Diesel Motor Oil Guide | Cummins, Power Stroke, Duramax

Oil Viscosity & Grade

Engine oil viscosity grades identify the lubricants basic chemical and mechanical properties. The numbers themselves are not indicative of a single specific property, only that the characteristics fall within the acceptable range of properties for that oil grade (including kinematic and dynamic viscosities) as specified by SAE guidelines. The "W" acronym found on oil grades corresponds to the oil's "winter" viscosity grade. The second number, following the dash, specifies the oil's hot temperature grade. To maximize engine protection, it is necessary for most engines to require an oil that displays different properties depending on the ambient and/or operating temperature. Manufacturers often specify oil grade requirements based on ambient temperature and these recommendations should be closely followed.

The lower the viscosity grade, the thinner and less viscous the oil is. A low viscosity oil consequently flows easier than a more viscous oil. Multi-grade oils use viscosity modifiers to obtain their specific properties. In addition to an oil's viscosity grade, modern engine oils also include API (American Petroleum Institute) ratings, which require manufacturers to adhere to specific performance characteristics. The API test requirements include chemical limitations, engine seal compatibility, foaming characteristics, corrosion properties at high temperature, and shear stability. An API certified low ash engine oil, for example, is required in all modern diesel particulate filter equipped trucks. Selecting an engine oil that meets the API category specified by the engine manufacturer is critical in modern engines equipped with emissions controls, particularly those with exhaust aftertreatment systems. In such applications, failure to select an engine oil that meets the specified API category may result in DPF clogging and related issues. Note that API standards are frequently superseded as older standards become defunct.

API Engine Oil Categories

API categories are almost always backwards compatible (with few exceptions) and almost never forwards compatible. Selecting an appropriate API category oil is critical on modern vehicles with exhaust aftertreatment systems.

API Category	Description	Remarks
FA-4	Low ash engine oil with specific properties that combat shear, oxidation, and viscosity loss at high temperatures and stresses. Provides protections for exhaust aftertreatment systems.	Not interchangeable or cross compatible with "C" category engine oils. Not compatible with LSD; diesel fuel with a maximum sulfur content of 15 ppm (ULSD) required.
CK-4	Low ash engine oil providing protections for exhaust aftertreatment systems.	Exceeds performance criteria for API CJ-4, CI-4, and CH-4 categories; can be be used in applications requiring any of these categories.
CJ-4	Low ash engine oil designed for 2010 model year emissions standards.	Exceeds performance criteria for API CI-4, CH-4, CG-4, and CF-4 categories; can be used in applications requiring any of these categories.
CI-4	Engine oil designed to meet 2004 model year emissions standards. Specifically formulated for engines equipped with EGR systems.	Exceeds performance criteria for API CH-4, CG-4, CF-4, CE, and CD categories; can be used in applications requiring any of these categories. Not for use in modern engines with exhaust aftertreatment systems.
CH-4	Engine oil designed to meet 1998 model year emissions standards.	Exceeds performance criteria for API CF-4, CG-4, CD, and CE categories; can be used in applications requiring any of these categories. Not for use in modern engines with exhaust aftertreatment systems.
CG-4, CF-4, CF-2, CF	Obsolete standard, performance criteria superseded by current categories.	Superseded by one or more categories listed above. Use API CH-4, CI-4, CJ-4, or CK-4 category engine oil in place of all obsolete standards. Not compatible with modern emissions systems, including vehicles equipped with exhaust gas recirculation and diesel particulate filter systems.
CE, CD-II, CD	Obsolete standard, performance criteria superseded by current categories.

Oil Change Intervals - Normal vs Severe Duty

Automakers historically provide a "normal" service interval in addition to a "severe" or "heavy duty" interval. In instances that the intervals are not subdivided, the service procedure is unlikely affected by operating conditions or the engine relies on an oil life or oil change monitoring system that alerts the driver when service is needed. Always service an engine as prompted by the oil life/oil life/service procedure monitoring system unless the recommended interval is reached before any indicators are triggered. "Severe" or "heavy duty" maintenance intervals should be followed when operating under certain conditions, which include 1) periods of excessive idling, 2) frequent short trips that do not allow the engine to reach operating temperature, 3) driving on dusty roads, 4) driving off-road or engaging 4 wheel drive, 5) using biodiesel, and most importantly 6) frequent towing/hauling. When in doubt, adhere to the "severe" duty requirements provided by the manufacturer. Refer to your owners manual for additional driving conditions that may alter your vehicle's maintenance schedule. Never exceed the manufacturer's recommended maintenance intervals for any reason.

Oil Specifications by Manufacturer

The following chart highlights the use of and meanings behind various superscript acronyms used in the oil charts below.

Oil Chart Acronyms
^N	Service interval for normal driving conditions (no towing/hauling, excessive idling, etc)
^S	Service interval for severe driving conditions, which includes towing, hauling, extended periods of idling, operating in extreme hot/cold temperatures, and off-road use
^P	Viscosity is preferred within the listed temperature range to alternative viscosity grades with similar or overlapping temperature ranges
^B	Viscosity is required when using biodiesel fuels and used within the listed temperature range.

Ford/Power Stroke/International Diesel

Application(s)	Oil Capacity	Service Interval(s)	Oil Filter P/N	Oil Viscosities
6.9L IDI (1983 - 1987)	10 qts w/ filter ^[1]	5,000 mi/6 mo ^N 2,500 mi/3 mo ^S	FL784	SAE 30 (temp > 30° F) ^P SAE 15W-40 (temp > 0° F) SAE 10W-30 (temp < 60° F) ^P
7.3L IDI (1988 - 1994)	10 qts w/ filter ^[1]	5,000 mi/6 mo ^N 2,500 mi/3 mo ^S	FL784	SAE 30 (temp > 30° F) ^P SAE 15W-40 (temp > 0° F) SAE 10W-30 (temp < 60° F) ^P
7.3L Power Stroke (1994 - 2003)	15 qts w/ filter	5,000 mi/6 mo ^N 3,000 mi/3 mo ^S	FL1995	SAE 15W-40 API CG-4/SH (temp > 10° F) ^P SAE 10W-30 API CG-4/SH (temp -10 to 90° F) SAE 5W-30 API CG-4/SH (temp < 30° F) SAE 0W-30 API CG-4/SH (temp < 0° F)
6.0L Power Stroke (2003 - 2007)	15 qts w/ filter	7,500 mi/6 mo ^N 5,000 mi/6 mo ^S	FL2016	SAE 15W-40 API CI-4/CH-4 (temp > 10° F) ^P SAE 10W-30 API CI-4/CH-4 (temp -10 to 90° F) SAE 5W-30 API CI-4/CH-4 (temp < 30° F) SAE 0W-30 API CI-4/CH-4 (temp < 0° F)
6.4L Power Stroke (2008 - 2010)	15 qts w/ filter	7,500 mi/6 mo ^N 5,000 mi/6 mo ^S	FL2016	SAE 15W-40 API CJ-4 (temp > 10° F) ^P SAE 10W-30 API CJ-4 (temp -10 to 90° F) SAE 5W-30 API CJ-4 (temp < 30° F) SAE 0W-30 API CJ-4 (temp < 0° F)
3.2L Power Stroke (2015 - 2019 Transit)	12 qts w/ filter	10,000 mi ^N 5,000 mi/6 mo ^S	FL500S	5W-30/5W-40 API CJ-4 (temp > -20° F)^P SAE 0W-30/0W-40 API CJ-4 (all temps) SAE 15W-40 API CJ-4 full synthetic ^B
3.0L Power Stroke (2018 - current F-150)	6.5 qts w/ filter	10,000 mi max ^[2]	FL2081	SAE 5W-30 API FA-4 (temp > -20° F) SAE 10W-30 API FA-4 (temp > 0° F) SAE 5W-40 API CK-4 (temp > -20° F) ^P,B SAE 0W-40 CK-4 (temp < -20° F)
6.7L Power Stroke (2011 - current)	13 qts w/ filter (2011 - 2016) 15 qts w/ filter (2017)	10,000 mi max ^[2]	FL2051S	SAE 10W-30 (temp > 0° F) SAE 5W-40 (temp temp > -20° F) ^P,B SAE 15W-40 (temp temp > 20° F) ^B SAE 0W-30/0W-40 (all temps) All engine oils must meet API CJ-4 and Ford WSS-M2C171-F1 specifications.

^[1] Ford F-Series and E-Series engine oil capacity; 6.9L/7.3L IDI engines found in International truck or other medium to heavy duty applications may have a higher engine oil capacity.
^[2] Vehicle equipped with an intelligent oil life monitor system; change engine oil and filter when prompted through driver information display. Do not exceed listed interval between oil changes. Intelligent oil life system will not compensate for biodiesel usage, which will require more frequent service.

Dodge/Ram/Cummins Diesel

Application(s)	Oil Capacity	Oil Change Interval(s)	Oil Filter P/N	Oil Viscosities & Required Specifications
5.9L Cummins 6BT (1989 - 1998)	12 qts w/ filter	6,000 mi/6 mo ^N 3,000 mi/3 mo ^S	Fleetguard LF16035	SAE 15W-40 (ambient temp > 10° F) SAE 10W-30 (ambient temp 0 to 30° F w/o block heater, < 0° F w/ block heater) SAE 5W-30 (ambient temp < 0° F w/o block heater)
5.9L Cummins ISB (1998 - 2002)	12 qts w/ filter	7,500 mi/6 mo ^N 3,750 mi ^S	Fleetguard LF16035	SAE 15W-40 (ambient temp > 0° F) ^P SAE 5W-40 full synthetic (all temps)
5.9L Cummins ISB (2003 - 2007)	12 qts w/ filter	15,000 mi/12 mo ^N 7,500 mi/6 mo ^S	Fleetguard LF16035
6.7L Cummins ISB (2007.5 - 2012)	12 qts w/ filter	7,500 mi/6 mo ^[1]	Fleetguard LF16035	SAE 15W-40 API CJ-4 (temp > 0° F) SAE 5W-40 API CK-4 full synthetic (temp < 0° F)
6.7L Cummins ISB (2013 - 2018)		15,000 mi/6 mo ^[1] 12,500 mi/6 mo ^B
6.7L Cummins ISB (2019+)		15,000 mi/6 mo ^[1] 12,500 mi/6 mo ^B		SAE 10W-30 API CK-4 (temp > 0° F) SAE 5W-40 API CK-4 full synthetic (temp < 0° F)
3.0L EcoDiesel (2014 - 2019)	10.5 qts w/ filter	10,000 mi/12 mo ^N,[1] 8,000 mi/6 mo ^B	MOPAR 6822 9402AA	SAE 5W-40 API CJ-4 full synthetic
3.0L EcoDiesel (2020+)	8.5 qts w/ filter	10,000 mi/12 mo ^N,[1] 8,000 mi/6 mo ^B	MOPAR 6822 9402AA	SAE 5W-40 full synthetic, API SN/FCA material spec MS-12991
5.0L Cummins ISV5.0 (2015 - 2017)	10 qts w/ filter	10,000 mi/12 mo ^N 8,000 mi/6 mo ^B 5,000 mi ^S	Fleetguard LF17517	SAE 10W-30 API CJ-4 (temp > -10 ° F) SAE 5W-40 API CJ-4 (temp < 68 ° F)

^[1] Vehicle is equipped with an oil life monitor system and will indicate to driver through instrument cluster display when an oil change is due. Oil should be changed as prompted by the oil life monitor and should not exceed the listed limit.

GM/Duramax/Detroit Diesel

Application(s)	Oil Capacity		Oil Change Interval(s)	Oil Filter P/N	Oil Viscosities
6.2L GM (1982 - 1993)	7 qts w/ filter		5,000 mi ^N 2,500 mi ^S	ACDelco PF1218	SAE 15W-40 (temp > 0° F) ^P SAE 30W (temp > 32° F) SAE 10W-30 (temp < 32° F)
6.5L GM/Detroit V-8 (1992 - 2002)	1992 - 1998	7 qts w/ filter	5,000 mi ^N 2,500 mi ^S		SAE 15W-40 temp > 0° F) ^P SAE 30W (temp > 32° F) SAE 10W-30 (temp < 32° F)
	1999+	8 qts w/ filter
6.6L Duramax (2001 - 2007)	10 qts w/ filter		10,000 mi/12 mo ^[1]	ACDelco PF2232	SAE 15W-40 API CI-4/CH-4 (temp > 0° F) SAE 5W-40 API CI-4/CH-4 (temp < 0° F)
6.6L Duramax (2007.5+)					SAE 15W-40 API CJ-4 (temp > 0° F) SAE 5W-40 API CJ-4 (temp < 0° F)
2.8L Duramax (2016+)	6.0 qts w/ filter		As prompted ^[1]	ACDelco PF2262G	SAE 5W-30 meeting Dexos2 spec (ambient temp > -20 ° F) ^P SAE 0W-40 meeting Dexos2 (ambient temp < -20 ° F)
3.0L Duramax (2020+)	7.0 qts w/ filter		As prompted ^[1]	ACDelco PF66	SAE 0W-20 meeting GM dexosD spec

Diesel Oil Recommendations

Synthetic vs Conventional Oil

Synthetic engine oil is superior in every way, shape, and form, although they tend to cost slightly more than a conventional petroleum based motor oil. The benefits of synthetic motor oils include:

Resilience to chemical breakdown - Motor oil contamination and the corresponding chemical breakdown of engine oil is a major, if not the most profound concern in diesel engines. There are two significant sources of contamination; fuel dilution and soot infiltration. Diesel fuel and soot in exhaust gases find there way into the crankcase naturally through blowby. To a degree, fuel dilution is completely normal and unavoidable. However, modern diesel engines tend to suffer more predominantly from fuel dilution, especially those that use a post-injection event as a means of heating the exhaust stream during regeneration cycles. Excessive idling and cold weather operation also contribute to greater degrees of fuel dilution as a result of cylinder washing due to relatively cool combustion temperatures. Fuel dilution lowers the viscosity of engine oil, making it thinner. Soot contamination increases viscosity, making the oil thicker, and tends to be fairly abrasive. Both have undesirable effects on the properties of engine oil, thus a synthetic oil with a high resilience to these contaminants is desirable.

Resilience to thermal breakdown - Most diesel engines have a normal operating temperature of 185 - 205 ° F. This means that your engine oil is also experiencing temperatures in this range. But it's not normal engine temperature that is a huge concern with regard to thermal breakdown, especially considering that most diesels utilize an oil cooler. The turbocharger, however, produces a tremendous amount of heat that is removed by pumping engine oil through the bearing channels. A synthetic motor oil is far more resilient to high temperatures and breaks down at a significantly slower rate, thus better maintaining its lubricant properties between oil change intervals.

Resilience to mechanical breakdown (shear) - Engine oil experiences intense shear forces in any engine, regardless of fuel type. Engine oil must create a barrier between two or more metal surfaces in motion, absorbing the forces that are transmitted between gears, bearings, rods, and pins. The extreme force and pressure that is created between these surfaces contributes to oil breakdown. This form of breakdown is typically referred to as shear, and once again synthetic oils are much more resilient than conventional petroleum based oils.

It's never too late to switch to synthetic motor oil and it is completely compatible with conventional petroleum oils. There is therefore no special process required when converting to synthetic oils; simply drain and refill. Synthetic engine oils, despite a marginally higher price point, are becoming an industry standard as a result of their superior characteristics.

Engine Oil Product Recommendations

Amsoil Inc. is arguable the most renowned name in the synthetic motor and gear oil marketplace. Founded in 1972, the company has been at the forefront of technology in the synthetic oil sector. Their line of diesel engine oils are specifically formulated to endure the severe conditions your engine oil encounters. Having used Amsoil products almost exclusively for more than a decade, we can attest to quality of their products and the protection they offer. By switching to Amsoil products, we've been able to document reduced fuel dilution, reduced oil consumption, prolonged turbocharger life (reduced journal bearing wear), and superior engine oil life.

Viscosity	Criteria Met/Special Specifications	Recommended Product(s)	Remarks
15W-40	API CK-4, CJ-4, CI-4, CF, CF-2 Cummins CES 20086, CES 20081 FCA MS-10902 Ford WSS-M2C171-F1	Amsoil 15W-40 Max Duty diesel oil	15W-40 is likely the most common oil viscosity used in on-highway diesel applications through the years. It generally is used in ambient temperatures above freezing, but is typically issued over a broad temperature range. Amsoil Signature Series Max Duty is a top tier diesel oil offering superior wear protection and resilience against thermal breakdown and chemical contamination. Meets most specifications for modern engines with EGR and exhaust aftertreatment systems.
		Amsoil 15W-40 Heavy Duty diesel oil	Economically priced, entry level full synthetic diesel oil offering advanced wear protection and excellent resilience against thermal breakdown and chemical contamination. May not meet all modern requirements in vehicles equipped with exhaust aftertreatment systems; recommend Max Duty (above) for vehicles equipped with DPF/SCR systems.
	API CI-4, CI-4+, CH-4, CF, CF-2, SL, SJ Cummins CES 20076, CES 20077, CES 20078	Amsoil 15W-40 Heavy Duty TBN 12 diesel oil	A high TBN 15W-40 diesel oil ideal for high mileage vehicles where blow-by, fuel dilution, and crankcase contamination is of high concern. An engine oil with a higher TBN (total base number) will neutralize a greater concentration of acids in the engine oil before the lube oil itself becomes acidic. Not for vehicles equipped with exhaust aftertreatment systems, but highly recommended in older vehicles, vessels, and equipment.
5W-40	API CK-4, CJ-4, CI-4, CF, CF-2 Cummins CES 20086, CES 20081 FCA MS-10902 Ford WSS-M2C171-F1	Amsoil 5W-40 Max Duty diesel oil	Premium full synthetic diesel oil that offers superior wear protection and maximum protection against thermal, mechanical, and chemical breakdown; meets most specifications required by modern exhaust aftertreatment systems.
		Amsoil 5W-40 Heavy Duty diesel oil	Economically priced, entry level full synthetic diesel oil offering advanced wear protection and excellent resilience against thermal breakdown and chemical contamination. May not meet all modern requirements in vehicles equipped with exhaust aftertreatment systems; recommend Max Duty (above) for vehicles equipped with DPF/SCR systems.
	API SN, SM GM LL-B-025	Amsoil 5W-40 FS Euro Spec diesel oil	Specifically formulated to meet European specifications, notably those required by the 2020+ EcoDiesel found in the Ram 1500.
5W-30	API CK-4, CJ-4, CI-4, CF, CF-2, SN+ Cummins CES 20086, CES 20081 FCA MS-10902 Ford WSS-M2C214-B1	Amsoil 5W-30 Max Duty diesel oil	Premium full synthetic diesel oil that offers superior wear protection and maximum protection against thermal, mechanical, and chemical breakdown; meets most specifications required by modern exhaust aftertreatment systems.
5W-30	GM DexosD, Dexos2, Ford WSS-M2C214-B1, FCA MS-11106	Amsoil 5W-30 synthetic diesel oil	Notably meets DexosD and Dexos2 specifications for various GM applications. Premium synthetic diesel oil that is compatible with exhaust aftertreatment and modern EGR systems.
10W-30	API CK-4, CJ-4, CI-4, CF, CF-2 Cummins CES 20086, CES 20081 Ford WSS-M2C171-F1	Amsoil 10W-30 Max Duty diesel oil	Premium full synthetic diesel oil that offers superior wear protection and maximum protection against thermal, mechanical, and chemical breakdown; meets most specifications required by modern exhaust aftertreatment systems.
10W-30	API CK-4, CJ-4, CI-4, CF Cummins CES 20086, CES 20081 Ford WSS-M2C171-F1	Amsoil 10W-30 Heavy Duty diesel oil	Economically priced, entry level full synthetic diesel oil offering advanced wear protection and excellent resilience against thermal breakdown and chemical contamination. May not meet all modern requirements in vehicles equipped with exhaust aftertreatment systems; recommend Max Duty (above) for vehicles equipped with DPF/SCR systems.
0W-20	GM DexosD	Amsoil 0W-20 Synthetic diesel oil	Notably meets GM DexosD requirements for the 3.0L Duramax diesel used in Silverado/Sierra 1500 applications. Premium synthetic diesel oil that is compatible with exhaust aftertreatment and modern EGR systems.
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