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The WEICHAI WP12 Engine Oil Cooler Cover Assembly is a precision-machined, high-strength cast aluminum component that seals and secures the engine oil cooler core against the engine block in WP12 heavy-duty diesel engines. As a critical part of the lubrication and cooling system, the WEICHAI WP12 Engine Oil Cooler Cover Assembly incorporates integrated flow channels for both engine oil and coolant, enabling efficient heat exchange to maintain optimal oil viscosity and prevent thermal degradation. For genuine replacement parts, always choose verified WEICHAI Engine Parts to guarantee perfect fitment, reliable sealing, and long-term durability across all WP12 engine variants from 336 HP to 550 HP.
The WEICHAI WP12 Engine Oil Cooler Cover Assembly is a robust cast aluminum housing that serves as the outer casing and sealing mechanism for the engine oil cooler core. Positioned on the engine block, typically on the left side below the exhaust manifold, this cover assembly firmly clamps the oil cooler core against the engine block using multiple high-strength bolts. The cover incorporates integrated oil intake and outlet passages as well as dedicated coolant circulation channels, allowing high-temperature engine oil (which can exceed 120°C under peak load) and engine coolant to flow efficiently in a counter-flow or cross-flow configuration within the cooler core. This design maximizes heat transfer efficiency, rapidly dissipating excess heat from the oil to maintain optimal operating temperature.
The WEICHAI WP12 Engine Oil Cooler Cover Assembly is manufactured from high-quality cast aluminum alloy, offering an excellent balance of strength, lightweight construction, and corrosion resistance. The cast aluminum construction weighs only 2.5 kg while providing the rigidity needed to withstand high-pressure oil and coolant flow, as well as the thermal cycling stresses from repeated heating and cooling. The cover’s integrated channels are precision-machined to ensure low flow resistance, allowing the engine oil and coolant to circulate freely through the cooler core without pressure drop. The cover also includes precision-machined sealing surfaces that accept high-quality O-rings and gaskets (such as O-ring Part No. 612630010107), creating a leak-free seal that prevents the intermixing of engine oil and coolant — a condition that would otherwise lead to severe engine damage through sludge formation and bearing failure.
The WEICHAI WP12 Engine Oil Cooler Cover Assembly performs three critical functions: sealing and securing the oil cooler core, routing oil and coolant flow, and protecting the engine lubrication system. First, the cover uses multiple mounting bolts to securely compress the oil cooler core against the engine block, preventing any movement or vibration damage. Second, the integrated flow channels direct high-temperature oil into the cooler core and then return cooled oil to the engine’s lubrication system, while simultaneously routing coolant through the core to absorb heat. Third, by maintaining the oil at its optimal temperature range (typically 80-105°C), the cover assembly ensures that the oil retains its proper viscosity and lubricating properties, protecting critical components such as main bearings, connecting rod bearings, the crankshaft, and the turbocharger from accelerated wear. The cover assembly effectively combines the functions of an outer casing, fluid passages, and sealing mechanism into one integrated unit, ensuring reliable, leak-free system operation.
Applications for the WEICHAI WP12 Engine Oil Cooler Cover Assembly include Shacman X3000/F3000/X5000 series trucks, Sinotruk HOWO A7, Dongfeng KL heavy-duty vehicles, SDLG wheel loaders, XCMG excavators and cranes, Liugong bulldozers, marine propulsion systems (WP12C series with SAE-I flywheel configuration), and stationary generator sets. This cover assembly is compatible with WP12 engine power outputs ranging from 336 HP to 550 HP across Euro III, Euro IV, Euro V, and China VI emission standards. Multiple OEM part numbers exist depending on application and engine variant: common OE references include 612630010072 (Euro III, WP12 truck applications), 1003285150 (WP12/WP13 engine variant), 612600012437, and 1003712818 (WP12NG natural gas engine variant). The marine variant of the WP12 engine is assembled with a corresponding SAE-I configuration oil cooler cover. Each genuine WEICHAI WP12 Engine Oil Cooler Cover Assembly carries cast-in or etched part numbers and production date codes for full traceability. Counterfeit covers often use inferior cast aluminum with porosity defects, leading to coolant or oil leakage, improper sealing, and premature failure. Always source from authorized distributors to ensure the cover assembly meets WEICHAI’s original engineering drawings, material specifications, and dimensional tolerances.
| NO. | Part NO | Description |
|---|---|---|
| 1 | 612630010072 | Complete Oil Cooler Cover Assembly (Euro III, WP12 270-480 HP) |
| 2 | 1003285150 | Oil Cooler Cover Assembly (WP12/WP13 Engine, 2.5kg, 45x35x8cm) |
| 3 | 612600012437 | Oil Cooler Cover Assembly (Universal WP12/WD12 Variant) |
| 4 | 1003712818 | Oil Cooler Cover Assembly (WP12NG350E52 Natural Gas Engine) |
| 5 | 612630010107 | Oil Cooler Cover O-Ring / Seal (Gasket Replacement) |
| 6 | 612600130053 | Oil Cooler Cover Bolt Set (Grade 10.9, with Washers) |
| 7 | 612630010050 | Engine Oil Cooler Assembly (Complete with Cover and Core) |
| 8 | 612600150106 | Gasket / Sealing Ring for Oil Cooler Cover |
| 9 | 1441211-00042-001 | Oil Cooler Cover Assembly (OEM Equivalent to 612600012437) |
| 10 | 1448111-00004-001 | Oil Cooler Cover Bolt (Replacement Bolt for WP12) |
The table above lists the most commonly ordered service parts for the WEICHAI WP12 Engine Oil Cooler Cover Assembly. When replacing the cover assembly (Part No. 612630010072 or 1003285150), always install new sealing components including O-rings (Part No. 612630010107) and gaskets (Part No. 612600150106) to ensure a leak-proof seal. The cover is manufactured from high-strength cast aluminum with a weight of approximately 2.5 kg and overall dimensions of 45 × 35 × 8 cm. Cover bolts (Part No. 612600130053) are grade 10.9 torque-to-yield fasteners that must be replaced with new units—never reuse old cover bolts. The complete oil cooler assembly (Part No. 612630010050) is available for applications requiring both the cooler core and cover.
Our WEICHAI WP12 Engine Oil Cooler Cover Assembly is manufactured from premium-grade cast aluminum alloy, offering an excellent strength-to-weight ratio and superior corrosion resistance. The lightweight design (only 2.5 kg) reduces overall engine weight while providing the structural rigidity needed to withstand high-pressure oil flow (up to 550 kPa / 80 psi) and continuous thermal cycling from -35°C to 120°C.
Precision-machined integrated flow channels are engineered for minimal flow resistance, ensuring that high-temperature engine oil and coolant circulate efficiently through the cooler core. The optimized channel geometry provides a balanced pressure drop across the system, maintaining proper flow rates even at peak engine loads (2,300 N·m torque) and high RPM operation.
High-precision machined sealing surfaces, combined with genuine WEICHAI O-rings and gaskets, provide exceptional sealing performance that effectively prevents oil-coolant cross-contamination—a condition that would otherwise cause catastrophic engine damage through sludge formation and bearing failure. The sealing system is tested to withstand over 1,000 thermal cycles without degradation.
No modifications required for WP12 engines in Shacman (X3000/F3000/X5000), Sinotruk HOWO, Dongfeng, SDLG, XCMG, marine vessels, and generator sets. Bolt-on replacement with factory-specified torque values (cover bolts: 25-30 N·m, symmetrical cross-tightening sequence). Available for Euro III, Euro IV/V, China VI, and natural gas engine variants.
Each WEICHAI WP12 Engine Oil Cooler Cover Assembly undergoes rigorous quality control including dimensional inspection (bolt hole locations ±0.10mm, sealing surface flatness), pressure leak testing at 5 bar, material verification (cast aluminum grade), and surface finish inspection. No porosity, casting defects, or machining errors are tolerated.
We ship worldwide from regional warehouses. Free oil cooler cover installation torque charts (cover bolts: 25-30 N·m, cross-tightening sequence), seal replacement procedures, and troubleshooting guides provided with each order. Volume discounts available for fleet customers and engine rebuilders. Over 500 workshops worldwide trust our genuine-spec oil cooler cover components.
Unlike low-cost alternatives that use inferior cast aluminum with porosity defects and inconsistent heat treatment, our WEICHAI WP12 Engine Oil Cooler Cover Assembly is manufactured from certified aluminum alloy with documented material certificates and full traceability. Independent laboratory testing confirms that our cover assembly withstands over 10,000 thermal cycles from -30°C to 120°C without cracking or distortion, far exceeding the service life requirements of the WP12’s B10 overhaul interval of 1,800,000 km. The cover is also phosphate-coated for additional corrosion resistance, protecting against oxidation in marine environments and high-humidity operating conditions.
Each cover assembly is cast using precision die-casting techniques with computer-controlled pouring temperatures to eliminate porosity and cold shut defects. After casting, the cover undergoes a multi-stage surface finishing process including deburring, shot blasting, and precision CNC machining of all critical surfaces including sealing faces, bolt holes, and flow channels. The bolt hole threads are rolled (not cut) to provide superior thread strength and fatigue resistance compared to cut threads. The sealing surfaces are machined to a surface finish of RA 1.6 μm, ensuring an optimal mating surface for the O-ring and gasket to create a leak-free seal.
Technical support is available via email with complete oil cooler cover installation procedures: clean both mating surfaces thoroughly, install new O-rings and gaskets (Part No. 612630010107 and 612600150106), lubricate bolt threads with clean engine oil, torque the cover bolts to 25-30 N·m using a symmetrical cross-tightening sequence (working outward from the center), and verify no leaks by running the engine at idle and checking for oil or coolant seepage. We also provide troubleshooting guides for symptoms like milky oil (coolant contamination from failed seal), oil leaks from the cover area (worn O-ring or cracked cover), and overheating (blocked flow passages or insufficient cooler core contact). Our goal is to make your WP12 engine lubrication system restoration straightforward and cost-effective.
For large fleets, we offer sample testing: order one WEICHAI WP12 Engine Oil Cooler Cover Assembly first for trial installation on one engine. If satisfied, volume pricing applies. Many return customers report over 800,000 km of trouble-free lubrication system operation after replacing cracked or warped original covers with our genuine-spec components. We also stock both Euro III cover assemblies (612630010072) and Euro IV/V/China VI covers (1003285150) to cover all WP12 engine vintages, as well as natural gas engine variants (1003712818), and we provide cross-reference support for part number verification based on your engine serial number.
Beyond the checklist above, pay attention to engine starting behavior and warm-up characteristics. If the engine takes longer than normal to build oil pressure after cold start, the WEICHAI WP12 Engine Oil Cooler Cover Assembly may have a cracked sealing surface allowing oil to drain back to the pan when the engine is off. A slow pressure buildup indicates air in the lubrication system, which can be caused by a failed cover seal that allows oil to bypass the oil pump pickup. If the engine produces excessive white smoke on start-up, this may indicate coolant entering the combustion chamber through a cracked cover — perform a cooling system pressure test (pressurize to 1.2 bar and watch for pressure drop) to confirm cover integrity.
For vehicles operating in extreme environments (mining, construction, high-dust, marine saltwater), the WEICHAI WP12 Engine Oil Cooler Cover Assembly may be subjected to accelerated corrosion. Reduce the inspection interval to every 25,000 km (15,000 miles) or 250 operating hours in severe-duty applications. Consider applying a corrosion inhibitor coating to the exterior of the cover to protect against saltwater exposure in marine applications. For engines operating in freezing conditions, ensure that the coolant contains sufficient antifreeze concentration (40-60% ethylene glycol) to prevent freeze damage — ice expansion inside the cover’s coolant passages can crack the casting, leading to internal leaks that may not be immediately visible externally.
If the engine experiences a cooling system overpressure event (such as from a blown head gasket pressurizing the coolant system), the WEICHAI WP12 Engine Oil Cooler Cover Assembly must be inspected for internal cracks even if no external damage is visible. Overpressure can cause the cover to crack internally around the oil and coolant passages, creating cross-contamination pathways that are not visible from the exterior. A pressure test of the cover assembly (using a pressure tester to 5 bar) is required to verify integrity after any significant overpressure event.
Finally, maintain a logbook of all maintenance actions: dates, cover bolt torque verification readings, seal replacement intervals, oil temperature trends, coolant consumption rates, and any abnormal findings. This historical data helps predict when the WEICHAI WP12 Engine Oil Cooler Cover Assembly might need replacement based on actual operating conditions rather than arbitrary mileage intervals. For fleet operators, tracking oil analysis results (specifically coolant trace elements like sodium or potassium) is a powerful predictive maintenance tool — elevated coolant metals in used oil analysis indicates cover seal failure or internal cover cracking well before visible symptoms appear, providing a critical warning window for proactive replacement.
In summary, the WEICHAI WP12 Engine Oil Cooler Cover Assembly stands out for its high-strength cast aluminum construction, precision-machined flow channels, and superior sealing reliability. Whether you are rebuilding a Shacman X3000, Sinotruk HOWO, SDLG wheel loader, marine vessel, or generator set, choosing a quality oil cooler cover assembly directly impacts oil temperature control, engine lubrication quality, and overall vehicle reliability. Always verify the part numbers against your engine serial number before ordering — Euro III mechanical pump engines use the 612630010072 cover assembly, Euro IV/V/China VI common rail engines use the 1003285150 cover assembly, and natural gas engines use the 1003712818 cover assembly.
For workshops performing in-frame overhauls, we recommend ordering the WEICHAI WP12 Engine Oil Cooler Cover Assembly together with a complete lubrication system service kit that includes new O-rings (Part No. 612630010107), gaskets (Part No. 612600150106), cover bolts (Part No. 612600130053), and a new oil cooler core (Part No. 612630010050). This approach eliminates hidden failures and gives your customer a worry-free warranty period. The oil cooler cover assembly is pre-inspected for flatness (0.05mm maximum), thread integrity, and casting soundness before shipment.
Our inventory includes both standard oil cooler cover assemblies for highway truck applications and heavy-duty variants for off-highway and severe-duty applications. The standard WEICHAI WP12 Engine Oil Cooler Cover Assembly provides excellent service life for long-haul trucking, while the heavy-duty variant features additional ribbing and thicker wall sections for mining, construction, and marine applications. Select accordingly based on your application and operating environment. We also provide cross-reference support for part number verification — please provide your engine serial number for accurate matching.
We also provide after-sales documentation including dimensional inspection reports (bolt hole locations, sealing surface flatness, flow channel dimensions), material certificates (chemical composition and mechanical properties of cast aluminum), and pressure test results (leak testing at 5 bar) upon request. Every WEICHAI WP12 Engine Oil Cooler Cover Assembly is packaged in anti-corrosion oil and foam-lined boxes to prevent damage during shipping. Bulk orders receive custom palletizing and export documentation assistance. Express shipping available for urgent repairs — most orders dispatched within 24 hours.
All specifications are based on original WEICHAI WP12 engine technical data. Actual product dimensions may vary by sub-model (E3, E5, China VI, marine, natural gas, etc.). Always cross-check part numbers with your engine’s serial number plate. The WEICHAI WP12 Engine Oil Cooler Cover Assembly is a direct replacement for original equipment part numbers 612630010072 (Euro III), 1003285150 (Euro IV/V/China VI), 612600012437, and 1003712818 (natural gas). Always replace O-rings and gaskets, use new cover bolts, and torque to 25-30 N·m in a symmetrical cross-tightening sequence during installation.
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