Section 5.2
Lubricating Oil
Hundreds of commercial oils are marketed today, but labeling terminology differs among suppliers and can be confusing. Some manufacturers may claim that their lubricant is suitable for all makes of diesel engines and may list engine makes and types, including Detroit Diesel, on their containers. Such claims by themselves are insufficient as a method of lubricant selection for Detroit Diesel engines.
The proper lubricating oil for all Detroit Diesel engines is selected based on SAE Viscosity Grade and API (American Petroleum Institute) Service Designation. Both of these properties are displayed in the API symbol shown within the specific requirements.
Detroit Diesel recommends using only lubricants meeting the criteria listed in Table "Recommended Engine Oil" .
Specification |
Recommendation |
SAE Viscosity Grade |
15W-40 |
API Classification |
CG-4 |
Military Specification |
MIL-L-2104E |
HT/HS Viscosity |
3.7 cP (minimum) |
Lubricants meeting these criteria have provided maximum engine life, when used in conjunction with recommended oil drain and filter maintenance schedules. See Figure "API Symbol" for the proper API symbol.

Figure 1. API Symbol
The API CG-4 performance category was introduced in January 1995. Lubricants meeting CG-4 criteria are intended for use primarily with low (0.05%) sulfur fuel. Compared to API CF-4 certified oils, these oils have improved soot and deposit control, in addition to enhanced wear control. API CF-4 oils may be used when CG-4 is not available.
NOTICE: |
Monograde oils should not be used regardless of API Service Classification. Failure to observe this precaution may result in inadequate lubrication and severe engine damage. |
When the use of high sulfur fuel (greater than 0.5% mass sulfur) is unavoidable, higher alkalinity lubricants are recommended. High sulfur fuels require modification to oil drain intervals.
Section 5.2.1
SAE Viscosity Grade
Viscosity is a measure of an oil's ability to flow at various temperatures. The SAE viscosity grade system is defined in SAE Standard J300, which designates a viscosity range with a grade number. Lubricants with two grade numbers separated by a W, such as 15W-40, are classified as multigrade. Those with a single number are monograde. The higher the number, the higher the viscosity.
The kinematic viscosity ranges with the associated SAE viscosity grade are listed in Table "SAE Viscosity Grades for Engine Oils" . This table is taken from SAE Standard J300.
Note: Grades designated with a W are required to meet low temperature viscosity requirements and high temperature/high shear viscosity requirements.
SAE Viscosity Grade |
Viscosity (cP) at Temperature ( °C), MaximumCrankingASTM D 5293 |
Viscosity (cP) at Temperature ( °C), MaximumCrankingASTM D 4684 |
Viscosity(cSt) at 100°C Minimum |
Viscosity(cSt) at 100°C Maximum |
HighTemperatureHigh Shear Rate Viscosity @ 150°C & 10 5 second |
0W |
3250 at -30 |
30,000 at -35 |
3.8 |
- |
- |
5W |
3500 at -25 |
30,000 at -30 |
3.8 |
- |
- |
10W |
3500 at -20 |
30,000 at -25 |
4.1 |
- |
- |
15W |
3500 at -15 |
30,000 at -20 |
5.6 |
- |
- |
20W |
4500 at -10 |
30,000 at -15 |
5.6 |
- |
- |
25W |
6000 at -5 |
30,000 at -10 |
9.3 |
- |
- |
20 |
- |
- |
5.6 |
9.3 |
>2.6 |
30 |
- |
- |
9.3 |
12.5 |
>2.9 |
40 |
- |
- |
12.5 |
16.3 |
>3.7 |
50 |
- |
- |
16.3 |
21.9 |
>3.7 |
60 |
- |
- |
21.9 |
26.1 |
>3.7 |
Section 5.2.2
Additional Requirements
Although the API designation identifies the minimum desirable performance levels, Detroit Diesel has identified additional properties that further assure the best possible engine lubrication.
Refer to "5.2.3 High Temperature/High Shear Viscosity" for high temperature and high shear viscosity requirement.
Refer to "5.2.4 API Service Classification" for API Service classification clarification.
Refer to "5.2.5 API Symbol" for API Symbol clarification.
Refer to "5.2.6 Sulfated Ash and Total Base Number" for sulfated ash and total base number limits.
Refer to "5.2.7 Universal Oils" for clarification on universal oil selection.
Refer to "5.2.8 Synthetic Oils" for synthetic oil requirements.
Refer to "5.2.9 The Use of Supplemental Additives" for the use of supplemental additives.
Refer to "5.2.10 Waste Oil Disposal and Re-refined Oils" for oil disposal and re-refined oils.
Section 5.2.3
High Temperature/High Shear Viscosity
Unlike kinematic viscosity, High Temperature/High Shear (HT/HS) viscosity is measured under conditions similar to those of an operating engine. The test is conducted at 150°C under shear stress conditions, similar to those found in thin film lubrication areas, like the piston ring-to-cylinder wall interface. The value obtained indicates the temporary shear stability of the viscosity index improver used in multigrade oils. In 15W-40 grade oils, an HT/HS viscosity below 3.7 centipoise (cP) indicates that the oil will not perform as a 40 grade oil under engine operating conditions.
HT/HS viscosity has recently been incorporated into the J300 standard. Oils conforming to this specification meet the minimum HT/HS values required by Detroit Diesel engines.
Section 5.2.4
API Service Classification
The American Petroleum Institute (API) has developed a means of classifying lubricants for different engines and applications. The highest performance classifications include API CF, CF-2, CF-4, and CG-4. Detroit Diesel does not recommend the use of older and lower performance classifications, including API CE, CD, CC, and CB. Qualifying tests for these classifications have been discontinued.
When multiple API classifications are used, ensure that the classification specified by Detroit Diesel is listed. Oils designated SG or SH are for passenger car applications. Detroit Diesel recommends oils without these designations.
Section 5.2.5
API Symbol
Lubricant marketers have adopted a uniform method of displaying the SAE viscosity and API service classification on product containers and in product literature. The three segment donut contains the SAE grade number in the center and the API service classification in the top segment. The lower segment is used to designate the energy conservation status for gasoline engines and has no significance for diesel engines.
A marketer is required to license his oil with API in order to display the symbol. Some marketers may indicate that their products meet API requirements. This is not adequate. Although the licensing process cannot guarantee good oil performance, the marketer must be able to produce data to substantiate that their oil meets the service classification.
Note: Only oils licensed by API should be used in Detroit Diesel engines.
Section 5.2.6
Sulfated Ash and Total Base Number
Sulfated ash is a lubricant property measured by a laboratory test (ASTM D 874) to determine the potential for formation of metallic ash. The ash residue is related to the oil's additive composition and is significant in predicting lubricants, which may cause valve distress under certain operating conditions. Sulfated ash is related to the Total Base Number (TBN), which measures an oil's alkalinity and ability to neutralize acid using a laboratory test (ASTM D 2896 or D 4739). As TBN increases, sulfated ash also increases to where lubricants with TBNs above 10 will likely have sulfated ash contents above 1.0% mass.
Total Base Number is important to deposit control in four-stroke cycle diesel engines and to neutralize the effects of high sulfur fuel in all diesel engines.
When the use of oil with high ash content is required, such as with high sulfur fuel, the oil selected should have the highest TBN (D 2896) to Ash (D 874) ratio possible. For example, an oil with a TBN of 10 and an Ash of 1.2% mass is less desirable than an oil with same TBN and 1.0% Ash. Also refer to "5.2.12 Oil Change Intervals" for Change Intervals.
Section 5.2.7
Universal Oils
Universal oils are designed for use with both gasoline and diesel engines and provide an operational convenience in mixed engine fleets. These products are identified with combination API category designations, such as SG/CF or CF-4/SH. Although such products can be used in Detroit Diesel engines (provided they satisfy all Detroit Diesel requirements), they are not as desirable as lubricants formulated specifically for diesel engines and having API CF-2 or CF-4/CG-4 designations. When selecting a universal oil, select one with the C category first, since this is primarily intended for diesel service.
Section 5.2.8
Synthetic Oils
Synthetic oils may be used in Detroit Diesel engines, provided they are API licensed and meet the performance and chemical requirements for non-synthetic oils.
Product information about synthetic oils should be reviewed carefully. Synthetic oils offer improved low temperature flow properties and high temperature oxidation resistance. However, they are generally more costly than non-synthetic oils. Performance additive systems often respond differently in synthetic oils.
Section 5.2.9
The Use of Supplemental Additives
The use of supplemental additives break-in oils, top oils, graphitizers, and friction-reducing compounds is not necessary and can upset the oil's formulation, causing performance to deteriorate. Engine damage resulting from the use of such materials is not covered by warranty.
Section 5.2.10
Waste Oil Disposal and Re-refined Oils
Dispose of used lubricating oil and filters in an environmentally responsible manner, according to federal (EPA) and state recommendations. The disposal of waste oil may be best addressed by the engine oil supplier, who may accept responsibility for proper disposal of this material as part of the business of providing lubricant.
Detroit Diesel permits the use of re-refined oils in all engine product lines, provided the re-refined oil meets the appropriate SAE viscosity and API specifications.
Section 5.2.11
Brand Name Approved Lubricants
Detroit Diesel does not maintain a list of brand name approved products. All lubricants meeting the standards set for Detroit Diesel engines will provide satisfactory performance when used in conjunction with the oil drain and filter requirements. To ensure that a lubricant under consideration meets these qualifications, the customer should ensure that the oil has a current API license number. The lubricant supplier should be able to supply this information, but it may also be obtained from other sources. Refer to Detroit Diesel publication 7SE270, Lubricating Oil, Fuel, and Filters , for further information.
The typical chemical and physical properties of a lubricant meeting Detroit Diesel requirements in normal applications are listed in Table "Typical Properties" . This table does not provide specifications, nor should it be used by itself to select an engine lubricant.
Viscosity Grade (API Service) |
15W-40 (CF-4/CG-4) |
Kinematic Viscosity at 40° C, cST |
95-115 |
Kinematic Viscosity at 100 ° C, cST |
12.5-16.3 |
HT/HS cP 150° C |
3.7 min |
Viscosity Index |
130 |
Pour Point °C, max. |
-23 |
Flash Point °C, min. |
215 |
Sulfated Ash, % mass |
20 max. |
Total Base Number |
Above 6.0 |
Zinc |
Above 700 ppm |
Section 5.2.12
Oil Change Intervals
Engine lubricating oil deteriorates over time from contact with combustion by-products and engine contaminants. Certain additives become depleted with use. Therefore, regular oil drain intervals are necessary. These intervals vary in length, depending on engine operation and fuel and lubricant quality. As a rule, shorter oil drain intervals extend engine life; longer oil drain intervals, however, can reduce engine longevity.
The oil drain intervals listed in Table "Maximum Allowable Oil Drain Intervals-- Normal Operation with Low Sulfur Fuel" (normal operation with low sulfur fuel), and the oil change intervals listed in Table "Maximum Allowable Oil Drain Intervals--Fuel Sulfur Above 0.5% (Use oil analysis to determine optimum drain interval)" should be considered maximum and should not be exceeded.
Service Application |
Oil Drain Interval |
On-highway Truck |
15,000 Miles (24,000 km)* |
*Recommended oil drain interval is 12,000 miles (19,300 km).
Service Application |
Oil Drain Interval New Oil TBN above 10 |
On-highway Truck |
10,000 Miles (16,000 km) |
Note: Always install a new oil filter when the oil is changed.
Section 5.2.13
Using High Sulfur Fuels
Although only diesel fuels containing more than 0.5% sulfur are considered high sulfur fuels, piston ring wear studies indicate that fuels containing more than 0.3% sulfur significantly increase ring face wear rates. See Figure "Effect of Fuel Sulfur Content on Engine Life" .

Figure 2. Effect of Fuel Sulfur Content on Engine Life
High sulfur content forms acid during combustion, particularly during idling and low temperature operation. To minimize the effects of high sulfur content, shorten oil drain intervals. The appropriate oil drain interval may be determined by oil analysis or the oil change intervals listed in Table "Maximum Allowable Oil Drain Intervals--Fuel Sulfur Above 0.5% (Use oil analysis to determine optimum drain interval)" .
Section 5.2.14
Used Lubricating Oil Analysis
Detroit Diesel recommends a used oil analysis program, such as Power Trac, to monitor engine crankcase oil. Oil analysis involves a series of laboratory tests performed on the engine lubricant. Most tests indicate engine conditions, while others indicate lubricant condition. Since oil analysis cannot comprehensively assess the lubricating oil, it should not be used to extend oil drain intervals. An oil analysis program with regular sampling should be implemented, and the oil should be changed whenever contamination exceeds the warning limits listed in Table "Single Sample Used Oil Analysis Warnings Limits" .
Description |
ASTMDesignation |
Condition Measured |
Requirement |
Viscosity at 40°C (74°F), cSt % Maximum Increase |
D445 |
Engine and Oil |
40.0 |
Viscosity at 40°C (74°F), cSt % Maximum Decrease |
D445 |
Engine and Oil |
40.0 |
Carbon, (Soot) Content, TGA Mass % Maximum |
E 1131 |
Engine Combustion |
1.5 |
Pentane Insolubles, % Maximum |
D 893 |
Engine Combustion |
2.0 |
Total Base Number (TBN) Minimum |
D 4739 |
Oil |
1.0 |
Total Base Number (TBN) Minimum |
D 2896 |
Oil |
2.0 |
Water, Volume % Maximum |
D 1744 |
Engine |
0.30 |
Fuel Volume % Maximum |
D 3524 |
Engine |
2.5 |
Glycol Volume. ppm Maximum |
D 2982 |
Engine |
700 |
Iron, Fe ppm Maximum |
D 5185 |
Engine Wear |
200 |
Copper, Cu ppm, Maximum (Above Baseline) |
D 5185 |
Engine Wear |
10 |
Section 5.2.15
Oil Filter
The oil filter requirements are listed in Table "Lubricating Oil Filter Requirements" .
Filter Type |
Micron Rating @ 98% Single Pass Efficiency |
Full-Flow |
25-28 |
Full-Flow |
25-28 |
Never conclude, on the basis of a single measurement exceeding warning limits, that the engine is worn out. Imminent engine wear out can only be determined by continuous oil analysis. A decision to overhaul the engine should be based on operational data (for example, increasing oil consumption and crankcase pressure) and physical parts inspection.
Series 40E Service Manual - 6SE410 |
Generated on 10-13-2008 |