Chrysler 4781454AC Pump-Engine Oil

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The procedure to uninstall the oil pan involves first, the removal of the timing chain cover; the oil pump cover is then unscrewed from the timing chain cover. They should all be cleaned in solvent and the rotors, pump cover, and timing chain cover should be checked for nicks, scratches, or burrs and the assembly replaced if found. The oil pump cover has to be checked for warpage using a straightedge and a feeler gauge, if past the limit, replace the pump. Using a micrometer measure the thickness of the outer as well as inner rotors and replace the pump when the thickness of any of is not within the recommended limits. Place the outer rotor of the pump into the position on the timing chain cover/oil pump housing; inspect the maximum permissible gap between the rotor and the housing using a thin metal blade; if the maximum admissible gap is exceeded, then to the pump. The mark on the inner rotor should face up, while the clearance between the lobes of the inner and outer rotors should not exceed the predetermined value; if so, the pump must be replaced. A straightedge is used to measure the clearance of the rotors with the oil pump cover, for any distance greater than the limit the pump needs replacing. For installation, tighten the pump cover bolts to the next torque specification, followed by putting the timing chain cover and tightening the corresponding bolts to the next torque specification. Last of all, return all other parts in the reverse sequence it was removed and replace the engine oil together with the oil filter.

The oil pump pressure relief valve can be serviced without removing the oil pan and oil pick-up tube. Begin by disconnecting the cable from the negative terminal of the battery. Next, remove the timing belt, followed by the oil pan and pick-up tube assembly, and then the crankshaft sprocket. Detach the oil pump assembly from the engine by removing the bolts. If the pump does not come off by hand, gently tap it with a soft-faced hammer or pry on a casting boss. Remove the mounting screws and the rotor assembly cover from the oil pump housing, then pull the inner and outer rotors from the body. Exercise caution with these components, as close tolerances are critical for correct oil pressure; any nicks or damage will necessitate replacing the complete pump assembly. Use a hammer and brass drift to remove and discard the crankshaft front seal from the oil pump housing, and also remove and discard the O-ring seal from the oil pump housing discharge port. Disassemble the relief valve assembly, taking note of the installation of the relief valve piston, and remove the cap bolt, washer, spring, and relief valve. Clean all components, including block surfaces and the oil pan, with solvent, inspecting for excessive wear or damage. Check the oil pressure relief valve piston sliding surface and valve spring for damage, replacing them as a set if necessary. Measure the oil pump rotor dimensions and clearances, comparing the results to the specified values, and replace both rotors if any dimension is out of tolerance. For installation, lubricate the relief valve piston, piston bore, and spring with clean engine oil, then install the relief valve piston with the grooved end first, followed by the spring and cap bolt, tightening the cap bolt to the specified torque. Lubricate the oil pump rotor recess and both rotors with clean engine oil, install the rotors in the body, fill the rotor cavity with clean engine oil, and install the cover, tightening the cover screws to the specified torque. Install a new O-ring in the oil discharge passage and apply anaerobic sealant to the oil pump body sealing surface before positioning the pump assembly on the block, aligning the inner rotor and crankshaft drive flats, and tightening the oil pump bolts to the specified torque. Install the new crankshaft front seal in the oil pump housing, followed by the crankshaft sprocket and timing belt. Install the oil pump pick-up tube assembly and oil pan, then install a new oil filter and lower the vehicle. Fill the crankcase with the proper quantity and grade of oil, reconnect the negative battery cable, and after the sealant has cured according to the manufacturer's directions, start the engine and check for leaks.

Insert the outer rotor into the timing chain cover/oil pump housing and check the clearance between the rotor and housing with a feeler gauge; if it exceeds the maximum allowable clearance, replace the pump.

Remove the mounting screws and the rotor assembly cover from the oil pump housing, then pull the inner and outer rotors from the body.

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.

Secure the pump cover by tightening the bolts to the specified torque, align the flats in the rotor with those on the crankshaft when installing the pump, and then attach the timing chain cover, tightening the bolts to the required torque.

Scrape off old gasket material and sealant from the oil pump and engine block mating surfaces, and clean them with lacquer thinner or acetone.