How important could it be to get a detailed view of things happening within a machine component? Indeed, very important. You can only do this by performing a routine activity called Engine Oil Analysis. This activity particularly aims to analyze the oil’s properties, contamination, and wear debris.
Engine oil analysis is a popular method used throughout a wide range of industries involving the use of mechanical equipment. This program testifies the performance of your machine whether it is up to the expectations or not. Taking immediate action is way easier when any unwanted condition is observed. This will help you fix the major issue and mitigate any kind of upcoming failure.
The automobile owners or mechanics are one of the top priority target audiences we are writing this article for. This guide for engine oil analysis covers its significance for passenger vehicles as well. Like all other machines, a vehicle also requires proper and routine maintenance. The more you are good at maintenance, the more you can relax about its performance. At least in terms of its basic functions not getting suddenly ceased. And no maintenance is possible to think without paying attention to the oil analysis activity?
The Reasons To Perform An Engine Oil Analysis
One of the most obvious reasons for performing an engine oil analysis is to understand the machine’s condition based on the diagnosis report of the oil’s condition from its sample taken from the respective machine.
To realize the concept better, “Oil analysis for machines” is similar to “Blood analysis for the human body”. In the case of a blood test, the doctor pulls a blood sample which is then made to go through a lineup of diagnosis machines. The diagnosis results are then carefully studied, and a final report is delivered based on the doctor’s knowledge, research, and detailed observation of the patient’s condition.
And the same thing happens with engine oil analysis as well. The oil samples undergo an elaborate diagnosis procedure to yield the result. Here, this is subjected to further interpretation by knowledgeable lab personnel about the important details regarding the oil and mainly the machine. These details are:
- The environmental condition of the machine (the highest state of temperature, humidity, vibration, etc.)
- Which of the originating components like the pump, steam turbine, etc. are currently in use
- The permanent ID of the component and the sample’s specific port location
- The procedures involved in sampling can confirm a continuously representative sample
- The number of occurrences regarding oil change or the addition of makeup oil and also its quantity since the previous oil change.
- Sample component’s total running time since its purchase or renewal
- The oil’s total runtime from its previous change
- Any important activity that could have an impact due to the lubricant change
Interpretation of an oily analysis with untrained personnel can be upsetting. This is a rather sophisticated and expensive method. It takes millions of dollars spent by different industrial plants to commercials labs for having them perform an engine oil analysis on new and old samples. However, it’s sad that most of the plant personnel are not qualified enough to interpret the lab reports.
Different Categories of Engine Oil Analysis
We will be looking at the different categories of engine oil analysis, mainly three: fluid properties, wear debris, and contamination.
This oil analysis aims to diagnose the current condition of the oil’s physical and chemical properties and also define the Remaining Useful Life (RUL). Through this analysis, you will get the following answers –
- Is the sample identical to the specified oil?
- How good is this oil to use?
- Are the right additives’ state active?
- What about the depletion of the additives?
- Did the viscosity shift from the expected viscosity? If yes, why?
- What is the RUL of the oil?
With regards to detecting the proximity of harmful contaminants and identifying their sources (whether internal or external), this form of oil analysis will answer questions such as:
- Does the oil look to be clean?
- What kinds of contaminants are found in the oil?
- Where do these contaminants originate?
- Are there signs indicating the presence of other lubricants?
- Is there any indication of internal engine oil leakage?
This method of oil analysis is aimed to determine whether any particles resulting from mechanical wear or surface degradation is present or not. If so, the identification of the particles is made through this analysis. Besides, you could find answers to questions like:
- Is the degradation of the machine normal?
- Did the machine produce wear debris?
- Which internal component is likely to be responsible for originating the wear?
- What could be the reason for wear mode and cause?
- Is the wear condition severe?
Finding the answers to these questions will narrow down your list of actions to keep your oil and machine healthy.
Engine Oil Analysis Is Rarely Performed On Passenger Vehicles
For the following reasons, the oil analysis seems to be rarely performed on the diesel engine oil of passenger vehicles.
- One of the major reasons is the lack of anticipation regarding the potential failure of the engine during ownership. People generally use a new car for around five to 10 years. This limited period use and reliance on the insurance or warranty covering potential failures makes them uninterested in going through such a sophisticated procedure as oil analysis.
- The next thing that stops them from going through this maintenance process is the myth that changing the oil and the oil filter is enough to maintain the car’s engine. However, they don’t realize the oil analysis cost is not more than what it takes to change engine oil.
- Another thing is the false sense of security that they seem to be growing because of the onboard “oil life” indicator in their vehicles which presents real-time feedback of the engine’s oil condition that doesn’t show the whole picture.
- Even those who understand the benefits of engine oil analysis cannot make the best out of it as they are unaware of the convenient and effective method of collecting an oil sample on a passenger vehicle. Besides, there is also a lack of good locations to take an oil sample.
These are the most notable reasons why the oil analysis market for passenger vehicles is so small. However, it should not remain the same, especially considering its ability to provide information regarding the contamination and wear debris presented in the oil. But unfortunately, this goes unnoticed; taking action according to this could certainly make the engine condition better.
But regarding the industrial machinery, we see they realize the fact that the potential indication of any abnormal contamination issue or rapid degradation of oil causing a menacing machine failure is the primary basis of the sampling frequency of oil analysis. This is a unique way to get an early assumption long before the external symptoms come into play. In the case of industrial machinery, an oil sample is collected every certain number of weeks/months. The evaluation is done using a preset of routine tests. It is important the extension of the drain interval, provided that the cost is for oil extraction and replenishment when it reaches its tolerance limit. And also provided the fact that pulling a sample does not take much effort with a sample port being installed. Hence, monitoring machine condition through engine oil analysis is important regardless of its cost simply because machines are critical.
While normal passenger vehicles are not designed for oil sampling during operation. The ideal sampling location is supposed to be on the pressure line between the pump and filter of the wet-pump system. But this is a rather improbable location; as a result, the sampling is done at the drain port while a drain-and-fill or by using the method of drop-tube vacuum sampling. Remember to use the best practices while continuing with these two locations.
In the case of passenger vehicles, the engine’s most feasible sampling interval would be just before the routine drain interval because oil drains are typically more frequent in this kind of vehicle than in other machinery.
The person interpreting the oil analysis data has a chance to efficiently forecast the data points if the normalization of sampling interval time relative to the last oil change is done. It is a pretty handy opportunity as it can determine the current duration of the drain interval while yielding different information on the engine’s health.
Engine Oil Analysis Tests
As we said earlier, engine oil analysis focuses on obtaining some important information about the properties, contaminants, and wear debris. The reports may focus on obtaining one or multiple points of specific information. The oil tests recommended for standard equipment is considered to be the normal routine tests. These usual routine engine oil tests include viscosity, acid/base number testing, Fourier transform infrared (FTIR), elemental analysis (spectroscopy ), moisture/water level analysis, particle counting, demography, and ferrous density.
A viscosity test measures the fluid’s resistance against the flow and shear. It is one of the oil’s most important properties. The film thickness separating the relatively moving mechanical surface is created due to this property of the fluid. The formulation of the engine oil is made to match a specific viscosity.
The change in viscosity means the oil may not be able to protect the surface of the engine. It also indicates oil’s chemical degradation or its contamination with substances like water, glycol, or fuel. However, it needs further tests and investigation, even if diagnosed positive.
Acid Number/Base Number
Acid/base number tests are almost similar to the last one. But this one is used for interpreting other lubricants and contamination. The acid number test in oil analysis refers to the acid concentration in the respective oil. On the other hand, the base number test signifies the reserved quantity of alkalinity in the oil. The volume(in mg) of potassium hydroxide(base) that is used to neutralize the acids in 1 gram of acids indicates the base number. Acid number testing is done on non-crankcase oils, while base number testing is mainly used for over-based crankcase oils.
Now, the question is how this oil test can help you determine the problems with your engine. The extremely low or high acid numbers could be the outcome of oil oxidation, meaning the presence of a wrong lubricant or additive deficiency. On the other hand, an extremely low base number can refer to the presence of any inappropriate lubricant, contamination from internal leakage, engine blow-by conditions, excessive heat, or oil oxidation from the oil drain intervals.
FTIR is a sophisticated method conducted to determine the overall oil’s health, including its several parameters, including contaminants like soot, fuel, water, and glycol. And also oil degradation by-products like oxides, sulfates, and nitrates; finally, the presence of additives like zinc dialkyl dithiophosphate (ZDDP) and phenols. This has the unique technology to observe constituents in the sample at its basic molecular level. Nevertheless, the test can review a broad spectrum for analysis, but the accuracy may be hampered in that case.
Elemental Analysis is another important and sophisticated method like FITR. The difference is that it observes the oil at the elemental level to provide all its details rather than observing its constituents at the molecular level. This analysis, based on the laws of Atomic Emission Spectroscopy (AES), is also known as wear metal analysis as it detects the concentration of wear metals, different contaminants, or other additive elements in the oil. Two commonly available atomic emission spectroscopies are the rotating disc electrode (RDE) and the inductively coupled plasma (ICP).
The significance of this test can be realized after having been trended with the engine’s reference sample or its history of samples. With the increase and decrease of its elemental concentrations, the contamination level seems to be increasing, or a depletion seems to be formulating in additives within the oil.
As the name suggests, this test measures the particle’s size and quantity within the oil. To assess these data, different techniques are used. However, these techniques need to be designated under the ISO 4406:99 standards. This standard means there are three numbers distinct by a forward slash indicating a range number that corresponds to the particle counts of those with a size greater than 4, 6, and 14 microns.
The results obtained from particle counting can report things like the inefficiency of the oil filter or the intake air filter. For instance, when the oil filter has cracked, the contamination removal may get hampered, allowing them to inject the engine oil continually.
Water moisture content within an oil sample is measured using the Karl Fischer titration test. The measurement result is reported in parts per million (ppm), meaning the amount of water involved in the oil. This is often shown in percentage; all three forms of the water are measured: its dissolved form, emulsified form, and free form.
This test is important because the water in oil is something you need to be concerned about as it may cause rapid oil degradation and a corrosive reaction to iron and steel surfaces. If any abnormal quantity is observed, the sources need to be investigated. Most of the time, these sources seem to be the oil cooler, highly moisturized environment, or improper running conditions.
The ferrous density analysis is conducted to determine whether the level of ferrous wear particles has increased or not in the oil sample. This will help to observe if the wear debris has reached an abnormal level; if it has, immediate actions must be taken. Otherwise, a potential failure of the engine will be on the cards. The increased level of wear debris also indicates that the depletion of mechanical wear in the engine is already started.
Poor lubrication because of the change in the oil properties, change in mechanical ineffectiveness, or change in operating conditions could be the root cause of such a problem.
When wear debris is observed at abnormal levels, additional techniques such as Ferrography are used to check it from a closer distance to find out its root cause and severity level. This is a microscopic review of wear debris particles that includes a number of its characterizations, such as the general shape, color, and size. Some advanced characterization includes reflectivity, markings, concentrations, and edge details.
The origin and the mode of these wear particles’ production can be known from the results of this test. It can help to identify the components from which the wear particles originated and the wear mode by which the particle was produced. Thereby, you would come to know the severity of the problem and what call-to-actions are in such cases.
Interpreting Engine Oil Analysis Reports
If you are wondering about the interpretation of the engine oil analysis report and whether it is too complicated or not, we are here to help you interpret it even if you are a layman.
To give you a breakdown of the overall oil analysis report, you will find out that the report is divided into four sections such as Sections A, B, C, and D. Each of these four sections contains valuable information to give you a complete insight into the oil’s and eventually the machine’s condition.
We have given details of each of the sections below:
The most important thing to check on an oil analysis report is the information about the followings –
- Customer Information: It is an obvious part that contains the customer information on behalf of the oil analysis.
- Originating Pieces of Equipment: Getting to know the piece of equipment used for oil sampling is very much important. The reason is, that it has an impact on the capability of identifying the potential sources of the measured metrics. For instance, such a piece of equipment can provide you with a report on wear particles with specific internal components.
- Lubricant: The information on lubricant can help you get a baseline for different parameters. Among them, the most common ones are the expected viscosity grade, acid/base number, and active additives. This information may seem simple to get, but unfortunately, it is often overlooked or forgotten in the oil sample identification label/request form.
The next section of the oil analysis report provides information on the elemental analysis or FTIR analysis. With this information, you will be able to identify if there is any contamination, additives, and wear metals present in the oil, measured in parts per million (ppm).
The likely presence of contamination particles like potassium, silicon, or sodium is indicated by spikes in this section. For example, the spike indicating a rise in silicon or aluminum could mean that dirt/dust is entering in oil from any external sources, as a result, the three-body abrasion occurs in the machine causing the increase of wear debris like iron, aluminum, and nickel.
We will now help you understand the spikes in wear metals better. It gives you an idea about the internal components experiencing wear. Remember to take an appropriate and continuous frequency for trend analysis.
When the elemental data is associated with contaminants and wear metals, the alarms are set for upward trends. While alarms for downward trends are set for elemental data concerning the additives.
This section of the oil analysis report is divided into three subsections. The first one contains the previously identified sample information such as oil manufacturer, oil brand, oil viscosity grade and in-service time, and whether a change in car engine oil has been made.
Then it has the “physical tests” sub-section. It provides details on viscosity at both 40 degrees and 100 degrees Celsius, the viscosity index, and water/moisture percentage/ppm in oil. Regarding the amount of water, the standard alarm limit is considered between 50 to 300 ppm.
Finally, the “additional tests” subsection presents two final tests: acid number and particle count/distribution. A reference value and a past analysis trend are needed to analyze the acid number. A rapid increase in acid number may indicate when the oil is oxidizing rapidly and needs to be changed.
Expectedly, the last section of the report contains the results obtained after the test and also the recommendations based on the results. The lab personnel generates these recommendations manually based on the customer’s information and lab data. If the customer’s information is not collected properly, then a known person to the respective machine should be involved in providing any recommendation or explanation. However, no explanation is absolute, and further investigation should be conducted to find the root cause or exceed the limit. Additionally, graphical representations can be obtained along with raw data to illustrate the notable trends of the observations.
We will discuss the overall understanding of all the interpretation sections that take us to a call for action based on the recommendations.
To help you as a layman, the report will contain an identifier at the top indicating if the overall results are positive, reportable, unacceptable, or severe. This can also be color-coded.
You may have found the raw data the most confusing. To get an idea about what these data mean, you can refer to the ‘Engine Oil Test’ section to get an idea about the data related to the different tests like viscosity, acid/base number, moisture/water contamination, and elemental data, etc. With proper training and good practices, you may come up with interpreting these reports, even being a layman, to reach your reliability goals.
Things To Consider While Reviewing An Engine Oil Analysis Report
Usually, the results and recommendations of an engine oil analysis report come in a summarized section written in layman’s words. The laboratory comes up with the report without seeing and assessing the machine, meaning that the recommendation made is rather generic and not tailored precisely to an individual one. So, it is up to the plant personnel receiving the lab report to take actions based on the report and also based on the actual circumstance of the machine. its performance, and the performance of the oil and other lubricants.
Now, if you’re wondering how you can contribute while reviewing any oil analysis report, below we’ve got some suggestions for you.
- Check the accuracy by reading and verifying the data on the oil type and also on the machine type.
- Make sure that reference data is seen for new oils and that the data trend is understandable.
- Verify whether the viscosity is correctly measured or not.
- Check and compare the elemental wear data with the trended and reference data.
- Using a wear debris atlas for matching elements to the source is recommended.
- Do as above for the elemental additive data.
- Do as above for the elemental contamination data as well.
- Verify and compare the moisture or water levels to the trended and reference data.
- Check the acid and base number and compare it to the trended and reference data.
- Also, check other analyzed data like the FTIR oxidation levels, demulsibility, flashpoint, and analytical demography.
- Verify and compare whether any groups of data are going towards unacceptable levels or not and justify them according to the trend.
- Compare the results and recommendations of an oil analysis report with the known data and information.
- Review the alarm limits to adjust them according to the new information.
The Best Engine Oil Analysis Lab
Many engine oil analysis labs are available with varied capabilities and specialties. They focus on specific types of lubricants like engine oil more than industrial lubricants like turbine oil or circulating oil. Most of them go through the standard array of testing to provide the necessary information and data based on which actions can be taken.
Considering all the variables, it’s almost impossible to come up with a single name for the best engine oil analysis lab. To put it simply, we recommend you go to an oil analysis lab with a reputation for delivering quality data at a reasonable price and time.
Getting into an honest dialogue with the lab authorities about their core competencies will give you a better idea about them. Provide them with the necessary information and type of test you want them to perform. If they seem to be competent to meet your specifications and also offer a good turnaround time and cost, you could better go ahead with them.
Getting A Lab Near You
The geographic location for the engine oil analysis is important but not the primary concern. The quality of the data, turnaround time and the cost should be your main concern. It doesn’t matter if you may have to contact a lab far from you to meet these factors. Look for ISO-accredited laboratories that participate in the ASTM Crosscheck Program. This will give insight into the usefulness of the data coming from the lab.
However, having a lab nearby under the above-mentioned provisions is certainly beneficial as it would allow for regular audits provided the sample are hand-delivered to the lab. Besides, paying a visit to watch the facilities and analysis by yourself will be easier. Another plus is the saving of shipping costs. So, getting a lab near you could be best only if it provides quality data within a reasonable time and cost.
Engine Oil Analysis Sampling Kit
To get a sample for engine oil analysis, you need an oil analysis kit that includes everything for obtaining a representative sample from its originating piece of equipment. Most of the time, the lab to perform the engine oil analysis will provide the kit as a part of their service. This kit should contain disposable tubing, a vessel used for mailing it back, a sample label, and a sample bottle.
The cleanliness of the bottle in the kit should be verified first. Remember to keep track of all the tools supposed to be included in the kit. Some tools often seem missing, like the vacuum sampling pump, the purge bottle for flushing, and the adapter attaching to the sample port. These are the items to keep in your internal kit.
An engine oil analysis sampling kit comes with equipment used for onsite testing of new and in-service oils. These kits can provide important data on different parameters such as viscosity, acid/base number, moisture level, particle count and contamination, and wear debris. Before using them in the plant, all the lubricants must undergo these tests and lab analysis.
The oil analysis kit is extremely efficient in revealing the equipment’s condition and the lubricant as it utilizes the result inspection and other condition-based maintenance technologies (CBM). Every kit must be stored in the lube room and include testing devices such as the Vintage, test strips for acid number/base number, the tester for calcium-hydroxide, water content, and the patch test kit.
Determining The Right Engine Oil Sampling Frequency
Determining the right frequency for taking an oil sample is a critical decision in the oil analysis program. However, the average frequency for a routine sample range from two weeks to three months. Here, we will not recommend anything for any specific turbine but rather present a general recommendation that can be applied to any machine.
The optimal sampling frequency for an application should be determined according to the reliability objectives. To set the objectives, you should ask a few sets of questions; out of these sets, the first set would be about the cost of the process, which is as follows:
- How costly could it be for me if any sudden failure of the machine occurs?
- Is there any safety risk correlated with a failure?
- How much do I need to invest in forecasting any kind of failure 24 hours, 1 week, and 1 month earlier?
We would put the summary of the answers to these questions as follows:
The price you are ready to invest in is the threshold point in all circumstances. The success of the failure prediction will determine how much you could invest, particularly for oil analysis. However, oil analysis is not an absolute solution for predicting any failure, and there are more condition monitoring strategies for oil analysis. So you need to consider the fact before investing up to that threshold point. For instance, if you have a threshold of $40,000 for the whole process, it would be wise to invest no more than $5,000 in an oil analysis program to predict machine failure. You should maintain this proportion for whatever the cost is. If you consider the safety risk that may happen due to component failure, the overall cost would be much more and may exceed your initial threshold.
Now the next set of questions should be asked to account for the environment, failure development period, failure history, type of component, the age of components, etc. These questions can be like the following ones –
- Is it likely for internal lubrication areas of the machine to get exposed to any kind of contamination?
- How recently has the machine been installed, or is it approaching its lifetime?
- How quickly can a catastrophic failure due to a known root cause happen?
A failure prediction using the oil analysis method allows you to observe the failure’s root cause or symptoms within the failure development period (FDP). The FDP is known as the time between the failure’s inception. It means the period from when the wear debris is produced the first time to the time when failure results start to show up. Throughout the progress of the failure, the detectability inversely increases the potential savings from remediation. So, the remediation costs (due to an impending failure) would remain lower only if the sampling and analysis occur early in the FDP.
The FDP could range anywhere between a few months to a few hours. Apart from this range, sampling it too often or too late is not recommended at all. However, it may fluctuate if the risk profile changes.
These questions mentioned above will help you determine the right sampling frequency. They can help you estimate the machine criticality factor (the consequences of failure) and also the failure occurrence factor (most likely reasons causing the failure). Using a risk matrix for calculation, the resulting overall machine criticality can provide the right sampling frequency.
The Best Engine Oil Sample Bottles
Oil sampling should be done properly to have an effective oil analysis program. This program could not go further without the right representative sample. Getting an ultraclean sample bottle for the analysis program is the best option as it becomes easy to inspect a clean one.
The size of the sample bottle depends on the type of sample fluid and also on the number and types of tests to be carried out. For the oil analysis program, the ideal bottle size for the oil sample is 100- or 120- milliliter (ml). For an advanced testing program, a bottle size has to be 200 milliliters or more.
A larger sample bottle might be required when testing hydraulic fluid such as aviation hydraulic fluid. The smaller sample bottles can also be used in the case of other applications.
When choosing an oil sample bottle, the laboratory requirements should be kept in mind, and also check whether they have any recommended sample bottle. You also need to find out if the bottles are meant for testing, as per the ISO 3722 standard. Finally, make sure the sample bottle meets the cleanliness requirements.
Regarding the cleanliness of the oil sample bottle, there are different options available. Most of the oil testing equipment can detect the difference between ISO clean, super clean, and ultraclean bottles. It is defined as particle count respective to 10 microns per milliliter. For clean, it is 100 particles greater than 10 microns per milliliter; for super clean, it is 10 particles greater than 10 microns per milliliter; and finally, for ultraclean, it is 1 particle greater than 10 microns per milliliter.
Expectedly, the super clean and ultraclean bottles are more expensive, and they should be used when additional particles could change the recommendations for maintenance.
Consistency should be maintained regarding the equipment and the cleanliness of the bottle. For example, an oil sample collected with a clean (100 particles) bottle means that the next sample should also be collected with the same bottle type.
Remember, the tools used to extract an oil sample should not hamper the sample quality, and it should also be clean, easy to use, sturdy and reasonable. With the right bottle type and cleanliness level, you can ensure that the right representative sample is obtained.
Monitor Filtered Oil
At last, we would be emphasizing the need to monitor filtered oil; further analysis is required to verify its level of cleanliness. Oil sampling can be broken into three categories to show the best practices for soil sampling. These are as follows –
Offline Sampling: The first category is offline sampling, where a sample is pulled from a mini-mess, drop tube, or drain valve. This analysis can be done in-house or sent for laboratory analysis. Good data will be obtained when the correct analysis is performed, but there are also disadvantages when it requires time-sensitive data. The time-lapse from drawing the sample to analyzing it may take hours or even weeks. Taking so long could be a reason for machine damage even before knowing or interpreting the data. The best practice to minimize this risk is to ship the sample to the lab within 24 hours from when it is drawn.
Online Sampling: The next way of sampling is online sampling. This way, the sample is analyzed outside the location, which is not directly in line with the oil flow path. The oil keeps on flowing but at a lesser rate. The existing fitting could be utilized by making a loop to tap into the flow of the line directly, which helps to minimize the cost. This method helps obtain direct results and removes outer contamination sources’ impact. Although this system has some advantages, there are also disadvantages; one disadvantage is the misinterpretation of the sample size and equipment piping.
Inline Sampling: The third and last sampling technique is called inline sampling. This method sets a sensor in the direct path of flowing oil. The sensor that is in contact with the machine surface receives constant data regardless of the place it is positioned, whether after a pump or return line back to the machine’s reservoir. This approach may not seem to be feasible but provides the best result when implemented.
The online and inline engine oil sampling mentioned here comes under real-time engine oil analysis. For example, your car’s engine oil pressure gauge is a sensor that provides real-time results. These sensors show the instant condition of the machine, unlike offline engine oil sampling, where it needs individuals to manually pull a sample, ship it, and wait for its laboratory analysis and interpretation of the sample.
If you are someone related to the machine industry or a hot-rod vehicle owner who wants to avoid an engine failure, you have some good reasons to perform the engine oil analysis. We earlier mentioned that the oil in your engine is like the blood in your body, full of details; analyzing it will give you all the updates of its condition and also the condition of its carrier. Since you have rolled so far, you may have gained enough knowledge on engine oil capacity and its analysis program but make sure you are transforming the knowledge into practicality by surely performing an engine oil analysis for your vehicle or machine.