The typical internal combustion engine has a water-cooled, four-stroke design using three circuits of working fluids: combustible air/fuel mixture, water based coolants usually containing glycol and motor oil used for engine lubrication. All three systems are vital and should never be allowed to intermix. But, at least one original equipment manufacturer says that more than 50% of catastrophic engine failures are caused by coolant leaks and cross-contamination. Coolant contamination of lubricating oil occurs most often when a gasket blows or the cylinder head or inlet manifold gaskets are damaged.
Engine lubricants can handle "normal" moisture levels caused by condensation due to the engine warming up and cooling down. Small of amounts of water simply evaporate away. But catastrophic failure happens when there is substantial contamination over a relatively short time. Contamination with anti-freeze involves not only the water portion, but also several other additives that were never intended to lubricate.
When mixed with motor oil, antifreeze/coolant causes a thickening of the lubricant, thereby increasing the oil viscosity and reducing oil flow to critical engine parts. This leads to boundary conditions where metals are no longer separated by a thin film of lubricants, with friction and wear resulting.
Coolant contamination in motor oil can also damage the engine by creating an acidic environment within the engine, resulting in corrosion. The protective detergents and anti-foaming agents in the motor oil become compromised, and performance is negatively impacted.
When glycol contaminates engine oil, the result is formation of what's commonly referred to as "black sludge." The gooey, thick gel restricts oil flow as it moves throughout the engine. It is common for glycol and sludge emulsions to completely block filters, which is reported to be the leading cause of premature filter failure in diesel engines.
Used oil analysis by a professional laboratory is the best way to determine if you have a coolant leak, but a visual inspection of the filter can show if sludge is beginning to form and is restricting oil from flowing properly.
If coolant contamination is found, the lubrication system must be cleaned and flushed of all contaminants before refilling. This is a long and costly procedure that must often be repeated several times before the contamination is completely removed.
Using high quality coolants and lubricants can be the best defense in preventing catastrophic engine failure. For more information, contact your FS Energy Specialist today.