WASHER-HARD 9H1031 - Caterpillar

You must read and understand the warnings and instructions contained in the Safety section of this manual before performing any operation or maintenance procedures.Before proceeding with this maintenance, perform previous maintenance interval requirements.Water Temperature Regulators (Thermostats)
Replace
Caterpillar recommends the replacement of these thermostats on a regularly scheduled basis to be the most cost effective way to operate the engine.
Typical ExampleReplacing the thermostats is a good preventive maintenance practice because it reduces the chances for unscheduled downtime. Failure to replace thermostats on a regularly scheduled basis could cause damage to cooling system and other engine components.Caterpillar engines may incorporate a shunt design cooling system which require operating the engine with thermostats.If thermostats fail in the closed position, it will cause excessive engine overheating and could result in cylinder head cracking or piston seizure problems.If thermostats fail in the open position, the engine oil and operating temperature could be too low during partial load operation and could cause an excessive carbon build-up inside the cylinder. This excessive carbon build-up could result in accelerated piston ring and cylinder liner wear.* Before proceeding with this maintenance, perform additional cooling system maintenance procedures unless replacing these thermostats ONLY.* If performing this complete maintenance interval, continue to additional cooling system maintenance procedures.Removal and Installation
* If replacing thermostats prior to this maintenance interval, refer to the Service Manual for disassembly and assembly procedures to replace the thermostats as required in the Maintenance Schedule or contact your Caterpillar dealer for assistance.Oil Temperature Regulators (Thermostats)
Replace
Caterpillar recommends the replacement of these thermostats on a regularly scheduled basis to be the most cost effective way to operate the engine. Excessive oil overheating could result in accelerated piston ring and cylinder liner wear. * Before proceeding with following steps, perform additional cooling system maintenance procedures unless replacing these thermostats ONLY.* If performing this complete maintenance interval, continue to additional cooling system maintenance procedures.Removal and Installation
Refer to the Service Manual for disassembly and assembly procedures to replace the thermostats as shown in the Maintenance Schedule, or contact your Caterpillar dealer for assistance.Cooling System
Clean/Flush Coolant
Do not perform this maintenance until you read and understand the material in the Safety and Cooling System Specifications sections of this publication.This procedure is to be used for normal maintenance of cooling systems surfaces to return to "like new" condition. For heavy build-up of scale and deposits, a severe acid-type, commercial cleaner or mechanical cleaning will be required.
Add Cooling System Cleaner
Approximately one week prior to draining the cooling system, add 19 liter (5 U.S. gallon) of Caterpillar Cooling System Cleaner (4C4612) for every 300 liter (80 U.S. gallon) of cooling system capacity. Continue to operate the engine for one week before draining.Performing maintenance on the cooling system is important because the cooling system has a direct effect on the operation and service life of the engine. Improper maintenance can result in a variety of problems that could shorten the engine's service life, reduce the efficiency of the cooling system, result in poor engine performance, and in some