GM Full-Size Trucks 1980-1987 Repair Guide

Oil Pump



See Figures 1 and 2

The oil pump is mounted to the bottom of the block and is accessible only by removing the oil pan.

  1. On all engines, including diesel, remove the oil pan.
  3. Unbolt and remove the oil pump and screen as an assembly. On the in-line sixes, remove the flange mounting bolts and nut from the elongated number 6 main bearing cap bolt, then remove the pump.

To install:
  1. Prime the pump with clean motor oil.
  3. Align the oil pump drive shaft on the in-line 6 cylinder engines to match with the distributor tang and position the pump flange over the distributor lower bushing. Install the pump mounting bolts.
  5. On V6 and V8 engines, insert the drive shaft extension through the opening in the main bearing cap until the shaft mates with the distributor drive gear. You may have to turn the drive shaft extension one way or the other to get the two to mesh. Position the pump on the cap and install the attaching bolts.
  7. Install the oil pans on all engines.

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Fig. Fig. 1: Oil pump installation

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Fig. Fig. 2: Oil pump exploded view