Oil Pump: Inspection

WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.

Clean all parts thoroughly. Mating surface of the oil pump should be smooth. Replace pump cover if scratched or grooved.

Lay a straightedge across the pump cover surface. See Fig 1. If a 0.076 mm (0.003 in.) feeler gauge can be inserted between cover and straight edge, cover should be replaced.

Fig 1: Checking Oil Pump Cover Flatness

Courtesy of DAIMLERCHRYSLER CORP.

1 - STRAIGHT EDGE

2 - FEELER GAUGE

3 - OIL PUMP COVER

Measure thickness and diameter of outer rotor. If outer rotor thickness measures 7.64 mm (0.301 in.) or less, or if the diameter is 79.95 mm (3.148 in.) or less, replace outer rotor. See Fig 2.

Fig 2: Measuring Outer Rotor Thickness
Courtesy of DAIMLERCHRYSLER CORP.
If inner rotor measures 7.64 mm (0.301 in) or less replace inner rotor. See Fig 3.

Fig 3: Measuring Inner Rotor Thickness
Courtesy of DAIMLERCHRYSLER CORP.
Slide outer rotor into pump housing, press to one side with fingers and measure clearance between rotor and housing. See Fig 4. If measurement is 0.39 mm (0.015 in.) or more, replace housing only if outer rotor is in specification.

Fig 4: Measuring Outer Rotor Clearance in Housing
Courtesy of DAIMLERCHRYSLER CORP.

1 - FEELER GAUGE

2 - OUTER ROTOR

Install inner rotor into pump housing. If clearance between inner and outer rotors is 0.203 mm (0.008 in.) or more, replace both rotors. See Fig 5.

Fig 5: Measuring Clearance Between Rotors

Courtesy of DAIMLERCHRYSLER CORP.

1 - FEELER GAUGE

2 - INNER ROTOR

3 - OUTER ROTOR

Place a straightedge across the face of the pump housing, between bolt holes. If a feeler gauge of 0.102 mm (0.004 inch) or more can be inserted between rotors and the straightedge, replace pump assembly. See Fig 6. ONLY if rotors are in specs.

Fig 6: Measuring Clearance Over Rotors
Courtesy of DAIMLERCHRYSLER CORP.

1 - FEELER GAUGE

2 - STRAIGHT EDGE
Inspect oil pressure relief valve plunger for scoring and free operation in its bore. Small marks may be removed with 400-grit wet or dry sandpaper.
The relief valve spring has a free length of approximately 60.7 mm (2.39 in.) it should test between 18 and 19 pounds when compressed to 40.5 mm (1.60 in.). Replace spring that fails to meet specifications.
If oil pressure is low and pump is within specifications, inspect for worn engine bearings, damaged or missing oil pick-up tube O-ring, clogged oil pick-up tube screen, clogged oil filter and stuck open pressure relief valve or other reasons for oil pressure loss.