Subaru 21111AA240 Water Pump Complete

Water pump failure, causing engine damage due to overheating, is indicated by coolant leakage and a howling sound. This shouldn't be confused with drivebelt slippage, which squeals. The pump is at the engine's front, and a coolant puddle under the vehicle likely means a failed pump seal. Noise from the pump suggests a worn impeller shaft bearing, possibly confirmed by wiggling the drive pulley.

Drain the cooling system and disconnect the radiator and bypass hoses from the water pump. Remove the cooling fans, drivebelt cover, drivebelts, timing belt, and crankshaft pulley. Remove the timing belt tensioner, idler pulley(s), and on turbo models, the CMP sensor and left side camshaft sprockets. Remove the left side rear timing belt cover and belt tensioner bracket. Loosen the water pump bolts, remove the pump and gasket, and clean the engine mounting surface. Ensure bolt threads and engine holes are corrosion-free. Compare the new and old pump, apply sealant to the new gasket and install it on the pump. Apply RTV sealant to bolt threads, align the pump and gasket on the engine, and tighten the bolts in 1/4-turn increments. Reattach hoses, refill the cooling system, and check drivebelt tension.

Except for Forester 2002 and older, you need to drain your cooling system, detach both radiator hose and bypass line from the pump, then detach both cooling radiator fans. You'll first remove the drive belt cover and then take the belts out of place. On engines without a turbo, first you need to take out the tensioner and idler pulley under the water pump, then two parts of the timing belt assembly from the left camshaft, and finally remove the cover from the back of the engine where timing belt runs. For cars with turbo engines, take off these three parts from both sides of the water pump: the timing belt tensioner and idler pulleys sitting just above and below pump, and the camshaft position sensor. You should remove all bolts from the water pump, get the pump and old gasket apart from the engine, and completely take off any residue from the old gasket while cleaning the surfaces. Make sure the replacement pump matches what you took off, put sealant on both sides of a fresh gasket, and place it on the pump. Spread RTV sealant on the threads of each mounting bolt, place the water pump gently, making sure it sits correctly with the gasket, then screw in the bolts without over-tightening. Start with the middle bolt on the right side of the bolts, tighten them clockwise, check the torque rate after, and complete all bolts following this pattern. To finish installing the water pump, you follow the same steps in reverse order: put back all the parts you took out for access, attach the hoses to the pump, use firm grip to turn your hose clamps tightly, top up your cooling system, and make sure your drivebelt is set correctly.

Apply a small amount of RTV sealant to the threads of each mounting bolt.

Both cooling fans from the radiator, drivebelt cover, drivebelts, timing belt, crankshaft pulley, timing belt tensioner, and idler pulley(s) located below (and on turbo models, above) the water pump. On turbocharged engines, the Camshaft Position (CMP) sensor, sprocket(s) from the left side camshafts, left side rear timing belt cover, and mounting bracket for the belt tensioner also need to be removed.