350-04014-0 Nissan CHECK VALVE

Illustration 1 g00927439
(1) Jacket water pump (2) Jacket water heater (3) Engine oil cooler (4) Cylinder liners (5) Cylinder heads (6) Expansion tank (7) Water temperature regulator (8) Aftercooler (9) Turbocharger (10) Turbocharger (12) Cylinder heads (11) Cylinder liners (13) Cylinder block (14) Orifice plate (15) Generator oil cooler (16) Jacket water heater (17) Heat exchangerThe engine is cooled by the engine jacket water system. The jacket water is circulated by the jacket water pump that is driven by the engine. The jacket water pump is mounted off the front of the lower right accessory drive. The jacket water pump receives jacket water from the expansion tank. The engine jacket water is a 50/50 mix of distilled water and propylene glycol with a conditioner added for prevention of mineral deposits and corrosion. The jacket water exits the pump through an elbow and the jacket water is divided.Part of the jacket water flows to the aftercooler while the remainder flows to the engine oil cooler. The jacket water flows through the aftercooler. The jacket water flows through the engine oil cooler. Both flows then enter the cylinder block.The jacket water then enters the water jackets and flows around the cylinder liners. The jacket water flows from the bottom to the top of each cylinder liner. The jacket water then flows through each cylinder head. The jacket water exits to a water manifold which delivers the cooling water to the lower housing of the temperature regulator.There are four water temperature regulators (thermostats) that are mounted in the regulator housing. The temperature sensing bulb of each water temperature regulator is mounted in the upper regulator housing. When the water temperature regulators are closed, the full flow of the jacket water exits the engine and flows to the upper regulator housing. The jacket water will pass across the sensing bulbs of the water temperature regulator and the jacket water is bypassed directly to the expansion tank for the engine. As the water temperature regulators start to open, an amount of the flow of the jacket water is diverted from the lower regulator housing to a heat exchanger that is customer supplied that is not mounted to the engine. The jacket water that is diverted to the heat exchanger returns into the engine at the upper regulator housing. The jacket water from the heat exchanger mixes with the jacket water that was not sent through the heat exchanger and flows to the expansion tank. Inlet regulated systems are designed to provide a consistent temperature to the inlet of the jacket water, aftercooler, and oil cooler. This is accomplished by placing the sensing bulbs of the water temperature regulators in the inlet flow to the engine. The water temperature regulator then balances the bypass flow with the cooled jacket water from the heat exchanger.Generator
Jacket water is also used to cool the lubrication oil for the generator. As the jacket water exits the heat exchanger, a small portion of the flow is diverted before returning to the engine's upper regulator housing. The diverted jacket water is sent through the generator oil cooler.After cooling the lubrication oil for the generator, the diverted jacket water returns to the expansion tank for the engine. In the expansion tank, the diverted jacket water mixes with the remainder of the jacket water before returning to the suction side of the jacket water pump. No separate pump is necessary for this circuit.When the temperature regulators are closed, the resistance that is provided by the regulator housing and the expansion tank pressure cap ensure sufficient flow through the generator oil cooler. When the water temperature regulators are open, there is flow from the engine to the heat exchanger.An orifice in the return line for the jacket water to the engine provides flow to the generator oil cooler. The system is designed to provide lubrication oil to the generator bearings. The cooling system for the generator maintains a temperature of 50 to 55 °C (122 to 131 °F). This is sufficient to maintain the temperature of the oil film for the generator bearing within allowable limits.