ENGINE OIL LEAKS IDENTIFICATION/SERVICE PROC.). Cadillac DeVille 1994

REVISION: 12/20/95

THIS BULLETIN IS BEING REVISED TO CORRECT THE ILLUSTRATION IN FIGURE 3. PLEASE DISCARD BULLETIN 476003 (GROUP REFERENCE 6-ENGINE). **********************************************************************

SUBJECT: ENGINE OIL LEAKS (IDENTIFICATION/SERVICE PROCEDURE)

MODELS: 1993 CADILLAC ALLANTE 1993-1994 CADILLAC ELDORADO AND SEVILLE 1994 CADILLAC CONCOURS

SOME OWNERS MAY EXPERIENCE OIL LEAKS IN THE CRANKCASE AREA OF THE ENGINE. THE FOLLOWING INFORMATION IDENTIFIES THE MOST COMMON AREAS OF OIL LEAKS AND THE REPAIR PROCEDURES TO CORRECT THEM.

1. OIL FILTER ADAPTER. LEAKS IN THIS AREA HAVE BEEN CAUSED BY CRACKS IN THE HOUSING DUE TO OVER TIGHTENING OF THE MOUNTED BOLTS AND/OR THE OIL COOLER LINE COUPLINGS. OIL MAY ALSO LEAK BY THE O-RINGS BETWEEN THE ADAPTER AND THE BLOCK (REFERENCE CADILLAC SERVICE BULLETIN T-93-39 - CORPORATE BULLETIN 216108R). CHECK FOR FLATNESS ON THE CRANKCASE SURFACE. IF THE SURFACE IS NOT FLAT, HONE THE SURFACE UNTIL AN ADEQUATE SEALING SURFACE IS OBTAINED. THE O-RINGS WERE REDESIGNED EARLY IN THE 1993 MODEL YEAR. TO CORRECT LEAKS IN THIS AREA, REPLACE THE ADAPTER, O-RINGS AND INSTALL BOLTS WITH CONICAL WASHERS. TORQUE ON THE BOLTS WITH CONICAL WASHERS SHOULD BE 16 N.M (12 LBS. FT.).

2. REAR MAIN SEAL. THE REAR MAIN SEAL MAY BE MISPOSITIONED DURING ASSEMBLY. IN THIS CASE, THE SEAL WILL BE CROOKED IN THE BLOCK. A PROPERLY INSTALLED SEAL SHOULD BE SEATED 0.5 MM BELOW THE SURFACE OF THE BLOCK FACE AROUND THE ENTIRE SEAL (FIGURE 1). TO REPAIR THIS CONDITION, INSTALL A NEW SEAL USING KENT-MOORE TOOL J38817.

3. CRANKCASE HALVES. THERE ARE TWO MAIN REASONS FOR LEAKS IN THE CHANNEL BETWEEN THE UPPER AND LOWER CRANKCASE. THE FIRST IS A CUT/ DAMAGED SEAL USUALLY DAMAGED AT THE ENDS. THE SEAL CAN BE REPLACED TO CORRECT LEAKS IN THIS AREA. THE SECOND REASON IS THE LOWER CRANKCASE SEALING SURFACE MAY HAVE AN IMPERFECTION ON ITS SURFACE WHICH DOES NOT ALLOW PROPER SEALING OF THE SEAL. THE SEAL LEAVES A WITNESS MARK ON THE LOWER CRANKCASE, WHICH SHOULD BE INSPECTED FOR ANY IRREGULARITIES. INSPECT THE LOWER CRANKCASE SEALING SURFACE FOR NICKS, SCRAPES, GOUGES AND PUCKERS. THE SURFACE SHOULD BE CAREFULLY WORKED TO PROVIDE A SMOOTH SEALING SURFACE. IF A SMOOTH SURFACE CANNOT BE ATTAINED, THE ENGINE MUST BE REPLACED.

NOTICE: USE CARE WHEN PRYING NOT TO DAMAGE THE LOWER CRANKCASE SURFACE. DO NOT KEEP PUSHING YOUR PRY TOOL INTO THE CRANKCASE AS THE UPPER AND LOWER CRANKCASE HALVES SEPARATE. THIS MAY DAMAGE THE SEALING SURFACE (FIGURE 2).

4. LIFTER GALLEY PLUG. LEAKS AT THE REAR ENGINE AREA MAY HAVE BEEN CAUSED BY A CROSS THREADED OR LOOSE LIFTER GALLEY PLUG (FIGURE 3). TOW PLUGS ARE IN THE REAR OF EACH CYLINDER HEAD, WITH THE INBOARD PLUG LOCATED BEHIND THE COOLANT CROSSOVER. IF A LEAK IS FOUND, REMOVE THE PLUG AND INSTALL CORRECTLY. THE PLUG HAS SEALANT ON IT AND IS REUSABLE.

FIGURES: 3 ATTACHMENTS: 0

Object Number: 82935 Size: FS

Object Number: 84068 Size: FS

Object Number: 84067 Size: SH

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER." THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS OCCURRING 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 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.