CYL BLOCK PRESSURE VALVE 8973288590 8943860470 Suitable for 700P NPR models fitted with 4HK1 4HE1 4HG1 engines

Design Philosophy

Precision-engineered oil pressure relief valve designed to protect the engine lubrication system from excessive oil pressure. Made from high-strength alloy steel with precision-machined internal components, it ensures stable oil circulation and reliable engine protection under continuous operating conditions.

How It Works

Installed in the engine block lubrication circuit. When oil pressure exceeds the preset limit, the valve opens to bypass excess oil back to the sump, preventing over-pressurization that could damage seals, gaskets, and engine components. Once pressure returns to normal, the valve closes to maintain proper circulation.

Problems It Solves

Fixes excessive oil pressure, oil seal blowouts, and engine damage caused by a failed or stuck relief valve. Restores proper oil pressure regulation and protects critical engine components in 700P / NPR / NQR trucks.