To remove the oil pump, first take off the oil pan, then remove the oil pump mounting bolts and, if present, the brace bolt before extracting the oil pump assembly. For inspection, lift off the oil pump cover after removing the bolts, and check the rotor end play using feeler gauges and a straightedge. Next, remove the outer rotor to measure its thickness with a micrometer, and check the clearance between the inner and outer rotor tips as well as the outer rotor-to-pump body clearance using feeler gauges. Inspect the oil pump cover for warpage with feeler gauges and a straightedge. After that, remove the cotter pin and cup to extract the spring and oil pump relief valve from the pump housing, measuring the free length of the relief valve spring. Compare all measurements to the oil pump specifications; if any are outside the limits, replace the pump. For installation, apply a thin coat of RTV sealant to the mating surface of the pump, position it, and ensure positive contact with the engine block by rotating it slightly. Coat the threads of the mounting bolts with sealant, hold the pump securely, and install the bolts, tightening them to the specified torque. Install a new O-ring in the oil pump pick-up opening, lubricate it, and carefully work the pick-up tube into the pump, securing it with the retaining bolt. Finally, install the brace bolt and tighten it securely before reinstalling the oil pan.