The Functions and Maintenance of Engine Coolant

The great importance of engine coolant to trouble-free vehicle operation is poorly understood. Maintenance managers and industry experts estimate that over 40% of a heavy-duty engine’s downtime is related to coolant system problems, virtually all of which is preventable with proper preventative maintenance! The coolant removes excess heat from the engine. Without coolant, the engine metals would quickly soften and deform, resulting in catastrophic damage. In addition, since water is corrosive to engine metals, the coolant has to contain anti-corrosive protective chemicals to prevent rust and other damage that weakens the engine parts or radiator. There are many metals to protect: aluminum, steel, cast iron, copper, brass and solder. Furthermore, the coolant must not attack the rubber hoses or gaskets in the engine. Of course, it must provide antifreeze and anti-boil protection.

Antifreeze is actually a treatment for the water that is used to cool an engine. The water is very important, as it is the primary part of the coolant that removes the heat. The antifreeze treats the water to prevent rust, corrosion, hose failures, radiator failures, liner pitting and a host of other possible problems. Fleet Charge fully formulated coolant was the first, and is still the best, diesel specific coolant that is engineered for any vehicle in a fleet. The industry has agreed that most antifreeze/coolants are formulated to be mixed half-and-half with water. This is important, because even if you live in Minneapolis or Phoenix you should use 50% antifreeze to insure that your engine is properly protected. In extremely cold climates, it is permissible to increase the antifreeze to a maximum of 70%. Most people don’t realize that above that, the freeze point actually gets warmer! The maximum antifreeze protection with Flee Charge (and other EG based antifreezes) is –86 degrees F when 70% Fleet Charge is mixed with 30% water.

General Considerations:

Fleet Charge fully formulated coolant was engineered to address the needs of virtually every light, medium or heavy duty engine in your fleet. The basic coolant recipe is simple: half Fleet Charge and half water. In most cases, local drinking water is just fine for use with Fleet Charge. (We don’t recommend well water or really hard water.) At every oil change, check the coolant to insure it is still 50/50 with a test strip or refractometer.

Light and medium-duty vehicles – Most of these engines only need to have 50/50 Fleet Charge maintained in their systems. Once a year, add 1 pint of Pencool 3000 for every four gallons of coolant capacity. The additive replenishes the inhibitors that Fleet Charge came with, and eliminates the need for annual or bi-annual coolant changes. Drain, flush (with plain water) and refill the cooling system every five years or 150,000 miles, whichever comes first.

Heavy-duty trucks – Fleet Charge offers the option of conventional or extended maintenance for heavy-duty trucks. Conventional maintenance involves filling the coolant system with 50/50 Fleet Charge. Every two months or 20,000 miles, check the system with a two-way test strip that measures freeze point and nitrite concentration. After reading the test strip, adjust the freeze point by adding Fleet Charge coolant, if necessary.  If the nitrite concentration is low, replace the coolant filter with a quality SCA-containing filter, or add liquid SCA of your choice as recommended by the vehicle manufacturer. Drain the coolant every two years or 250,000 miles when using this conventional maintenance program.

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