Fleet Management News & Business Info | Commercial Carrier Journal
Issue link: http://read.dmtmag.com/i/284466
32 COMMERCIAL CARRIER JOURNAL | APRIL 2014 in focus: COOLANTS AND ADDITIVES H eavy-duty engine coolants perform a tough job in a tough environment, so con- sistently having quality cooling system protection is a no-brainer for fleets. Unfortunately, the evolution of diesel engines and the different types of cool- ants required for specific power units have led to some confusion as to what types of coolants and additives are needed and when to add them. According to Colin Dilley, director of technology for Prestone, coolants perform four basic functions by: s 0ROVIDING EFlCIENT HEAT TRANSFER TO control critical metal temperatures; s )NCREASING THE COOLING INDEX TO help prevent boilover and overheating failures; s 'IVING FREEZING PROTECTION TO PREVENT FREEZEUPS OR NONSTARTS IN LOW temperatures; and s 0ROVIDING EFFECTIVE INHIBITION OF corrosion for all cooling system metals. )N ADDITION TO PROTECTING THE ENGINE FROM OVERHEATING ANTIFREEZECOOLANTS also help prevent the cooling system from DEGRADING IN VARIOUS OTHER WAYS 'LYCOL n the basic chemical component of engine COOLANTS n AND WATER ARE NATURALLY CORRO- sive, and over time, they will erode and destroy vital cooling system components. To combat this, coolant manufac- TURERS ADD DIFFERENT INORGANIC AND or organic salts and other chemicals known as corrosion inhibitors, Dilley says. Some common ones are: s 3ILICATESILICONE WHICH PROTECTS aluminum components; s 4RIAZOLESTHIAZOLES WHICH PROTECT copper and brass components; s Sodium molybdate, which protects ferrous metals, cast iron and steel; s Nitrate, which protects against pitting and crevice attack in alumi- num components; s Nitrite, which prevents cylin- der-liner pitting in cast-iron components; s Organic acids that replace other inhibitors; and s !NTIFOAM WHICH MINIMIZES FOAMING WHEN COOLANT IS MIXED with water. All coolants aren't alike Most conventional LOWSILICATE ANTIFREEZE coolants come prefor- mulated with a pre- charge of additives to protect cooling systems against corrosion, cavita- TION LINER PITTING FREEZING and boilover, among other problems. Dilley says these coolants AND THEIR PREMIXED ADDITIVE PACKAG- ES ARE DESIGNED FOR EXTENDED SERVICE intervals and generally do not require REPLENISHING UNTIL THE VEHICLES lRST MAINTENANCE INTERVAL n TYPICALLY ABOUT MILES n ALTHOUGH mEETS SHOULD REFER TO SPECIlC /%- GUIDELINES TO ensure warranty requirements. Complicating matters is that addi- tional coolant types are required by en- gine manufacturers to ensure warranty compliance. These include hybrid or- ganic acid technology (HOAT) blends AND EXTENDED LIFE COOLANTS USING NITRIT- ed organic acid technology (NOAT), which do not require refortifying until 300,000 miles or 6,000 engine hours to achieve their full 600,000 miles or 12,000 engine hours of service life. -IXING DIFFERENT COOLANT TYPES NEVER is recommended, as the offsetting chemical makeups of each type will cancel each other out, leading to severe- ly degraded protection, Dilley says. Over time, the additives in both conventional and HOAT coolants BY JACK ROBERTS Know your coolants The Technology and Maintenance Council's definition of the different heavy-duty coolant types and their basic characteristics: ANTIFREEZE/COOLANT TYPE TMC SPEC SUGGESTED COLOR CODE TMC A, conventional low silicate RP 302A Green TMC B, fully formulated ethylene glycol RP 329 Purple or Pink TMC C, fully formulated propylene glycol RP 330 Blue TMC D, organic acid technology (OAT) Per OEM specs Red Source: Technology and Maintenance Council Cutting down confusion on coolants Making sense of the additives and acronyms on the market today