How Should I Care for my Cooling System?

The first step for cooling system care is making sure you’re using the proper fluids. Either distilled or deionized water should be used with an approved antifreeze and an approved supplemental coolant additive or rust inhibitor. (Fishermen in warmer climates don’t need to use antifreeze but must still use the coolant conditioners.) Use a low-silicate antifreeze that meets one of the following specifications: GM 6038-M or ASTM #D4985. The fluid in the jacket water cooling system should not consist of plain tap water or water which has been “softened” by a domestic water softener. Tap water is not recommended for engine cooling systems because of additives, contaminants and other chemicals (such as salt, chlorides, sulfates, etc.) found in the water.

Corrosion of the water-cooled side of cylinder liners can occur when supplemental cooling system conditioners are not used or are depleted. Jacket water systems should always be filled with a Caterpillar approved coolant mixture, a 50-50 mixture of distilled water and an approved glycol base antifreeze containing approved corrosion inhibitors or distilled water, plus an approved cooling system conditioner.

Here are some additional tips to incorporate into your regular maintenance schedule to keep your cooling system in good shape:

Replace hoses approximately every three years of engine operation.

  • Replace the fluid in the cooling system or replenish the inhibitor chemicals at intervals listed in your owner’s manual. Although the glycol in the antifreeze mixture does not wear out, the corrosion inhibitors lose their effectiveness over time. You can eliminate the need for multiple additive replacements by using the new Cat® Extended Life Coolant, which requires only one addition of “extender” at 3,000 hours or three years.
  • Consider a coolant analysis program, such as the S•O•℠ coolant analysis offered by Caterpillar Inc., to evaluate the effectiveness of your coolant and check for contaminants.
  • Clean the water pump drain vent and inspect for leakage of the pump seal.
  • Inspect and maintain the sea water coolant system. Clean the sea water strainer, check the pump impeller at least annually (or monthly for rubber impeller pumps) and periodically clean the heat exchangers.
  • Periodically inspect and replace zinc anodes used in the seawater system.
  • Check coolant level before starting the engine.
  • Ensure that the engine room ventilation system is adequate.

In addition, the filler cap on pressurized cooling systems includes a valve that permits the system to operate at above atmospheric pressure. Pressurizing the jacket cooling system increases the boiling point of the coolant, increasing the efficiency of the cooling system. Fluid level in this type of system is normally checked when the engine is cool.

Proper engine cooling system operation is best achieved by always performing all required inspections and checks. It may take some extra work, but it’s better than having to deal with an overheated engine.


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