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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 88 (3.3L V6 CNG - VIN [J]) >> Engine Oiling >> Oil Pump >> Inspection

Oil Pump: Inspection

WARNING: This page is about a different car, the 1995 Plymouth Voyager, 1995 Plymouth Grand Voyager, 1995 Dodge Grand Caravan, and 1995 Dodge Caravan. However, it is still accessible from the selected car via links, so may be relevant.
  1. Inspect components for damage. Using straightedge and feeler gauge, check the pump cover warpage. Replace the pump cover if the clearance is equal to or exceeds the specification. Refer to the OIL PUMP SPECIFICATIONS  table.
  2. Measure thickness of both rotors and outer rotor O.D. Replace rotors if measurement is equal to exceeds specification.
  3. Install outer rotor in timing chain cover. Press outer rotor against one side of timing chain cover. Measure outer rotor-to-timing chain cover clearance. If clearance is equal to or exceeds specification but outer rotor O.D. is within specification, replace timing chain cover.
  4. Install inner rotor in timing chain cover. Measure clearance between inner and outer rotors. Replace both rotors if clearance is equal to or exceeds specification.
  5. Place straightedge across timing chain cover surface, above both rotors. Using feeler gauge, measure rotor end clearance between rotors and straightedge. Replace both rotors if clearance is equal to or exceeds specification if rotor thickness is within specification.
  6. Ensure pressure relief valve slides freely in bore. Check pressure relief valve spring free length and pressure. Replace spring if not within specification.
OIL PUMP SPECIFICATIONS

Application Specification
Inner Rotor-To-Outer Rotor Clearance .008" (.20 mm)
Outer Rotor O.D. 3.148" (79.95 mm)
Outer Rotor-To-Timing Chain Cover Clearance .015" (.38 mm)
Pressure Relief Valve Spring
Free Length 1.95" (49.5 mm)
Pressure (1) 19.5-20.5 @ 1.344 (8.8-9.3 @ 34.14)
Pump Cover Warpage .003" (.08 mm)
Rotor End Clearance .004" (.10 mm)
Rotor Thickness .301" (7.65 mm)
(1) Lbs. @ In. (kg @ mm).