A precision-engineered engine oil bypass valve (oil filter relief valve) that maintains continuous oil flow to critical engine components when the oil filter becomes restricted, preventing oil starvation and engine damage in ISUZU NKR diesel engines.

The Bypass Valve Assembly (OEM Numbers: 8-97013566-0 / 8970135660) is a premium-quality, direct replacement engine lubrication component engineered specifically for ISUZU NKR, NPR, NHR, and N‑Series light trucks, as well as industrial applications powered by the legendary 4JB1, 4JA1, 4JH1, 4HF1, 4HG1, and 4BD1 diesel engines.

This bypass valve (also known as an oil filter relief valve or oil cooler bypass valve) serves as a fail‑safe mechanism. Under normal operating conditions, engine oil is forced through the full‑flow oil filter, where contaminants are removed. However, if the oil filter becomes restricted (due to excessive mileage, sludge, or extremely cold, thick oil), the pressure differential across the filter increases. When this pressure reaches the calibrated threshold (typically 1.5‑2.5 bar), the bypass valve opens, allowing unfiltered oil to flow directly to the engine's main gallery and critical components – preventing oil starvation, bearing seizure, and catastrophic engine failure.

Engineered to meet or exceed original equipment (OE) specifications, this bypass valve is precision‑machined from high‑strength, heat‑treated steel or corrosion‑resistant alloy, featuring a precision‑ground plunger, calibrated spring, and high‑temperature sealing elements.

• OE Quality: Manufactured to strict ISUZU OEM dimensional and material standards for a perfect, direct‑fit replacement
• Critical Engine Protection Component: The engine's last line of defence against oil starvation
• Factory‑Calibrated Spring: Precision‑wound and tested to open at exact pressure required for ISUZU 4J and 4H engine families
• Corrosion‑Resistant Construction: High‑strength, heat‑treated alloy steel with corrosion‑resistant coating
• Direct Replacement for N‑Series Trucks: Fits ISUZU NKR, NHR, NPR, 100P, and ELF chassis
• ISO 9001:2015 / IATF 16949 Certified: Manufacturing facility meets international automotive quality standards
• 12‑Month Warranty: Backed by manufacturer batch traceability and comprehensive warranty

• Material verification to JIS/SAE durability standards
• Dimensional accuracy verified with CMM equipment (±0.02 mm tolerance)
• Spring calibration testing to verify opening pressure within OE specification
• Seat seal integrity inspection for zero leakage
• Corrosion testing with 96‑hour salt spray resistance
• IATF 16949 / ISO 9001:2015 certified manufacturing
• 100% visual inspection for defects and imperfections
• Anti‑corrosion packaging with VCI moisture-barrier bags
• Full documentation with certificate of conformance

• Individual Packaging: Anti‑corrosion oil‑coated, VCI moisture-barrier bags with OE-style labeling
• Wholesale/Bulk Orders: Available in case packs (10, 20, 50, 100 units) with pallet pricing
• Customization: Neutral or private-label retail packaging for volume orders
• Fast Shipping: Worldwide dispatch via express courier or economical sea freight
• Wholesale Support: Long-term supply agreements and drop-shipping options

For pricing, availability, or bulk purchase of the ISUZU Bypass Valve 8-97013566-0 (8970135660) for NKR, NHR, NPR, 100P, and compatible 4JB1, 4JA1, 4JH1, 4HF1, 4HG1 engine applications, please contact our sales team for a competitive wholesale quote and expert technical support. We respond to all inquiries within 24 hours.