Nissan 21010-31U25 Pump Assembly

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Checking the water pump's functionality is crucial, as its failure can lead to severe engine damage from overheating. Two methods can be employed to assess the water pump while it remains installed on the engine, and if any defects are identified, it should be replaced with a new or rebuilt unit. Water pumps come equipped with weep (vent) holes, with SOHC engines featuring a weep hole on the pump's underside. To inspect for leaks, the timing belt cover can be removed on SOHC engines, allowing the use of a flashlight and small mirror to locate the hole from underneath. On DOHC engines, the weep hole directs coolant outward between the timing chain cover and the engine block. In cases of water pump shaft bearing failure, a howling sound may be noticeable while the pump is running. SOHC engines may exhibit shaft wear when the drivebelt is removed, and the water pump pulley is rocked up and down with the engine off. On DOHC engines, shaft wear can be detected by relieving the main timing chain tension and removing the water pump access cover, enabling the rocking of the water pump sprocket to detect shaft wear. It's important not to confuse drivebelt slippage, which causes a squealing sound, with water pump bearing failure. Replacement involves disconnecting the battery's negative terminal, draining the cooling system, and removing drivebelts. On SOHC engines, the water pump pulley is immobilized with a strap wrench, and the pulley is removed along with the crankshaft pulley and timing belt covers. On DOHC engines, the idler pulley bracket and right-side engine mount and brackets are removed, along with the main timing chain tensioner cover and water pump cover. Bolts are then removed to detach the water pump, and the impeller on the backside is inspected for corrosion or missing fins. After cleaning the bolt threads and threaded holes, the new pump is compared to the old one to ensure they match. Any remnants of old gasket sealant are removed from the engine, and the engine and new water pump mating surfaces are cleaned with lacquer thinner or acetone. On SOHC engines, a thin layer of ATV sealant is applied to the new pump, and a new gasket is set in place. On DOHC engines, new O-rings are installed on the pump, and a light coat of grease is applied to the O-rings for easier installation into the engine block. The pump is then carefully attached to the engine, and bolts are threaded in finger-tight, using a small amount of ATV sealant on the bolt threads. Caution is exercised not to overtighten the bolts to prevent pump distortion. On DOHC engines, the crankshaft is rotated 20 degrees clockwise to tighten the timing chain around the water pump sprocket. After removing the stopper pin from the timing chain tensioner, the tensioner cover and water pump access cover are installed after being cleaned and treated with ATV sealant. All parts removed for access to the pump are reinstalled, the cooling system is refilled and bled, and drivebelt tension is checked. The engine is run, and any leaks are monitored. It's worth noting that timing chain noise may briefly occur on DOHC engines after this procedure, which is normal and should subside once air has been bled from the high-pressure chamber by running the engine at 3,000 rpm in Neutral or Park until the noise dissipates.

According to the VIN, The water pump does not come with the O-rings. You would need to order both O-Rings and the water pump.