Process for Optimizing or Extending Oil Drain Intervals on Off Highway Trucks Equipped with a Centrifugal Oil Filter {1000, 1328, 1348} Caterpillar

Mining Truck

794 AC (S/N: HRT1-UP)

Off-Highway Truck/Tractor

793F (S/N: SND1-UP; SSP1-UP; SXP1-UP; D3T1-UP; RBT1-UP)

794 AC (S/N: MN51-UP; MT51-UP)

795F AC (S/N: ERM1-UP)

795FAC XQ (S/N: SNT1-UP)

797 (S/N: 5YW1-UP)

797B (S/N: JSM1-UP)

797F (S/N: LAJ1-UP; WSP1-UP; LTZ1-UP)

Introduction

A new lubrication system is available for C175 engines in Off-Highway trucks. This specially designed lubrication system allows longer oil drains. The lubrication system utilizes a centrifugal oil filter (COF) to remove soot and other harmful contaminants from the engine oil. In most applications, the engine oil life can be doubled. This lubrication system has demonstrated oil drains of 1000 hours and longer in test trucks equipped with the COF.

This Special Instruction describes the process required to validate the engine oil drain capability of the Off-Highway trucks at your job site. Job site operating conditions have a significant effect on the life of an engine oil. Variables like temperature, altitude, load factor, and haul road condition all play a part in determining the life of the oil. Also, there is variability in lubricant performance. High-performance lubricants will provide additional oil life and more component protection. Therefore, each job site must be evaluated to determine the optimal oil drain for the trucks.

Safety Section

Do not perform any procedure in this Special Instruction until you have read this special instruction and you understand this information. Use only proper tools and observe all precautions that pertain to the use of those tools. Failure to follow these procedures can result in personal injury. The following procedures should be observed.

Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs.

A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly.

Advantages of Optimized Oil Drains

Optimized oil drain programs have many advantages related to maintenance costs. In some continuous operations, the downtime required to perform the maintenance is the highest cost! Reducing downtime and reducing the cost of oil and oil filters will save money. Disposal costs must be considered. Depending on the location, disposal of used lubricants can be difficult and expensive. And finally there are advantages related to controlling contamination. Every time an engine is serviced there is a chance that dirt or dust could enter the crankcase. Reducing the number of oil and filter changes reduces the chance of accidental contamination.

Risk Factors

Oil drain optimization programs all involve some degree of risk! A missed or over-extended oil drain can severely damage an engine. It is vitally important that the maintenance practices at the job site are well managed. Engine oil samples must be taken within a narrow window of time. The service meter hours and the hours on the oil must be accurately recorded on each oil sample. Most importantly, personnel must be aware of the oil drain optimization process, and they must be monitoring the process to assure success.

Illustration 1	g06219832

The goal of this process is to optimize oil life without increasing wear rates or forming harmful deposits. The bearings in Illustration 1 have much of the overlay removed from corrosive wear. This type of wear can occur if the oil becomes corrosive. Oil sample results will show elevated levels of Oxidation and Lead (Pb) when this type of wear occurs.

Illustration 2	g06219938

Continued operation with severely worn bearings will result in scuffing and seizures. The bearings in Illustration 2 are severely worn and damaged from debris and seizure. Your optimized oil drain program should not damage components or accelerate wear rates. If serious problems arise, all related savings will be eliminated.

Illustration 3	g06219941

Illustration 4	g06219942

Abnormal piston deposits could also occur if oil drains are overextended. The piston in Illustration 3 shows a high level of deposits on the ring lands. These deposits can polish the cylinder liners, shown in Illustration 4. Polished cylinder liners and piston deposits will increase oil consumption. These problems will also increase blowby, and blowby will further deteriorate the engine oil. Deposits on piston undercrowns can also reduce the pistons cooling efficiency and result in premature piston failure.

Requirements of Optimized Oil Drains

The requirements for an optimized oil drain program may be divided into two groups. The first group consists of the components and consumables. The list below provides an outline of what is needed on the job site before the program is started.

• Premium diesel engine oil designed for extended life.

• C175 engine configuration with the Cat design Centrifugal Oil Filter (COF).

• Copper / Nickel engine oil cooler.

The second group contains the process requirements that must be in place and followed to manage the program. These requirements are based on the need for proper management of the program.

• Diligent program management.

• Cooperation and communication between the customer and the dealerships SIS Services department.

• Accurate maintenance records.

• Timely oil samples and oil drains.

Premium Diesel Engine Oils

For lowest risk, select one of the Caterpillar DEO-ULS oils for optimized oil drains. DEO-ULS is the highest performance diesel engine oil available from Caterpillar. There are three formulations available as shown in the chart below.

If DEO-ULS is not available, DEO 15-40 could be used. DEO 15W-40 meets Cat ECF-2 requirements and API CI-4.

If a Caterpillar oil is not used, then select a commercial diesel engine oil. There is no industry accepted oil specification for extended drain or extended life engine oils. However most oil companies offer premium products that are designed for extended oil drains. Consult with your oil supplier and select a commercial oil that is designed for severe service and extended oil drains. As a minimum the oil must meet API CK-4, or Cat ECF-2 and API CI-4.

Centrifugal Oil Filter

A specially designed centrifugal oil (COF) filter has been developed for the C175 engine. This COF has been designed to work with the C175 lube system. The lines, fittings, mounting hardware, and filter have been tested for durability and performance. Caterpillar cannot evaluate the performance or durability of aftermarket COFs.

Copper / Nickel Oil Cooler

When oil drains are extended, greater stress is placed on the lubricant. Sometimes, this stress on the lubricant will initiate oil cooler Cu leaching. Toward the end of the oil drain, Cu levels may increase and cause concern. To eliminate the chance of oil cooler Cu leaching, a Cu/Ni alloy oil cooler must be used in this program. Cu/Ni oil coolers have shown resistance to Cu leaching and have kept overall Cu levels lower.

Program Management & Communication

Extended oil drain programs must be approved by the customer. Even though the C175 with COF has been designed for longer oil drains, there is still risk involved. An over-extended oil drain or missing oil samples could damage the engine. Damage to the engine or shortened engine life must be avoided. Therefore, it is highly recommended that someone in the customers organization understands the risk, and provides the resources necessary to accomplish the various tasks. The customer must also work closely with Caterpillar dealer to ensure that all aspects of this program are followed. The SOS Services department at the dealership must also be aware an extended oil drain program is underway. SOS Services guidelines that were established for a standard oil drain, may not be applicable to the extended oil drain. Later in this document, there is a “Not-to-Exceed” list of recommended guidelines that covers key oil sample parameters

Maintenance & Repair Records

Accurate engine maintenance records are also needed to help understand the oil sample results. An engine that is nearing an overhaul will have different oil sample results than a reasonably new engine. Repairs or component replacements may introduce contaminants into the oil, and those contaminants will be detected in oil samples. These maintenance records should be provided to the dealerships SOS Services department for review and reference. Any new repairs or maintenance should be reported to the dealership, so that everyone involved is aware of engine condition.

Oil Samples

Oil samples should be taken in 100-hour increments, as the oil drain is extended beyond the baseline. For best results, these samples should be taken in a timely manner. These 100-hour samples should be taken within 10 or 15 hours of the target time. The oil samples should be analyzed by a Caterpillar dealer with the capability to run all the standard tests in the SOS Services program. There are tests in place to measure wear, oil deterioration, and oil contamination from various sources. A list of the standard SOS Service tests is shown in Table 2.

Within this list of oil tests, there are five results that should be watched closely: (Fe), (Pb), Soot, Oxidation, and Viscosity. Soot and Oxidation increase with time in a diesel engine oil.

Soot primarily causes iron to increase due to wear of the cylinder pack components. Oxidation will lead to corrosive wear. A significant increase in (Pb) signals that corrosive wear is occurring. Viscosity will increase with elevated Soot and elevated Oxidation. Therefore, Viscosity is a good overall measure of oil health. As these parameters increase, the oil becomes degraded. Modern high-performance oils are designed to control the wear caused by soot and oxidation. Careful monitoring and plotting of these results will allow you to get the full use out of your oil and the longest oil drains, without harming the engine.

Do not ignore the other oil sample results when extending oil drains. Dirt, coolant, or fuel, contamination could occur at any time. Dirt is identified by increases in Si and Al. Coolant contamination is found by measuring the typical coolant additives: Na and K. Fuel dilution or fuel contamination shows up as a decrease in viscosity and a 6% or higher GC result. These contaminants can build up and cause increased wear. If this happens, repairs must be made to stop the contamination. Unfortunately, the only way to remove these contaminants is to change the oil.

Optimized Oil Drain Process

If you have all the requirements in place, it is time to start the process of extending the oil drain. The first step is to establish a baseline for your test truck or test trucks. If you have a large fleet, it is best to test the long drains in 2 or 3 trucks. Select trucks with newer or in mid-life engines. Engines near overhaul may not be in the best condition for this evaluation. Baseline analysis requires an evaluation of the oil sample results at your current oil drain. If you are starting with new trucks, then use the oil drain recommended in the OMM for the baseline. Complete at least two oil drains on the new trucks to establish the baseline.

Using the baseline test results, plot the historic results for: (Fe), (Pb), Soot, Oxidation, and Viscosity. Plot these results versus oil hours, and create a regression line. Extend the regression line approximately 1.5 times longer than your current oil drain. This extended regression line establishes your target oil drain. For example, if the baseline oil drain is 500 hours, the target oil drain is 750 hours.

Note: Caterpillar has successfully demonstrated oil drain intervals up to 1500 hrs and does not recommend extending beyond this point.

Table 3 establishes a set of Not-to-Exceed recommendations for oil sample results. These values are valid at any oil hours. Check the results for the projected regression line, and make sure that they do not exceed any of these values. If these values are exceeded, the engine may need repair. Or, the operation of this engine is not acceptable for extended oil drains.

The plots below (Illustration 5) show the baseline results from a truck that was equipped with the Cat COF and the Cu/Ni oil cooler. Three oil drains were completed at approximately 500-hours. The key test results were plotted and regression lines were created. The dotted line on the plots represents the Not-to-Exceed recommendations. The regression line was extended to about 1.5 times the baseline oil drain. As the plots show, none of the extended regression lines exceed the recommended values in Table 3.

Illustration 5	g06219992

The next step is to select the target oil drain for the extension. The target oil drain should be approximately 1.5 times the baseline oil drain. Since the baseline oil drains were in the 500 to 600-hour range, the target oil drain was set at 800-hours.

Illustration 6	g06221980

This next set of plots in Illustration 6 show the results from four extended oil drains. The last oil drain was at 868 hours. The key oil sample results were still linear out to almost 900 oil hours. Also, these key results did not reach the Not-to-Exceed recommended values. This truck thereby demonstrated acceptable 1000-hour oil drains. At this point, oil sampling can also be reduced to 250-hour intervals. This 1000-hour oil drain could be applied to other 797F trucks in the fleet.

Note: A similar extension process should be followed for C175-16 engines in the fleet.

Illustration 7	g06221983

A Note of Caution

Do not skip this verification program and go directly to the target oil drain. This verification program is set up with more frequent oil sampling to provide safe operation. This next example shows how quickly an oil deterioration problem can occur. The engine in this example is a 3516B HD. The engine was run on a dyno at a high load factor. The key oil sample results looked good, out to 250 oil hours, see Illustration 7. The regression lines were linear and the values were low.

Illustration 8	g06221985

The oil was not changed, and the test engine was run for an additional 138 hours, shown in Illustration 8. At 300 hours on the oil, there was a small increase in (Pb). The other key results stayed on a linear trend. The small increase in (Pb) was not in itself significant. However, the next sample at 350 oil hours showed a much larger increase in (Pb). Therefore, the (Pb) increase at 300 hours was an early signal that the oil was degrading. Also by 350 oil hours, the Iron (Fe) and Oxidation had increased significantly. This action verified that the oil had significantly degraded and become corrosive. The test was ended at 388 oil hours.

Illustration 9	g06221988

The test was concluded before a catastrophic engine failure occurred. However, there was damage done by the degraded oil. The main bearings in Illustration 9 were removed from the test engine. Severe overlay corrosion removed much of the overlay from these bearings. Bearing overlay corrosion is not the only failure mode which can be caused by continuing to run with degraded oil.

Severely degraded oil can cause:

1. Excessive piston deposits.

2. Sludge and lacquer in the crankcase.

3. Oil filter plugging.

Centrifugal Oil Filter (COF) Service Extension

Illustration 10	g06360920

The service interval for the COF can be extended beyond the initial mainitenance interval recommended in the Operation and Maintenance Manual. It is recommended to extend the service life of the COF in 500 hour increments. At each interval the thickness of the sludge build up on the COF paper should be measured and the COF rotor should then be properly cleaned. The maximum thickness of the sludge is 42 mm (1.6 inch). If the measured sludge exceeds 42 mm (1.6 inch) the COF service interval must be shortened.

Illustration 11	g06221989

COF FAQ's

1. A new oil supplier is telling us their oil has the ability to extend drain intervals (synthetic). Can we extend because of this new oil blend?

   No. Oil analysis must be utilized to evaluate health of the oil against current limits and that engine wear rates have not changed.

2. Can we install a third-party COF and extend drain intervals same as with the CAT Centrifugal Filter System.

   NO. The CAT system has been designed specifically for the C175 engine to ensure it does not negatively affect oil flows and pressures to core components and to provide adequate cleaning of the oil to allow extended drain intervals.

3. Do I need to clean my COF and change the paper every service interval?

   NO. The clean out of the COF and replacement of the paper sleeve could be managed by COF buildup thickness. The maximum sludge thickness is 42 mm (1.6 inch).

4. If I bolt on a COF kit, can I immediately double the oil drain interval?

   NO. Oil analysis must be used to access capability to extend the oil drain intervals.

5. Is the new soot value a limit or guideline?

   GUIDELINE. The new soot guideline of 90 UFM is what CAT has validated the product against as part of the extended oil drain interval program. Extending beyond this new guideline requires the customer continue to use SOS trend analysis to monitor oil health and engine wear rates are not accelerated.

6. Do I need to upgrade my oil cooler with installation of the COF system?

   YES. The risk of not upgrading to the CuNi cooler is elevated levels of Cu in the oil which can lead to excessive buildup of carbon on bottoms of pistons and turbo shafts which could lead to premature component failure.

7. If customers use a third-party oil lab. Is this a problem?

   No, it is not an issue. The same process for extending oil drains should be followed. Reference Table above. The dealer should communicate these "Not to Exceed Recommendations" to the oil analysis lab and which serial numbers have the COF kit installed and are extending oil drains so this information can be included in the engine oil analysis.

8. If one of my trucks was part of the field follow program, can I immediately take additional COF-equipped trucks to the extended oil drain interval achieved by my field follow truck?

   No. Make sure that you are able to replicate what was done during field follow with the production COF kit. Changes to oil formulation, haul cycle, load factor are all factors that may impact extended oil drain intervals.

9. How often do I need to change my cartridge oil filters?

   Every time the engine oil is drained or when diagnostics indicate that there is high delta pressure across the filters.

10. How long can I run the cartridge oil filters in an engine equipped with a COF kit?

    Caterpillar has successfully demonstrated cartridge oil filter capacity of 1000 hours and continues to evaluate additional filter life.