Oil Condition Monitoring - Using Oil Analysis in The Truck Fleet

By regularly analyzing engine oil, fleet managers can proactively address issues, ensuring the health and longevity of the truck fleet while minimizing downtime and maintenance costs. Here are some other uses for oil analysis for a truck fleet:

• Optimizing Oil Change Intervals: : By analyzing the condition of the oil, fleet managers can determine the optimal time to change the oil. This can prevent unnecessary oil changes, saving on maintenance costs, and ensuring that the oil is replaced only when needed.


• Monitoring Engine Wear:The analysis provides insights into the levels of wear particles in the oil. Monitoring wear trends over time helps in assessing the overall condition of the engine components, such as pistons, cylinders, and bearings.


• Contamination Detection: Engine oil analysis can identify contaminants such as dirt, coolant, fuel, or other fluids. Detecting and addressing contamination issues promptly can prevent damage to engine components and maintain overall engine efficiency.


• Fuel Dilution Assessment: : Analysis can reveal if there is an excessive amount of fuel in the oil. Fuel dilution can lead to a decrease in oil viscosity and lubricating properties, potentially causing engine damage if not addressed.


• Coolant Leak Identification: The presence of coolant in the oil may indicate a leaking coolant system. Identifying this early can prevent overheating issues and avoid extensive engine damage.


• Maximizing Engine Life: Regular oil analysis helps in extending the lifespan of engines by addressing problems early and ensuring that the engines operate with clean and well-lubricated components.


• Cost Savings: By preventing unexpected breakdowns and addressing issues proactively, fleet managers can reduce the overall maintenance and repair costs. This can lead to increased reliability and reduced downtime for the trucks.


• Compliance with Maintenance Schedules:Engine oil analysis helps ensure that the fleet is adhering to recommended maintenance schedules. This is particularly important for warranty compliance and maintaining the reliability of the fleet.


• Environmental Impact:Properly maintained engines are more fuel-efficient and produce fewer emissions. Regular oil analysis can contribute to environmentally responsible fleet management by optimizing engine performance.

Analyzing engine oil in a truck fleet can provide valuable information about the health and performance of the engines. Here are several justifications for conducting engine oil analysis in a truck fleet:

Early Detection of Issues:

Engine oil analysis can help identify potential problems and wear in the early stages. This early detection allows for timely maintenance or repairs, reducing the risk of major engine damage. Engine oil analysis in a truck fleet can reveal various issues in the early stages, allowing for timely intervention and preventing more severe problems. Here are some examples of issues that can be detected early through oil analysis:

• Abrasive Wear: Increased levels of wear particles, such as metals (iron, aluminum, etc.), in the oil may indicate abrasive wear on engine components like pistons, cylinders, or bearings. Early detection can prevent further damage and the need for costly repairs.


• Coolant Contamination: Presence of coolant in the oil can suggest a coolant leak. Early detection helps in identifying issues with the cooling system, preventing overheating and potential damage to engine components.


• Fuel Dilution: Oil analysis can detect higher-than-normal levels of fuel in the oil, which may indicate fuel dilution. This can lead to a decrease in oil viscosity and lubricating properties. Addressing this early prevents potential engine damage.


• Viscosity Changes:Monitoring changes in oil viscosity can reveal issues with oil degradation or contamination. Early detection allows for corrective action, such as changing the oil or addressing contamination sources.


• Oxidation and Thermal Breakdown: Increased levels of oxidation products in the oil may indicate thermal breakdown. Early detection of oxidation allows for corrective measures to be taken, such as adjusting operating conditions or changing the oil to prevent further degradation.


• Particle Count Analysis: Analyzing the size and distribution of wear particles can provide insights into the type of wear occurring in the engine. Different types of wear may require different maintenance actions, and early identification helps in planning appropriate interventions.


• Additive Depletion: Monitoring the levels of additives in the oil can indicate if they are depleting faster than expected. Additives play a crucial role in maintaining oil performance. Early detection allows for replenishing additives or changing the oil with a fresh supply.


• Oil Oxidation and Nitration: Increased levels of oxidation and nitration byproducts in the oil may indicate issues with oil stability. Early detection allows for adjusting operating conditions or replacing the oil to prevent further damage.


• Wear Trend Analysis: Monitoring trends in wear particle levels over time helps identify abnormal patterns. Sudden spikes in wear particles can indicate an emerging problem, allowing for prompt investigation and maintenance.

Age of Trucks:

The age of trucks and the maintenance practices employed can significantly influence the percentage of trucks experiencing engine issues. It has been our experience that new trucks (less than 2 years old, and older trucks (greater than 8 years old) will experience the greatest number of issues. The percentage of critical alarms that occur using oil analysis has a direct relationship to the type of maintenance philosophy that is employed.

• Newer Trucks: Generally, newer trucks are equipped with more advanced technology and improved design features. They may benefit from better fuel efficiency, reduced emissions, and enhanced overall performance. However, this doesn't mean they are entirely immune to issues, and proper maintenance is still crucial. We have found that at least 20% of new trucks experience cautionary to critical alarms from


• Inadequate Lubrication - the wrong grade or viscosity oil is used.
• New component defects
• Poor maintenance practices or workmanship


• Older Trucks: As trucks age, the likelihood of experiencing engine issues tends to increase. Over time, components can wear out, and the risk of mechanical failures rises. Aging trucks may also have outdated technology and may be more prone to issues related to wear and tear. There is a direct relationship for cautionary to severe issues being identified through oil analysis with the age of the engine. A common average is that for every 50,000 miles put on an engine, not providing proper maintenance will produce an increase of 15% cautionary or severe alarms on the engine. The common source of these issues resides with:


• Fuel dilution due to faulty injectors, Idling in cold weather, and improper timing
• Non-OEM Spare Part Material Defects
• Improper Maintenance Practices
• Oil Loss due to leaks or extended use creates wear and overheating.
• Over Speed / Overload
• Time Dependent - This can occur at end of equipment/component life cycle; thermal or fatigue cycles

Maintenance Practices:

• Regular Maintenance: Trucks that undergo regular oil analysis and preventive maintenance are less likely to experience engine issues. Routine oil sampling and oil changes, filter replacements, and thorough inspections can identify and address potential problems before they escalate.


• Adherence to Manufacturer Recommendations: Following the manufacturer's recommended maintenance schedule is essential. This includes not only oil changes but also checks on critical components, fluid levels, and other aspects of the engine and vehicle. Failure to adhere to these recommendations can increase the risk of engine issues.


• Quality of Maintenance: The quality of maintenance practices matters. If maintenance is performed haphazardly or by inexperienced technicians, it may lead to oversight or inadequate care for critical components, increasing the likelihood of engine issues.


• Proactive Repairs: Identifying and addressing minor issues during routine maintenance can prevent them from evolving into major problems. Proactive repairs and addressing potential concerns early contribute to reducing the overall percentage of trucks experiencing engine issues.


• Use of Genuine Parts and Fluids:Using genuine parts and recommended fluids during maintenance is crucial. Substituting with inferior quality parts or fluids can lead to accelerated wear and may contribute to engine problems.


• Technology Integration: Some fleet managers adopt advanced technologies, such as telematics and predictive maintenance systems, to monitor the health of the trucks in real-time. These technologies can help in predicting and preventing potential engine issues before they occur.

The age of trucks and the maintenance practices implemented play integral roles in determining the percentage of trucks experiencing engine issues. Older trucks require more meticulous maintenance, and the likelihood of issues increases with age. Regular, proactive, and high-quality maintenance practices are key to minimizing engine problems and ensuring the longevity and reliability of a truck fleet.

Using Oil Analysis

The specific used oil analysis tests you should run on used diesel engine oil will depend on several factors, including:

• Engine type and age: Different engine types have different wear patterns and require different tests to monitor their health. Older engines may also require additional tests to check for specific issues.


• Oil type and viscosity: Synthetic oils and high-viscosity oils may require different tests than conventional oils or lower-viscosity oils.


• Operating conditions: Engines that are operated under severe conditions, such as high loads, high temperatures, or dusty environments, may require more frequent OCM and additional tests.


• Maintenance history: If the engine has recently had any maintenance work done, such as an oil change or a filter change, you may want to run additional tests to monitor the effectiveness of the work.

Here are some of the most common tests for diesel engine oil:

• Viscosity:This test measures the thickness of the oil at different temperatures. It is important to monitor viscosity because it can affect the engine's lubrication and cooling performance.


• Total Base Number (TBN): This test measures the oil's ability to neutralize acids that are produced during combustion. TBN will decrease over time as the oil is used, and it is important to change the oil before the TBN reaches zero.


• Total Acid Number (TAN): This test measures the amount of acid that is present in the oil. TAN will increase over time as the oil is used, and it is important to change the oil before the TAN reaches a critical level.


• Wear metals: These tests measure the amount of metals, such as iron, aluminum, and copper, that are present in the oil. The presence of wear metals can indicate that there is internal engine wear.


• Soot:This test measures the amount of soot that is present in the oil. Soot can come from incomplete combustion and can contribute to engine wear and oil sludge formation.


• Fuel dilution: This test measures the amount of fuel that is present in the oil. Fuel dilution can occur if the fuel injectors are leaking or if the engine is not operating properly.


• Water content: This test measures the amount of water that is present in the oil. Water can come from condensation or from leaks, and it can lead to corrosion and other problems.

In addition to these common tests, there are many other tests that can be run, depending on your specific needs. Some of these tests include:

• Oxidation:This test measures the amount of oil that has been oxidized by heat and air. Oxidation can lead to oil thickening and sludge formation.


• Nitration: This test measures the amount of oil that has been nitrated by high temperatures. Nitration can lead to increased wear and corrosion.


• Glycol: This test measures the amount of glycol that is present in the oil. Glycol can come from antifreeze leaks and can lead to oil sludge formation.


• Phosphorus: This test measures the amount of phosphorus that is present in the oil. Phosphorus is an additive that is used to prevent wear, but too much phosphorus can lead to problems with catalytic converters.

Choosing the right used oil analysis tests for truck transmission oil can be nuanced and depends on several factors, including:

Transmission type:

• Manual:Focus on wear metals, viscosity, water content, and contamination (such as coolant from leaks).
• Automatic:Include tests for viscosity, oxidation, friction modifier effectiveness, wear metals, water content, and contamination (including clutch material debris).

Operating conditions:

• Heavy loads, frequent shifting, high temperatures: Consider additional tests for oxidation and friction modifier depletion.
• Dusty environments:Prioritize wear metal analysis and contaminant detection.

Maintenance history:

• Recent oil change or repairs:Monitor wear metals and contaminant levels to assess effectiveness.

Basic tests:

• Viscosity: Monitors lubrication and cooling performance.
• Wear metals:Detects internal wear (iron, aluminum, copper).
• Water content: Checks for leaks or condensation (can lead to corrosion).

Additional tests for automatics:

• Total Acid Number (TAN):Measures oil's ability to neutralize acids from combustion (affects friction modifiers).
• Total Base Number (TBN): Checks remaining acid-neutralizing capacity.
• Friction Modifier Analysis: Assesses effectiveness of clutch engagement and smooth shifting.
• Soot:Indicates incomplete combustion and potential clutch wear.

Optional tests:

• Oxidation:Monitors oil degradation from heat and air (affects lubrication and seal durability).
• Glycol:Detects antifreeze leaks (can cause foaming and lubrication issues).
• Silicon:Indicates external contamination (dirt, sand).

Choosing the right test package:

• Consult with a qualified lab based on your transmission type, operating conditions, and needs.
• Consider starting with a basic package and adding tests based on specific concerns or operating severity.
• Regular analysis allows tracking trends and detecting potential issues early, preventing costly repairs.

Sometimes, a truck will have a hydraulic system. Here are some considerations:

Hydraulic system type:

• Open or closed system: Closed systems generally experience less contamination, while open systems might need additional tests for environmental ingress.


• Operating pressure and temperature: Higher pressures and temperatures increase stress on the oil and suggest potentially relevant tests.


• Fluid type:Mineral, synthetic, or bio-based fluids may require different tests based on their properties and breakdown patterns.

Specific concerns:

• Wear: Analyze wear metals like iron, aluminum, and copper to detect internal component wear
• Contamination:Look for dirt, water, glycol (from leaks), or other foreign materials degrading performance.
• Oxidation:Assess oil degradation from heat and air exposure, impacting viscosity and seal compatibility.
• Acidification: Measure Total Acid Number (TAN) to monitor acid buildup from oxidation and combustion products, affecting component corrosion.
• Viscosity change:Monitor how viscosity deviates from the specified range, impacting lubrication and pump efficiency

Common OCM tests for hydraulic oil:

• Basic package: Viscosity, wear metals, particle count, water content.
• Comprehensive package: Includes basic tests plus acid number (TAN), oxidation measurement, and potential analysis for specific contaminants like glycol or silicon.

Additional tests to consider:

• Fourier Transform Infrared Spectroscopy (FTIR): Identifies oil degradation products and potential contaminants.
• Elemental Spectroscopy: Provides detailed information about specific wear metals and their sources.
• Particle Count & Analysis:Analyzes particle size and type to diagnose specific wear modes and contamination sources.

About the Author

Michael D. Holloway is a veteran in the industry with 38 years of experience including product research and development, application engineering, program management, technical sales and marketing. He has been involved in the development and certification preparation instruction for lubrication, maintenance, reliability, quality, and safety. He is considered a subject matter expert in condition-based maintenance, reliability, lubrication, oil analysis, wear debris analysis, failure analysis, tribology, and technical writing. Holloway has a patent, earned 4 university degrees, published 11 books, and holds 16 professional certifications. He can be reached at michael.holloway@sgs.com

Michael D. Holloway
Global Technical Manager | SGS