This bulletin supersedes bulletins T-87-71 and T-89-8, Group 6A, which should be discarded. This bulletin is being revised to include a new part number and add 1990 model year. Rear of engine oil leaks are often difficult to pinpoint since there are several potential leak areas. The potential leak areas are as follows:
Rear main seal Oil pan/main cap joint Main cap side seals Cam plug Oil galley plug Oil feed pipe Casting cracks or porosity
To diagnose and repair a leak condition use the following procedure:
1. Remove transmission inspection cover.
2. Visually inspect for oil leak source (i.e., rear main seal, galley plug, etc.).
3. If oil leak cannot be determined by visual inspection, perform black light diagnosis to pinpoint leak source.
4. Repair leak source (transmission removal may be required).
5. In situations where cracks or porosity are found in high pressure passages, engine replacement is required as there are no effective repair techniques.
1. Remove oil feed pipe from engine using procedure from Section 6A of the appropriate Cadillac Service Information Manual.
2. Install new style oil feed pipe, P/N 1649685, which utilizes two O-rings, P/N 1623825, for improved sealing.
3. If leak is still present, R&R transmission.
4. Visually inspect for oil leak source (i.e., galley plug).
5. If oil leak cannot be determined by visual inspection, perform black light diagnosis to pinpoint leak source.
6. Repair leak source.
7. In situations where cracks or porosity are found in high pressure passages or the new style oil feed pipe cannot seal the feed pipe to the block, engine replacement is required as there are no effective repair techniques.
Labor Operations that may be used for engine oil leak repair are listed below. Refer to the appropriate Labor Time Guide to obtain the correct time to submit for warranty claims.
Labor Repair Description Operation
Pipe, Oil Feed - Replace ..................... J0955 Pan and/or Gasket Oil - Replace ..................... J1000 Seal, Engine Rear Main - Replace ..................... J1120 Plug, Oil Galley Rear - Replace ..................... J1641
Parts are currently available from GMSPO.
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.