Tech Tips

Coolant Cues

Cooling systems are too often overlooked until problems crop up. Spending a little time monitoring coolant level and quality can pay huge dividends by reducing downtime and extending engine life. Simple, routine maintenance can prevent costly repairs due to cracked liners and engine blocks, pitting, and scale build-up.

Proper coolant formulation is critical to prolonging engine life. Coolant mixtures consist of three components: the basic antifreeze solution, which should be a low-silicate, fully formulated product; distilled or deionized water; and specially formulated supplemental coolant additives (SCAs) that protect engine parts from corrosion. Most antifreeze solutions are based on either ethylene glycol or propylene glycol, which have similar performance characteristics. Ethylene glycol solutions usually cost less.

50/50 antifreeze/water mixture is optimal, except in extremely cold climates where a mixture with 60 percent antifreeze will provide additional protection against freezing. It's recommended that you use only deionized, distilled or demineralized water. Unsoftened tap water, which is either too acidic or too alkaline, can promote corrosion and scale build-up.

Replace and recharge coolant mixtures according to manufacturers' recommendations. Traditional coolants should be replaced every two years, 240,000 miles or 3,000 hours of operation, whichever comes first. SCAs, which contain conditioners and inhibitors, must be replenished more frequently, either by using pre-charged coolant filters or by adding new supplemental coolant additive in concentrated liquid form. Only SCAs recommended by the coolant manufacturer should be used. Adding the correct SCA at the scheduled interval is one of the most important aspects of engine maintenance. Failing to maintain the proper coolant chemistry can damage an engine in as little as 15,000 miles.

Clean coolant systems whenever there is evidence of leaking seals, malfunctioning cooling fans, high oil temperatures or sticking thermostats. Alkaline cleaners are best suited for removing gelled silicate, while acid cleaners should be used to remove rust and scale. Both types of cleaners will remove, oil, grease and solder. Each time a chemical cleaner is used, the coolant system should be thoroughly flushed twice with clean water before new coolant is added.

JX Enterprises also recommends the following for proper cooling system maintenance:

• Check coolant level each day during the pre-trip inspection.
• Test the coolant's effectiveness every service interval or whenever there is evidence of corrosion or leaking seals.
• Don't mix blends. Manufacturers develop products to create an optimum balance of inhibitors. Mixing antifreezes not only reduces that effectiveness, but can create a chemical reaction that could damage the engine.
• Good record keeping is critical. Maintenance records should include coolant hours, test results, coolant top-off amounts, freeze point, antifreeze concentrations and any information about the addition of SCAs.