Engine - Oil Leaks From Rear of Vehicle
90cadillac07Bulletin No. T-90-71
File in Group 6A
Number 115
Corp. Ref. No. 716108R
Date May, 1990
SUBJECT: REAR OF ENGINE OIL LEAKS - 4.1L AND 4.5L ENGINES
MODELS AFFECTED: 1982-1985 RWD DE VILLES AND FLEETWOODS 1982-1990 DE VILLES, FLEETWOODS, ELDORADOS, AND SEVILLES 1987-1990 ALLANTES
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:
Longitudinal Engine:
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.
Transverse Engine:
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.
Figure 1 - Main Bearing Cap Imperfections:
IMPORTANT: If the oil pan gasket has been determined to be the source of the leak on either the transverse or longitudinal engine, be sure to check the sealing surface of the rear main cap for casting of machining imperfections. Deep scratches, such as shown in Figure 1, may prevent the pan gasket from sealing. To repair these deep scratches:
first, clean the area thoroughly with solvent such as lacquer thinner or GM fabric cleaner. Next, apply RTV sealant into the blemished area. Clean off excessive RTV and allow RTV to cure for 10-15 minutes before assembling the gasket and oil pan.
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.
NOTE: If black light diagnosis was necessary, add .5 hour to "other hours" of Labor Operation used to repair oil leak.
Parts are currently available from GMSPO.