Diesel Engine Cooling System Maintenance | The Basics & Tips from the Experts
Did you know that an electrical short can degrade your engine’s coolant, in turn seriously damaging your engine? Or that a combustion-gas leak or air leaking into the system can also cause your diesel engine cooling system to fail? Like other forms of prevention, cooling system maintenance is a smart investment in the longevity and productivity of construction equipment.
All coolants are not the same, because the ratio of ethylene glycol to water varies. Heavy-duty coolant often also includes additives and is described as “fully formulated.” You have to know what’s in your radiator in order to retain the specific formulation. Over time, the additives are depleted and must be replenished to maintain adequate nitrite levels. On the other hand, too much nitrite or other accumulated additives can cause problems such as corrosion or decreased coolant efficiency. It’s a balancing act.
Preventing wet-sleeve cavitation
Analyzing your coolant can also help you detect wet-sleeve damage caused by cavitation, random electrical currents running through the coolant, calcium or magnesium scale that can block heat transfer or the presence of chloride that can turn iron particles into something akin to sand.
Wet-sleeve cavitation is very serious because it can cause engine failure. Under the right conditions in a wet-sleeve cooling system, the additives in your antifreeze can form a barrier between the tiny bubbles in the coolant and the engine’s sleeves. Normal vibration causes the bubbles to collapse, an event which doesn’t sound impressive but which happens with such impact it can actually pit the sleeve. Over time, these pits can develop into holes, and coolant can leak into the cylinder.
Maintenance tips from the experts
- Check the coolant at every regular service interval. It should be clear (cloudiness indicates rust) and the proper color (antifreeze variations are identifiable by color – you’re checking to be sure you aren’t running a mixture). Use a refractometer to ensure freeze/boil protection is still adequate.
- Paper test strips provide a simple way to check your antifreeze. Be sure to use strips specific to your type of coolant, and note that if the coolant is more than 60% glycol freeze-level readings may be off.
- If you’re using a fully formulated conventional antifreeze, periodically clean your system by draining, flushing and refilling it. In between, test additive levels and refresh if necessary. Coolant additives also come in different formulations, so again it’s important to know what you’ve been using, as mixing them is not advised.
As an alternate, you could simply start fresh every year, instead of following the recommended every-other-year replacement regimen. Potential downside here is that some of the chemicals in the additive formula may weaken after only 1,000 miles, leaving your diesel engine cooling system vulnerable.
- Extended-life coolants can last as long as 12,000 hours or 600,000 miles. When longer-lasting formulas also include nitrite, they’re called “nitrited organic acid technology” antifreeze, or NOAT. These formulations usually require additional “extender” at about 6,000 hours or 300,000 miles.
- To avoid problems in your diesel engine cooling system caused by random electrical currents, regularly check to be sure ground connections are secure for the batteries and starter and any add-on accessories.
- Also be sure the pressure cap and hoses are in good condition and clamps are tight, to keep air from entering the cooling system.
- Avoid using tap water to mix antifreeze. Depending on your water, this could increase risk of rust, corrosion or scale. Instead, use deionized or demineralized water.
The fundamental take-away here is consistency — in the products you use and in your cooling system maintenance procedures. That eliminates the risks that come from mixing antifreeze and/or additive formulations that don’t belong together, and it ensures reliable coolant performance. You can be sure your diesel engine cooling system is best protected against problems that could cost you dearly down the road.