PROPERLY WORKING COOLING SYSTEM PON-CAT.COM/KNOWLEDGE

The importance of a properly working cooling system HOW DOES A COOLING SYSTEM WORK? A cooling system ensures that thermal energy in an engine is dissipated to maintain optimal temperature and engine operation. This thermal energy (heat) arises from the combustion process, internal friction between engine parts, and compression of the intake air through the turbocharger. More than 40% of engine problems are caused or worsened by the cooling system. Clearly, to run the engine without problems it is important to choose the correct coolant and properly maintain the cooling system. This white paper provides an overview of the workings of cooling systems and coolants.

COOLING SYSTEMS All combustion engines produce heat that is released by combustion, friction, and turbocharger compression. Temperatures can rise as high as 2,000ºC and can cause a lot of damage to the engine. Cooling is needed for pistons, bearings, cylinder heads, lubricating oil, scavenging air, and so on. For example, the cylinders' temperature must be controlled so that the lubricating oil has the proper viscosity to form a protective layer on the lining surface. The lubricating oil must also be cooled to allow this to happen. Overheating of engine components, oil, or scavenging air will damage the engine. Overcooling reduces the performance of the engine and results in a shorter lifespan. Overcooling will result in a temperature that is too low, causing performance loss, smoke, can cause corrosion, and so on. Therefore, the cooling system must function properly and be properly maintained.

BASIC PRINCIPLES FOR A TYPICAL COOLING SYSTEM Figure 1 shows the basic elements in a cooling system. A cooling system comprises coolant, a pump, a heat exchanger for the lubricating oil, a heat exchanger for the scavenging air, a heat exchanger for the coolant, and a thermostat. In many cooling systems, the heat in the lubricating oil and the scavenging air is transferred via a heat exchanger to the engine coolant. The heat in the engine coolant can be dissipated through various mediums. In most cases, the medium is water or air. When the medium is air then a radiator with a fan is used to help dissipate the heat.

Figure 1: Cooling system When the engine is running, the pump pumps coolant through the engine oil casing, scavenging air cooler, and in the cylinder block. The coolant flows through the cylinder block, round the cylinders, and then around the hot components of the cylinder head(s). Once past the cylinder heads, the coolant

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flows to the thermostat(s). If the engine is cold, the thermostat by-passes the heat exchanger and sends the un-cooled coolant directly back to the pump, and then the coolant starts the cycle again. As the cooling water temperature approaches the proper operating temperature, the thermostats will open and let some coolant flow to the heat exchanger. As the temperature changes, the thermostat opens and closes to maintain the proper engine temperature. The measure by which [magnitude of how much] the thermostat opens depends on the engine load and the coolant temperature. The coolant in this heat exchanger is cooled down because water or air is blown around the pipes that the coolant is pumped through. The water or air dissipates the heat. Once past the heat exchanger, the cooled coolant goes back to the pump where the “hot” by-pass stream and the “cold” cooled stream merge and mix to the correct temperature. The coolant at the right temperature is now sent to the suction side of the pump where it starts the cycle again.

HEAT DISSIPATION The following components are involved in the transfer of heat: cylinder cooling water, lubricating oil cooler, air cooler, and the cooler going to the external medium. The coolant absorbs the heat in the system and transfers it out via a radiator, or similar. The lubricating oil in a modern engine does more than reduce the friction between moving parts. The lubricating oil also absorbs heat and therefore also has to be cooled for it to work efficiently.

COOLANT QUALITY Cooling system problems can seriously damage important engine parts. These problems are often caused by a low quality coolant. Low quality cooling water accelerates problems such as cavitation, corrosion, and failing pump seals. Low quality coolant occurs through usage of the bad water, insufficient cooling additives, not topping up the system, or coolant that is too old. A lot of attention is often given to the quality of fuel and lubricating oil. However, the quality of the coolant is just as important. Serious engine problems can be prevented by choosing the correct quality of coolant. Caterpillar’s Extended Life Coolant is formulated so that is offers the best resistance against the above dangers and is specifically designed for a Caterpillar engine. This coolant lasts twice as long as ordinary coolant. No further additives are needed, which lowers maintenance costs for the cooling system by 45%.

COOLANT FUNCTION The engine cooling system must perform according to specifications that are determined by the circumstances in how the engine is used. At all times, the coolant must have the following properties: • The coolant must transfer heat efficiently. • The product must be suitable for the materials in the cooling system, such as the rubber in hoses and seals, and, the metals in coolers, thermostats, and pumps. • It must protect against cavitation. • It must protect against freezing and boiling. • It must prevent or limit the build up of corrosion, sludge, and scale.

COOLANT COMPOSITION Coolant usually consists of three elements: water, glycol, and additives. Water is used because it is an efficient cooling medium and is easily available. However, every water source is contaminated in one form or other. This is why Caterpillar recommends that distilled or de-ionized water be used. Glycol protects against freezing. The additives protect against problems such as corrosion, formation of mineral deposits, scale, foaming, and cavitation.

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RECOMMENDED COOLANT Additives must be added to the coolant to resist corrosion, cavitation, contamination, and so on. You can add these additives to water yourself or use ready-made products made by the manufacturer. A ready-made product must comply with the EC-1 standard. Caterpillar and Pon Power recommend this choice because you can then be assured that the cooling medium is formulated in the correct ratios. Pon Power recommends the following cooling mediums and cooling water treatment chemicals: • Caterpillar Extended Life Coolant Premix 50/50 (ELC) EC-1 • Caterpillar Concentrate EC-1 40% mixed with water 60% • Pon Power Extended Life Inhibitor (ELI) • Cooling water treatment chemicals based on nitrite (Nalcool 2000) Caterpillar Extended Life Coolant Premix 50/50 (ELC) EC-1 Caterpillar and Pon Power especially recommend Cat ELC. This coolant is a pre-mixed ready-made formula and has a lifespan twice as long as ordinary products, it offers protection against corrosion, lengthens of the lifespan of pump seals and the radiator, and provides frost protection to -37 ºC. Most importantly, Cat ELC requires less maintenance. ELC premix can be used without additional additives. ELC premix has a lifespan of 12,000 hours and must be upgraded after 6,000 hours with ELC Extender. Extended Life Coolant must be monitored every three months with a Refractometer (Cat part # 2455829) to ensure that it has the correct concentration. The Refractometer is used to accurately determine the correct quantities of additives in the coolant. ELC Concentrate mixed with water ELC Concentrate is a fluid that consists of antifreeze and additives that are added to the cooling water. The correct dosage of additives provides a frost protection of –24 ºC. When monitoring and preserving the correct dosages, the frost protection must be kept at –24 ºC. Extended Life Coolant must be monitored every three months with a Refractometer (Cat part # 245-5829) to ensure that it has the correct concentration. The Refractometer is used to accurately determine the correct quantities of additives in the coolant. Pon Power Extended Life Inhibiter (ELI) ELI is an additive for cooling water in installations when there is no need for frost protection. The quantity of additive in the cooling water is expressed in Brix percentages. The Brix percentage measured with a Refractometer (Pon 333002) must not fall under 5 % or exceed 10 %. The preferred measure is about 7.5% additive. ELI offers no protection against freezing. Nalcool 2000 (Nitrite) Various cooling water treatment chemicals based on nitrite are available. Pon Power recommends the Nalcool 2000 product. At all times when using Nalcool 2000, the concentration must be kept at 3 percent regardless of the concentration of antifreeze. In practice, this is minimally 1,200 ppm of NaNO³. Which is the active ingredient in Nalcool 2000. Nalcool 2000 is not suitable for use in Caterpillar engines fitted with aluminum parts. Use the Pon 202001 test-set or the 4C9301 test-strips to monitor the concentration of Nalcool 2000 in the coolant. The test-set monitors the nitrite concentration in the cooling water, but does not give any indication of the glycol level. This test-kit has a limited storage life (see instruction leaflet). N.B.: Nalcool 2000 offers no protection against frost and cannot be mixed with the standard antifreeze products available on the market. For this purpose, use Mono Ethylene Glycol antifreeze. In addition, Nalcool 2000 is poisonous. The product must not be ingested and can cause irritation to the skin and eyes. For more information, contact your contact person with Pon Power.

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Nalcool 2000 frost protection Nalcool 2000 mixed with antifreeze (Mono Ethylene Glycol) must be maintained at the values given in the table below. Antifreeze concentrations Antifreeze (Mono Ethylene Glycol) mixed with Nalcool 2000 Protection against Concentration -15°C 30% antifreeze -24°C 40% antifreeze -37°C 50% antifreeze -51°C 60% antifreeze

A minimum concentration of antifreeze (Mono Ethylene Glycol) of 30% is only suitable for D3500 / D3600 / C280 engines. Too high a concentration of antifreeze reduces the transfer of heat. The lifespan of the pump seals are also negatively affected. N.B.: When dosing with cooling water treatment chemicals and antifreeze, be aware that the monitoring of the coolant can only be done after the additives have complety circulated throughout the system. This can only be done after the engine is running at operating temperature and the thermostats are open (85 ºC) for 1 hour.

MORE INFORMATION Would you like more information about your cooling system or the use of the proper coolant? Please contact your Pon Power contact person. You will find them listed at www.pon-cat.com/uwcontactpersonen.

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