Oil Pump: Inspection

WARNING: This page is about a different car, the 2004 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Oil pump pressure relief valve and spring should not be removed from the oil pump. If these components are disassembled and or removed from the pump the entire oil pump assembly must be replaced.

Clean all parts thoroughly. Mating surface of the oil pump housing should be smooth. If the pump cover is scratched or grooved the oil pump assembly should be replaced.
Lay a straight edge across the pump cover surface (Fig 1 ). If a 0.025 mm (0.001 in.) feeler gauge can be inserted between the cover and the straight edge the oil pump assembly should be replaced.

Fig 1: Checking Oil Pump Cover Flatness
Courtesy of DAIMLERCHRYSLER CORP.
Measure the thickness of the outer rotor (Fig 2 ). If the outer rotor thickness measures at 12.005 mm (0.472 in.) or less the oil pump assembly must be replaced.

Fig 2: Measuring Outer
Courtesy of DAIMLERCHRYSLER CORP.
Measure the diameter of the outer rotor. If the outer rotor diameter measures at 85.925 mm (3.382 in.) or less the oil pump assembly must be replaced.
Measure the thickness of the inner rotor (Fig 3 ). If the inner rotor thickness measures at 12.005 mm (0.472 in.) or less then the oil pump assembly must be replaced.

Fig 3: Measuring Inner Rotor Thickness
Courtesy of DAIMLERCHRYSLER CORP.
Slide outer rotor into the body of the oil pump. Press the outer rotor to one side of the oil pump body and measure clearance between the outer rotor and the body (Fig 4 ). If the measurement is 0.235mm (0.009 in.) or more the oil pump assembly must be replaced.

Fig 4: Measuring Outer Rotor Clearance in Housing
Courtesy of DAIMLERCHRYSLER CORP.
Install the inner rotor in the into the oil pump body. Measure the clearance between the inner and outer rotors (Fig 5 ). If the clearance between the rotors is .150 mm (0.006 in.) or more the oil pump assembly must be replaced.

Fig 5: Measuring Clearance Between Rotors
Courtesy of DAIMLERCHRYSLER CORP.
Place a straight edge across the body of the oil pump (between the bolt holes), if a feeler gauge of .095 mm (0,0038 in.) or greater can be inserted between the straightedge and the rotors, the pump must be replaced (Fig 6 ).

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

NOTE: The 3.7 Oil pump is released as an assembly. There are no DaimlerChrysler part numbers for Sub-Assembly components. In the event the oil pump is not functioning or out of specification it must be replaced as an assembly.