Forklift Water Pump — Xichai 4DW91 Engine Cooling Water Pump for Hyster Forklift Trucks

This forklift water pump is a Kingstream OEM engine cooling water pump for the Xichai 4DW91 diesel engine used in Hyster forklift trucks across hotels, garment, building material, manufacturing, construction, port, warehousing, logistics, mining, and agricultural environments. The 4DW91 is a 4-cylinder diesel engine commonly deployed in Hyster 2-3.5 ton forklift models — a workhorse engine platform in global material handling. The water pump is a belt-driven centrifugal pump that circulates coolant through the engine block and cylinder head water jackets, transferring combustion heat to the radiator for dissipation. A properly functioning water pump maintains engine temperature between 82-95°C under load — the optimal range for diesel combustion efficiency and engine longevity. 10kg weight with 50×50×30cm packaging options in carton box or wooden box. 100% professional tested with 7-15 day delivery. Kingstream OEM available for Hyster forklift fleet operators.

Diagnosing a failing water pump on a 4DW91 engine involves three progressive symptoms. First: a small coolant drip from the weep hole at the bottom of the pump housing — this is the designed leak path for coolant that has migrated past the internal shaft seal, and it indicates the seal has worn. This drip typically starts intermittently (only after engine shutdown when the system is still pressurized and cooling) and progresses to a constant leak. Second: a grinding, rumbling, or squealing noise from the water pump area — this indicates the pump shaft bearing is worn, allowing the shaft to wobble. A wobbling shaft accelerates seal failure and can cause the fan belt to be thrown off if the pulley misalignment becomes severe. Third: engine overheating despite a full radiator and functional thermostat — the pump impeller may be slipping on the shaft (pressed-on impellers can spin on a worn shaft without visible external leakage), or the impeller vanes may be eroded from cavitation damage after years of operation with incorrect coolant mixture. Installing the replacement pump requires draining the coolant, removing the fan belt, unbolting the old pump from the engine block, thoroughly cleaning the mounting surface of old gasket material, installing a new gasket, and torquing the mounting bolts in a cross pattern to specification. Refill with the correct 50/50 coolant-distilled water mixture after installation and bleed trapped air from the cooling system. Run the engine until the thermostat opens and verify no leaks at the pump mounting surface or hose connections.

Browse our complete Forklift Water Pump category for additional engine water pumps including 490B-42100 for 490/498 engines, C240-8-94376-86 for C240 engines, 4D35ZG31-42100, Yunnei 4100/490, and Xichai 6110 water pumps. For Hyster forklift fleet cooling system maintenance programs, contact us.

Technical Specifications

100% professional tested. Carton box or wooden box packaging. Kingstream OEM. For bulk orders, contact us.