DIESEL/LOW ENGINE OIL PRESSURE VALVE LIFTER BORE CLEARANCE

Model and Year. 1978-84 IMPALA, CAPRICE, MALIBU, MONTE CARLO, EL CAMINO, CELEBRITY AND C-10 TRUCKS

Low oil pressure may be experienced on a diesel caused by valve lifter to bore clearance. The clearance may occur in the upper end of the bore although the lifter usually wears more than the bore. All wear is toward the center line of the engine. To determine if wear has occurred, measure the upper end of the lifter in two spots, where it contacts the bore, parallel with the roller and 900 to the roller. Wear in the area of .005-.008 inches is enough to cause low oil pressure and the lifter should be replaced.

Measure the lifter bore in the block. Any wear not exceeding .003 inches should be satisfactory. If it is necessary to replace the lifters, stone the sharp edges on the bearing shoulder area of the new lifters as shown in the illustration, before installation in the lifter bore.

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