90192 Mercury SCREW, (.250-20 x .750)

Introduction
© 2015 Caterpillar All Rights Reserved. This guideline is considered Caterpillar Confidential Green.Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made in order to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.For questions or additional information concerning this guideline contact your Caterpillar Dealer Technical Communicator:Important Safety Information
Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools in order to perform these functions properly. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure that it is safe for you and for other people to use. Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.
Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death.Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information.
Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.The hazards are identified by the safety alert symbol which is followed by a signal word such as danger, warning, or caution. The "" safety alert symbol is shown below.
Illustration 1 g00008666
This safety alert symbol means:Pay attention!Become alert!Your safety is involved.The message that appears under the safety alert symbol explains the hazard. Operations that may cause product damage are identified by "" labels on the product and in this publication.Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.Summary
Caterpillar has found that many head gasket failures are due to improper inspection/repair of the liner seats. The liner seats in the cylinder block must be inspected after a head gasket failure or during engine overhaul. The liner seat is important in controlling liner projection as well as the location of the liner. Failure to inspect and repair the liner seat will result in premature head gasket failure. Premature head gasket failure, due to the need for liner seat repairs, will not be covered under Caterpillar parts warranty.Note: Do not use a rotary wire wheel to clean the spacer plate. Excessive cleaning to the plate will cause deformation.Cylinder Block Top Deck Surface Inspection
Inspection of the cylinder block top deck, especially in the liner seat area, is critical to head gasket life. A visual inspection of the liner seat area will determine if the block is reusable. Head gasket failure and / or liner flange cracks can result from an irregular surface on the liner seat area regardless of liner projection results. If the block needs to have the liner seats counter bored contact your local Caterpillar dealer. Your Caterpillar dealer will have the latest documentation and the capability to machine the cylinder block and install liner seat inserts. Note: The liner seat of the cylinder block must be inspected to ensure that it is usable as is or if liner seat inserts must be installed prior to the installation of the liner. Anytime the cylinder head is removed liner projection should be measured. Refer to Testing and Adjusting Cylinder Liner Projection – Inspect for more information on how to measure liner projection. Additionally, special consideration should be given to other areas such as the spacer plate joint to ensure proper sealing and long-term reliability.If any of the following are true, cylinder block machining and installation of liner seat inserts is necessary.
Lack of original machining marks in the liner seat area
Fretting, erosion, pitting, or corrosion in the liner seat area
Liner projection is not within specification
Engine block life is greater than 750,000 Miles or 15,000 hours
Cylinder head is being removed because of a liner flange failure or a cylinder head gasket failure following an overhaul or previous head gasket repair
Engine is being overhauled for a second time and liner seat inserts were not installed during first overhaulTop Deck Visual Inspection
The following inspection process should be followed carefully. Any evidence of top deck wear, fretting, corrosion, pitting, or erosion should be addressed during the repair.
Illustration 2 g03817612
Machining marks present across the entire deck including the liner seat areas. USE AS IS. NO MACHINE WORK REQUIRED
Illustration 3 g03817616
A closer view of the