Understanding Oil Contaminants

Tom Bock
October 2017

Usually this column addresses motor oil sampling. But with winter and colder weather fast approaching this may be a good time to discuss coolant sampling, transmission and differential oil sampling. Most people disregard the need to periodically analyze the other fluids that protect the engine and critical systems of a vehicle and usually don’t think about it until some major component fails.

While the motor oil will protect your engine from wear and provide lower end cooling, it is the coolant protects engine from freezing and overheating. When you take into consideration over 40% of premature engine failures are due to a coolant system problem, sampling the coolant should be part of your preventive maintenance program, especially prior to the winter.

The coolant system is typically the most neglected component of the modern diesel engines. Most people think that as long as they maintain the proper coolant levels the system will function properly. They fail to realize that chemical reactions degrade the coolant and cause metal corrosion and chemical breakdown, making the coolant ineffective and decreasing useful engine life. Coolants are formulated to prevent problems improperly maintained poor quality coolant will result in corrosion, pitting, cavitation, erosion and electrolysis, leading to premature engine failure.

A comprehensive coolant sample analysis will detect contamination, combustion gases, metal corrosion, chemical breakdown and overheating issues. Identifying these issues within the cooling system will enable you to make the necessary repairs to prevent premature engine failure. It is recommended that the coolant be sampled twice per year in April and October, to ensure proper coolant properties for protection from the elements.

The over the counter tests you can purchase at most auto stores will give you the percentage of water vs. coolant. The percentage while important will not tell you the levels of contaminates, acids, inorganic inhibitors, hardness etc. A comprehensive coolant sample analysis usually costs $65 - $125, a relatively small amount to ensure your engine does not fail prematurely and will identify potential problems the contaminants cause, allowing you to make an informed maintenance decision.

Most of the motor oil sampling kits will also provide analysis of transmission and differential oil, usually for the same cost as motor oil sample. The oils used in both the transmission and differentials are not changed as frequently as motor oil and do not undergo the same type of filtration to remove contaminants. These parts undergo heavy loads that cause wear to gears, bearings and bushings that left unchecked could result in failure of component. It is always better to utilize proactive, preventive maintenance then it is to breakdown on the side of the road somewhere.

Remember to review the analysis results and recommendations carefully before authorizing any major repairs or contact the lab to discuss further before finalizing your plan. A quick check with the experts is always a good idea before spending big bucks.

If you have any questions pertaining to coolant or oil or oil sampling please send them to [email protected][email protected] with the subject line: MOVIN OUT QUESTION