. Debris such as gasket sealant or carbon flakes can partially block the strainer, causing cavitation and pressure fluctuation. Never use compressed air to blow through the pump assembly without disassembly, as this can damage the relief valve seat. If the engine experiences a sudden loss of oil pressure, do not simply replace the pump – also inspect the oil filter bypass valve, cooler, and main bearing clearances to identify root cause.
Use only the recommended oil viscosity (15W-40 or 10W-30, API CK-4) as specified for the WP12 engine. Excessively thick oil during cold weather can overstress the pump drive and cause the relief valve to stick. Conversely, oil that is too thin may lead to internal leakage and reduced pressure. During oil changes, inspect the old oil filter for metal particles; fine metallic dust suggests gear wear inside the oil pump. In such cases, replace the pump and thoroughly flush the lubrication system.
If you store a spare WEICHAI WP12 Oil Pump Assembly, keep it in a clean, dry environment between -20°C and 50°C. Rotate the drive gear manually every six months to redistribute internal lubricant. Before installation, prime the pump by filling the inlet port with clean engine oil to ensure immediate suction on first start. Failure to prime can cause dry running and permanent damage within seconds. Following these maintenance guidelines will maximize pump lifespan and protect your engine investment for years to come.
If you have any questions about our products, services, or anything related to what we offer, please don’t hesitate to leave us a message—our dedicated team is always ready to provide prompt and helpful responses to address your concerns. What’s more, when you become our valued customer, we’re delighted to offer you complimentary catalog services, giving you access to detailed, up-to-date information on our full range of products, specifications, and offerings to help you make informed decisions.
