824517A 1 Mercruiser GEAR SET, (18/25) (1.65:1 Ratio)

Water
Distilled or deionized water is recommended for use in cooling systems. DO NOT use hard, tap water or salt softened tap water in engine cooling systems. If Distilled or deionized water is NOT available, use water that meets the Minimum Acceptable requirements listed in the following chart.
Water that does not meet the Minimum Acceptable limits will reduce engine service life when used in cooling systems.
If you are not sure of your water's contents, contact your Caterpillar dealer, your local water department, agricultural agent, or an independent laboratory to analyze the water.Additives
Additives must be included in all coolant mixtures. Additives help prevent the formation of rust, scale and mineral deposits. Additives protect metals from corrosion, prevent liner cavitation, and contain anti-foaming agents. Additives deplete during engine operation and need to be replenished. This is done through the addition of supplemental coolant additives (SCAs, with conventional coolants) or Extender (with Caterpillar Long Life Coolant/Antifreeze).Nitrites or nitrite and molybdate additives protect the cylinder liner from cavitation corrosion. Nitrites deplete, creating the need for SCAs or Extender. SCAs and Extender also contain other inhibitors that deplete from cooling systems.Under-concentration of additives does not provide the protection required for cooling systems. Over-concentration can cause additives to drop out of solution, deposit inside the cooling system, or form a gel in the radiator. Deposits can be in the form of sludge and scale which accumulate on hot engine surfaces, reducing cooling system effectiveness, or causing water pump leaks.To maintain conventional cooling system protection, it is necessary to monitor SCA concentration. Incorrect SCA concentration requires action to return proper additive levels to the cooling system.Glycol
Engine coolant glycol is normally one of two varieties, ethylene or propylene. Glycol raises the boiling point of water to help prevent boil-over, provides freeze protection, helps prevent water pump cavitation, and reduces cylinder liner pitting.
For ambient temperatures requiring lower freeze protection (higher than 50 percent glycol), use ethylene glycol. DO NOT use propylene glycol.
Proper anti-freeze/boil protection requires the proper ratio of glycol and Acceptable water. Use the following charts to determine glycol concentrations to mix with Acceptable water. Check the coolant solution periodically to ensure adequate anti-freeze/boil protection. Use the 1U7298 Coolant Tester (°C) or the 1U7297 (°F) Coolant Tester. These coolant testers give immediate, accurate readings and can be used with ethylene or propylene glycol. For more detailed specifications, refer to: Know Your Cooling System, SEBD0518, and Coolant and Your Engine, SEBD0970, or contact your Caterpillar dealer.Caterpillar Coolant Recommendations
* Preferred- Caterpillar Long Life Coolant/Antifreeze (LLCA).Conventional Antifreeze/Coolant
* Recommended- Caterpillar Diesel Engine Antifreeze/Coolant (DEAC).* Acceptable- Any low silicate coolant that meets Truck Maintenance Council (TMC) Recommended Practice (RP) 329, TMC RP330, or ASTM D4985 requirements when used with SCAs.* Permitted- A mixture of Acceptable Water and SCA, where freeze protection is not necessary.* Unacceptable- ANY high silicate coolant that is classified as meeting ASTM D3306.
Most commercial engine coolant/antifreezes are formulated for gasoline engine applications and have high silicate content. High silicates provide conditions favoring cylinder liner cavitation and corrosion. Caterpillar DOES NOT recommend these antifreezes.Never operate without thermostats in the cooling system. Thermostats maintain the engine coolant at the proper operating temperature. Cooling system problems can arise without thermostats.Never add coolant water to an overheated engine-engine damage can result. Allow the engine to cool first. Do not add coolant water too quickly. Filling the cooling system at over 19 L (5 US gal) per minute can create air pockets in the cooling system.
Due to individual engine applications, engine cooling system maintenance practices may need periodic re-evaluation.When filling or adding to the coolant to the system, premix the coolant solution prior to pouring it into the cooling system. Pure undiluted glycol will freeze at -23°C (-10°F). Use a mixture in a range which will provide protection to the lowest expected outside (ambient) temperature and provide the required boil-over protection.Caterpillar Long Life Coolant/Antifreeze (LLCA)
Caterpillar's Long Life Coolant/Antifreeze (LLCA) anti-corrosion package is totally different from the conventional antifreezes that have been in use. Caterpillar LLCA is an ethylene glycol based coolant/antifreeze containing organic corrosion inhibitors and anti-foam agents with fewer nitrites than conventional coolants.LLCA was specifically designed for cooling systems in diesel and natural gas engines. LLCA may also be used in automotive applications.LLCA extends coolant life to 6,000 service hours or four years, whichever comes first. The only maintenance required for cooling systems filled with LLCA is one addition of Caterpillar Extender.Major LLCA advantages:* twice the coolant life.* considerably less maintenance.* improved corrosion protection.* better aluminum protection.* better liner protection.* fewer additives (chemicals) and no chemical drop out.* longer radiator life.* increased water pump seal life.LLCA is available premixed 50/50 with deionized water, or in concentrate, in the following quantities. A 50/50 LLCA/water solution provides freeze protection to -37°C (-34°F) and anti-boil protection to 108°C (226°F). DO NOT use LLCA at reduced concentrations (less than 50 percent), since the additives would be reduced along with the antifreeze. LLCA concentrate is available to lower the freeze point for arctic conditions. LLCA concentration can be increased to 60 percent for -52°C (-62°F) freeze protection.Extender
LLCA Extender is a liquid that is poured into the cooling system halfway through the LLCA service life.The cooling system should be treated with Extender at the 3,000 service hour interval or two years, whichever comes first. Use the following table to determine the recommended amount of Extender to add to LLCA. LLCA Cooling System Maintenance
Use only Caterpillar products or commercial products that have passed the CAT EC-1 specification for pre-mixed or concentrate coolants.Use only Caterpillar Extender with LLCA.Mixing LLCA with other products reduces the LLCA service life. Failure to follow the recommend