OIL PUMP DAMAGE FROM PAN REMOVAL - LOOSEN MOUNT SCREWS

SUBJECT: OIL PAN REMOVAL MAY CAUSE OIL PUMP HOUSING DAMAGE ON 4.9L (VIN B) ENGINES. REVISED PROCEDURE TO UPDATE SERVICE INFORMATION MANUALS - SECTION 6A

MODELS AFFECTED: 1991-1992 DE VILLES, FLEETWOODS, ELDORADOS, SEVILLES

This bulletin supersedes T-92-65 which should be discarded. This bulletin is being revised to add a "T" operation for grinding the oil pan to provide proper clearance on assembly.

When removing the oil pan on 4.9L engines, the edge of the oil pan gasket surface may bind against the transaxle housing near the engine flywheel. If a binding condition exists, it is necessary to loosen the oil pump mounting-flange and screws (2) from engine to lock to allow for unrestricted oil pan removal.

NOTE: Prying on the oil pan can damage the oil pump housing at the mounting flanges.

The following procedure should be used when removing the engine oil pan. This procedure supersedes the steps listed in the applicable Service Information Manuals.

1. Disconnect the negative battery cable.

2. Raise car.

3. Remove oil drain plug and drain oil.

4. Remove two plastic flywheel covers. Refer to Figure 1.

5. On Eldorados and Sevilles remove the exhaust cross-under pipe.

6. Remove oil pan bolts and lower the pan until the edge of the pan contacts the transaxle housing near the flywheel.

7. Loosen the oil pump mounting flange and screws (2) from engine block, do not remove. Refer to Figure 2.

8. Carefully pry down 1/8" on oil pump supply tube then remove the oil pan.

9. If removing oil pan only, check the position of the pump's outlet pipe 0-ring and seat if necessary. Retorque the pump to block with two screws (20 Nm/15 lbs ft.).

10. Grind 1.5mm (1/16") from the two points on the edge of the oil pan where the binding condition was noted. Refer to Figure 3.

To reassemble install the oil pan and perform steps 1-6 in reverse order after solvent and alcohol cleaning both oil pan and block pan rail surfaces.

NOTE: It is necessary to grind the oil pan for proper clearance on assembly. Once a pan has been modified for clearance it is not necessary to loosen the oil pump if subsequent oil pan removal is required. For this operation use T6661 at .2 hour.

For warranty purposes use Labor Operation J1000 at 1.6 hours on DeVilles and Fleetwoods or 1.8 hours on Eldorados and Sevilles.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.