18NA073
Service Bulletin Details
Public Details for: 18NA073
This bulletin provides graphics, information and guidelines for engine component wear to assist service personnel as a guideline to perform necessary engine repairs and prevent unnecessary engine replacement.
- 2020 - 2019 - 2018 - 2017 - 2016 - 2015 -
Models from 2020
Models from 2019
Models from 2018
Models from 2017
Models from 2016
Models from 2015
Bulletin No.: Service Bulletin Date: 18-NA-073 February, 2020 INFORMATION Subject: Repair Guidelines for Engine Component Wear Brand: Model: GM Passenger Cars and Trucks Model Year: VIN: from to from to 2015 2020 All All Engine: Transmission: All - Involved Region or Country North America, Europe, Russia, Middle East, Iraq, Israel, Palestine, Argentina, Brazil, Bolivia, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay, Venezuela, Japan, Cadillac Korea (South Korea), GM Korea Company, China, Taiwan, Thailand, Singapore, Philippines, Australia, New Zealand, Egypt, Other Africa, South Africa Condition Whenever engines have been disassembled, technicians may encounter some visible engine wear characteristics on critical engine components. Some technicians may be replacing engines instead of repairing and replacing worn components as needed. Cause These conditions may be caused by the vehicle duty cycle, dust in the environment the vehicle is being operated in and local fuel quality. In some instances, service personnel may be improperly diagnosing normal engine wear. Correction Review the following graphic examples and information in this bulletin. Information The purpose of this bulletin is to assist the service personnel with graphics and information to use as guidelines in order to perform the necessary engine repairs and prevent unnecessary engine replacement. Important: Prior to component replacement: Refer to SI to diagnose and identify the root cause of the original failure. In cases involving suspected bearing failure, remove and inspect the oil filter (Refer to the Oil Filter – Inspect for Excessive Debris section in this bulletin.). Important: Prior to completing repairs, do a cost analysis; in some instances, an engine replacement may be considered. Important: If SI diagnosis leads to an inspection of the cylinder bores and reveals cylinder wall damage (i.e. excessive scoring or out-of-round), an engine replacement may be required. Refer to the Cylinder Bore section in this bulletin (additional reference: PIP5163D). Camshaft Review the following: 4994025 Example of minor scratching/scoring visible on camshaft lobes and/or camshaft bearing journals. In this example, the scored components can be replaced without need for engine assembly replacement. Copyright 2020 General Motors LLC. All Rights Reserved. Page 2 February, 2020 Camshaft Bearing Caps Review the following: 4991477 Example of minor scratching/scoring visible on camshaft bearing caps. In this example, the scored components can be replaced without need for engine assembly replacement. Connecting Rod End Caps and Bearings Review the following: 4992132 Example of minor scratching/scoring visible on connecting rod bearings. In this example, the scored components can be replaced without need for engine assembly replacement. Bulletin No.: 18-NA-073 Bulletin No.: 18-NA-073 February, 2020 Page 3 Crankshaft in Crankcase Review the following: 4990880 Example of minor scratching/scoring visible on crankshaft. In this example, the scored components can be replaced without need for engine assembly replacement. Crankshaft Main Bearings and Journal Review the following: 4986379 Example of minor scratching/scoring visible on crankshaft. In this example, the scored components can be replaced without need for engine assembly replacement. 4985936 Page 4 February, 2020 Bulletin No.: 18-NA-073 Crankshaft, Reluctor Ring and Journal Review the following: 4986393 4992739 Example of minor scratching/scoring visible on cylinder wall. In this example, if you cannot catch a toothpick or fingernail on the scratch, the cylinder bore / engine block does not require replacement. If the piston is slightly scored, the scored piston can be replaced without need for engine assembly replacement (additional reference: PIP5163D). Cylinder Bore Honing Marks Review the following: 4990640 Example of minor scratching/scoring visible on crankshaft. In this example, the scored components can be replaced without need for engine assembly replacement. Cylinder Bore Review the following: 4993413 Bulletin No.: 18-NA-073 February, 2020 Page 5 Example of minor scratching/scoring visible on piston. In this example, inspect for broken and/or stuck rings and piston ring lands and cylinder wall for damage. If no cylinder wall damage or other significant damage, components can be replaced without requiring an engine assembly replacement. Oil Filter — Inspect for Excessive Debris In cases involving suspected bearing failure, remove and inspect the oil filter for excessive debris and damaged pleats. Use the inspection as an indicator of the amount of material that is displaced through the engine and lubrication circuits. This may help to avoid unnecessary engine removal. Review the following: 4993544 Some technicians may be replacing entire engine assemblies due to marks found at the top of the cylinder bore. These marks are considered normal and are left as a result of a manufacturing laser honing process. DO NOT replace the cylinder block or the engine for these normal laser honing marks (refer to PI0725B). Piston Review the following: 4994104 4992916 Page 6 February, 2020 Bulletin No.: 18-NA-073 4994257 4994408 Shown are oil filter pleats with visible metal particles. In this example, minimal amounts of metal particles are visible on oil filter pleats and should not pose a concern. If excessive amounts of metal particles are observed, or if there is evidence of damaged oil filter pleats, then unfiltered oil with bearing debris may have been pumped into the oil lubrication galleries throughout the engine. This will require further inspection to confirm the degree of contamination and appropriate repair direction (Refer to Service Bulletin 19-NA-256 for HFV6 Gen 1 and Gen 2). Version Information Version 2 Modified Released March 07, 2018 February 07, 2020 – Added the 2020 Model Year, updated the Involved Region or Country section, updated some PI references and changed the bulletin reference in the Oil Filter – Inspect for Excessive Debris section. GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these 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 your GM dealer for information on whether your vehicle may benefit from the information. WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION