15W-40 Commercial-Grade Diesel Oil Product Code : SBDFTP-EA • Greater than 50% synthetic content delivers upgraded protection • Delivers 2X more wear protection1 • Helps keep trucks and equipment operating at peak performance • Excels in temperature extremes • Provides outstanding value and excellent protection for customers seeking an upgrade over other synthetic-blend and conventional diesel oils
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL 15W-40 Commercial Grade Diesel Oil.
AMSOIL 15W-40 Commercial Grade Diesel Oil (SBD) is an advanced synthetic-blend heavy-duty diesel oil with greater than 50 percent synthetic content. The 15W-40 grade is the workhorse fleet viscosity for on-road and off-road service, and the Commercial-Grade tier is built for trucks, agricultural and construction equipment, and stationary diesels whose owners want stronger protection than conventional oil at a fleet-friendly price point.
Wear protection backed by DD13 scuffing test
Wear on rings and cylinder liners drives oil consumption up and pulls horsepower and fuel economy down. Commercial-Grade Diesel Oil delivers 2X more wear protection than required by the Detroit Diesel DD13 Scuffing Test for specification DFS 93K222, based on third-party testing using 10W-30 as a worst-case representation. The 15W-40 grade records a 0.46 mm wear scar in the Four-Ball Wear Test (ASTM D4172). Together the two results show a synthetic-blend formula that holds up to the wear loads heavy-duty diesel service produces.
Viscosity control and soot dispersancy
Greater than 50 percent synthetic base oil content, paired with high-performance detergent and dispersant additives, holds operating viscosity stable as the oil accumulates soot, fuel dilution, and heat. The dispersants keep soot particles suspended independently, preventing the formation of the larger agglomerates that grind on liners, lifters, and rings. The 15W-40 grade carries a viscosity index of 141, an HTHS viscosity of 4.6 cP (ASTM D5481), and a Total Base Number of 10.0 (ASTM D2896), providing reserve alkalinity to neutralize acidic combustion byproducts through the drain interval.
Heat resistance and cold-start flow
Commercial-Grade Diesel Oil is formulated to deliver improved heat and oxidation resistance compared with conventional and other synthetic-blend diesel oils, helping maintain power and fuel efficiency through extended duty cycles. At the other end of the temperature range, the 15W-40 grade flows dependably in cold weather for reliable startup and lubrication. CCS viscosity is 5,226 cP at -20 C (ASTM D5293), pour point is -36 C (ASTM D97), and flash point reaches 238 C (ASTM D92).
Low volatility and combustion-chamber cleanliness
A low rate of volatility means less of the oil burns off through normal operation. NOACK volatility for the 15W-40 grade comes in at 4.6 percent weight loss (ASTM D5800), reducing oil consumption, passing less oil vapor into the combustion chamber, and contributing to fewer combustion-chamber deposits. Lower oil-vapor carryover also supports the diesel particulate filter, EGR system, and other aftermarket emissions hardware over the long haul.
Heavy-duty OEM and industry coverage
Commercial-Grade Diesel Oil is built for fleet engines that call for current heavy-duty diesel categories where the formula qualifies. Check the live AMSOIL product page and your equipment manuals for the current approval list before using one formula across a mixed fleet of on-road tractors, vocational trucks, and off-road equipment.
Recommended applications and service guidance
Use the live AMSOIL product page and your owner's manual to confirm the current viscosity, API category, OEM approvals, and service guidance for your engine before ordering. AMSOIL updates approvals and recommendations as formulas and manufacturer requirements change.
For extended service, follow the current AMSOIL guidance, your equipment manual, and oil-analysis results. Extended intervals are not appropriate for every engine or operating condition, especially modified engines, unusual fuels, racing use, or equipment with special service restrictions.
Typical technical properties
Property
Value (SBDF 15W-40)
Kinematic Viscosity at 100 C, cSt (ASTM D445)
15.2
Kinematic Viscosity at 40 C, cSt (ASTM D445)
112.1
Viscosity Index (ASTM D2270)
141
CCS Viscosity, cP at -20 C (ASTM D5293)
5,226
Flash Point, C (ASTM D92)
238
Fire Point, C (ASTM D92)
248
Pour Point, C (ASTM D97)
-36
Four-Ball Wear Test scar, mm (ASTM D4172)
0.46
NOACK Volatility, percent weight loss (ASTM D5800)
AMSOIL 15W-40 Commercial Grade Diesel Oil is available in gallon jug (SBDF1G-EA), case of four gallons (SBDF1G-CA), 2.5 gallon jug (SBDFTP-EA), 55 gallon drum (SBDF55-EA), and 275 gallon tote (SBDF27-EA), giving fleet operators a clear path from single-truck shop service up to bulk on-site delivery. Using AMSOIL synthetic lubricants and practicing extended drain intervals does not void a new vehicle or equipment manufacturer warranty, and all AMSOIL lubricants and filters are covered by the AMSOIL Limited Warranty. Confirm engine application match with the AMSOIL Vehicle Lookup Guide, compare 15W-40 options across the diesel family with the AMSOIL Diesel Oil Guide, then order AMSOIL 15W-40 Commercial Grade Diesel Oil.
Doesn't really get any better than amsoil, been running the product for years in all of my modified vehicles front to back with no issues. The price of this 15w40 is on point as well.
By Joseph on December 15, 2025.
Would recommend this to a friend.
It’s a synthetic blend but …
It’s a synthetic blend but it’s a higher content blend than the rest. All my company trucks run it and it seems to working out great for all of them. Better fuel mileage and better engine temperatures!
By Paul H. from Joplin, MO on June 30, 2025.
Would recommend this to a friend.
My 6.0 loves it
Run this in my 2006 6.0 power stroke. Seems to be a better alternative to the OEM oil. Engine runs quieter and starts better. Zero injector issues.
Is AMSOIL Commercial Grade Diesel Oil a synthetic blend or a full synthetic?
Commercial-Grade Diesel Oil is an advanced synthetic-blend with greater than 50 percent synthetic base oil content. It sits between conventional diesel oil and a full synthetic such as AMSOIL Heavy-Duty Synthetic Diesel Oil or AMSOIL Signature Series Max-Duty Synthetic Diesel Oil, giving fleet operators a value tier with stronger wear protection and viscosity stability than conventional oil at a price point closer to conventional product.
Is 15W-40 only for diesel engines?
15W-40 is the workhorse heavy-duty diesel grade, but the Commercial-Grade application list also covers gasoline engines that specifically require a 15W-40 in API CF service, which is common in older gasoline pickups and farm equipment with mixed gas and diesel fleets. Always match the engine manufacturer service category before changing oil, and match the right product with the AMSOIL Vehicle Lookup Guide.
How often should AMSOIL Commercial Grade Diesel Oil be changed?
Commercial-Grade Diesel Oil is recommended for the drain interval stated by the original equipment manufacturer. The owner manual is the controlling document for the specific change interval on a given engine. Intervals may be extended beyond the OEM recommendation only with oil analysis, which is the right way to dial in a longer drain in mixed-duty fleet service.
How do I confirm current approvals?
Confirm the current API category, OEM approvals, and viscosity guidance on the live AMSOIL product page before service. Approval lists can change when formulas or manufacturer requirements are updated.
Can Commercial Grade Diesel Oil be mixed with conventional or other synthetic diesel oil?
The formula is compatible with other conventional and synthetic engine oils, but mixing reduces its performance benefits. Aftermarket oil additives are not needed or recommended for use with AMSOIL diesel oils. A clean fill of one product is the way to capture the full wear-protection and viscosity-stability benefit.
How does Commercial-Grade compare to Heavy-Duty and Signature Series Max-Duty?
Commercial-Grade (SBD) is a synthetic-blend value tier with the conservative claim of 2X more wear protection than the DFS 93K222 standard. AMSOIL Heavy-Duty Synthetic Diesel Oil (ADP) is a full synthetic with stronger extreme-temperature protection. AMSOIL Signature Series 100% Synthetic Max-Duty Diesel Oil is the top-tier line with the longest extended-drain capability and the highest tested wear protection. Compare the three families viscosity-by-viscosity with the AMSOIL Diesel Oil Guide to pick the tier that fits the fleet's duty cycle and budget.
Does running Commercial Grade Diesel Oil affect a new diesel engine warranty?
No. Using AMSOIL synthetic lubricants and practicing extended drain intervals does not void a new vehicle or equipment manufacturer warranty. All AMSOIL lubricants and filters are covered by the AMSOIL Limited Warranty.
