1727765 Water Pump Fits Caterpillar ModelsOne New Aftermarket Replacement Water Pump for Caterpillar (Cat) 3306 3306B Engines This engine cooling water pump is a direct aftermarket replacement for the Caterpillar (Cat) 3306 and 3306B diesel engine, serving the engine cooling system across a wide range of Cat construction, earthmoving, and agricultural equipment. The pump circulates coolant through the engine block to maintain safe operating temperatures under heavy duty working conditions.