How to Replace an Oil Pump in a Subaru Outbackby Contributor
An oil pump is a necessary tool for the survival of the engine. It keeps the engine components in the Subaru Outback lubricated. Without lubrication, an engine is destroyed. In most cases you don't need to replace an oil pump, but in some cases, such as an engine overhaul, you might want to.
Remove the Oil Pump
Drive your Subaru Outback up onto ramps or lifts so you have room to work as you pull out the oil pump. You could also use a jack, but make sure you brace the front wheels so they don't roll. In addition, set the emergency break firmly into position so the car doesn't roll.
Disconnect the negative battery cable then take off the engine undercover. Drain the air conditioning coolant.
Take out the radiator main fan and the sub fan assemblies if you have an Impreza model. Take out the radiator if you have a Legacy model.
Disconnect the crankshaft and camshaft position sensors then remove the drive belts. Continue component removal by taking out the rear side V-belt tensioner, the crankshaft (using a good crankshaft removal tool), the water pump, the timing belt guide (if it has a manual transaxle) and the crankshaft sprocket.
Remove the oil pump mounting bolts and the oil pump itself, gently prying it from the engine block.
Install the Oil Pump
Take some measurements and replace components if they do not meet the following specifications: The tip clearance of the rotors should be under 0.0071 inches; the clearance between the outer rotor and the cylinder block rotor housing should be less than 0.0079 inches; and the side clearance between the oil pump inner rotor and the pump cover should be less than 0.0059 inches.
Put your new oil pump together and apply sealant to the new O-ring as well as the oil pump. Install the oil pump, torquing the bolts to 60 in-lb.
Connect or install the following components in order: the crankshaft sprocket, the timing belt guide (if you took it out), the water pump, the crankshaft pulley (using the special tool again), the rear side V-belt tensioner, the drive belts, both sensors you removed previously, the radiator (for Legacy models), the radiator main fan and sub fan assemblies (on Impreza models) and the engine cover.
Reconnect the battery cable then fill and bleed the cooling system. Start the engine on your Subaru Outback and look for leaks around your new oil pump.