AMSOIL Signature Series Max-Duty Synthetic Diesel Oil 5W-40
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Signature Series Max-Duty Synthetic Diesel Oil 5W-40Help

Maximum-duty protection for your hardest-working diesel engines

Signature Series Max-Duty Synthetic Diesel Oil 5W-40 Product Image
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$11.50 Retail Price (USD)
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Product Code: DEOQT-EA
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Protect your investment in diesel power and confidently extend drain intervals with our top-grade synthetic diesel oil. AMSOIL Signature Series Max-Duty Synthetic Diesel Oil delivers 6X better wear protection than required by the Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222. Advanced synthetic technology provides excellent viscosity control and outstanding extreme-temperature performance, while minimizing oil consumption. The result: protection that’s boosted to the max.

Maximum Engine Protection
Wear on rings and cylinder liners leads to increased oil consumption and loss of compression, resulting in reduced horsepower and fuel economy. Independent testing shows AMSOIL Signature Series Max-Duty delivers 6X more wear protection than required by the Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222, delivering the security of providing your diesel the extra protection it deserves.

Viscosity Control
Using top-tier synthetic base oils, AMSOIL Signature Series Max-Duty is naturally resistant to oxidation and the thickening effects of soot contamination. That, along with boosted detergent/dispersant additives, keeps soot particles suspended independently, helping prevent the formation of larger, wear-causing particles. Viscosity increase is minimized and soot-related wear is controlled. Lower volatility also helps Signature Series Max-Duty retain its viscosity after high-temperature service for maximum engine protection and efficiency.

Excels in Extreme Temperatures
AMSOIL Signature Series Max-Duty Synthetic Diesel Oil resists thermal (heat) breakdown better than conventional and competing synthetic diesel oils. Unlike conventional oils, Signature Series contains no wax, staying fluid in sub-zero temperatures for easier starting, improved oil flow and reduced wear.

Minimizes Oil Consumption
AMSOIL Signature Series Max-Duty has a low rate of volatility (burn-off), reducing oil consumption during operation and passing less oil vapor into the combustion chamber. It provides up to 76 percent less oil consumption than required by the API CK-4 standard in the Caterpillar-1N oil consumption test.

Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222
Oil Consumption

APPLICATIONS
Use in diesel engines and, where appropriate, gasoline engines requiring any of the following specifications:

  • API CK-4/SN, CJ-4, CI-4+, CF
  • Volvo VDS4.5, VDS4, VDS3
  • Mack EOS-4.5, EO-O
  • Renault RLD-4, RLD-3
  • Cummins CES20086, CES20081
  • Caterpillar ECF-2, ECF-3, ECF-1-a
  • DDC 93K218, 93K215, 93K214
  • DFS 93K222
  • ACEA E9, E7
  • MB 228.31
  • MAN 3575
  • MTU Type 2.1, II, I
  • JASO DH-2
  • Allison TES439
  • Deutz DQC III-10LA
  • Scania LA-2
  • Chrysler MS 10902
  • Ford WSS-M2C171-F1

Official Oil

COMPATIBILITY
AMSOIL Signature Series Max-Duty Synthetic Diesel Oil is compatible with other conventional and synthetic engine oils. Mixing AMSOIL diesel oils with other oils, however, will shorten the oil’s life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.

Aftermarket oil additives are not recommended for use with AMSOIL synthetic diesel oils.

SERVICE LIFE
Diesel Engine Service Life
Heavy-Duty On-/Off-Road: Three times (3X) OEM1 recommendation, not to exceed 60,000 miles/600 hours or one year, whichever comes first.

Turbodiesel Pickup: Two times (2X) OEM1 recommendation, not to exceed 25,000 miles or one year, whichever comes first.

Gasoline Engine Service Life
Two times (2X) OEM1 recommendation, not to exceed 15,000 miles or one year, whichever comes first.

Drain intervals may be extended further with oil analysis.

1Refer to your owner’s manual for OEM drain interval recommendations and guidelines for severe and normal service.

Note: Extended drain intervals are not recommended for performance-modified engines, when using biofuels containing more than 10 percent ethanol or 15 percent biodiesel (B15) or for 2007-2009 Caterpillar* C13 and C15 on-highway engines. Extend drain intervals beyond OEM recommendations in these instances only with oil analysis. Note: 2007-2010 Dodge**, Ford** and GM** turbodiesel pickups are also not recommended for extended drain intervals when using DHD.

HEALTH & SAFETY
This product is not expected to cause health concerns when used for the intended application and according to the recommendations in the Safety Data Sheet (SDS). USA and Canada (M)SDS are available upon request at 715-392-7101 or on the AMSOIL Website. Keep Out of Reach of Children. Don’t pollute. Return used oil to collection centers.

AMSOIL PRODUCT WARRANTY
AMSOIL products are backed by a Limited Liability Warranty. For complete information visit www.amsoil.com/warranty.aspx.

* All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are developed by AMSOIL for use in the applications shown.

DEO Package Sizes
Code Package Size Unit of Measure Product
DEOQT (DEOQT-EA) Quart Each Premium 5W-40 Synthetic Diesel Oil
DEOQT (DEOQT-CA) Quart Case of 12 Premium 5W-40 Synthetic Diesel Oil
DEO1G (DEO1G-EA) Gallon Each Premium 5W-40 Synthetic Diesel Oil
DEO1G (DEO1G-CA) Gallon Case of 4 Premium 5W-40 Synthetic Diesel Oil
DEOTP (DEOTP-EA) 2.5-Gallon Each Premium 5W-40 Synthetic Diesel Oil
DEOTP (DEOTP-CA) 2.5-Gallon Case of 2 Premium 5W-40 Synthetic Diesel Oil
DEO30 (DEO30-EA) 30-Gallon Drum Each Premium 5W-40 Synthetic Diesel Oil
DEO55 (DEO55-EA) 55-Gallon Drum Each Premium 5W-40 Synthetic Diesel Oil
DEO27 (DEO27-EA) 275-Gallon Tote Each Premium 5W-40 Synthetic Diesel Oil
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REVIEW SNAPSHOT®

by PowerReviews
AMSOILSignature Series Max-Duty Synthetic Diesel Oil 5W-40
 
4.9

(based on 117 reviews)

Ratings Distribution

  • 5 Stars

     

    (108)

  • 4 Stars

     

    (7)

  • 3 Stars

     

    (1)

  • 2 Stars

     

    (1)

  • 1 Stars

     

    (0)

98%

of respondents would recommend this to a friend.

Most Liked Positive Review

 

The best oil out there!

I use Amsoil in my 2015 F-250. This oil holds up under the stresses that come with running 11 hrs. a day 5 days a week in commercial use. My 2015 already...Read complete review

I use Amsoil in my 2015 F-250. This oil holds up under the stresses that come with running 11 hrs. a day 5 days a week in commercial use. My 2015 already has 155k miles on it thanks to Amsoil, without any engine problems. I have tried other oils, even Royal Purple Duralec, but none compare to the 15-40's strengths when under the high temperatures of Summer in the south and the cold temperatures of the north in Winter.

VS

Most Liked Negative Review

 

Not sure for the Fords...

First, I'll say that I love Amsoil. I run Amsoil in every engine/transmission/differential/etc I own. I'm not sure about this new oil. My oil temp in a Ford 6.7 Powerstroke...Read complete review

First, I'll say that I love Amsoil. I run Amsoil in every engine/transmission/differential/etc I own. I'm not sure about this new oil. My oil temp in a Ford 6.7 Powerstroke usually runs about 203 degrees (previous version of Amsoil diesel oil). With this new oil (December it might have come out???) I'm running 7-10 degrees hotter on average. I'll probably try one more oil change with it and if it still runs hotter, I'll have to find another brand.

Reviewed by 117 customers

Displaying reviews 1-10

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2.0

Not sure for the Fords...

By 

from San Diego, CA

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 5W-40:

First, I'll say that I love Amsoil. I run Amsoil in every engine/transmission/differential/etc I own. I'm not sure about this new oil. My oil temp in a Ford 6.7 Powerstroke usually runs about 203 degrees (previous version of Amsoil diesel oil). With this new oil (December it might have come out???) I'm running 7-10 degrees hotter on average. I'll probably try one more oil change with it and if it still runs hotter, I'll have to find another brand.

  • How would you describe yourself?:
  • I'm a full-on gearhead
  • What kind of vehicle/equipment do you have?:
  • Ford F450
 
5.0

Extended oil life, runs cooler

By 

from Calgary, Alberta

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 5W-40:

I am astonished at the engine oil life provided by this oil, compared to the Mobil synthetic I used previously. I'm at 14000 km, 80% city, and the computer is telling me I still have 20% oil life. Previously I would get to about 10k and be looking to change. Admittedly I changed to Wix filter at the same time from Oem, so not a 100 % true comparison. Winter, with more idling, will be the real test. Engine seems to be running cooler even in 30C weather- that's hot for us!

  • How would you describe yourself?:
  • I'm a DIY handyman
  • What kind of vehicle/equipment do you have?:
  • 2014 Ram 1500 Ecodiesel
 
5.0

Simply the BEST better than all the rest ! ! !

By 

from BUCKEYE, ARIZONA

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 15W-40:

I have a 2011 Chevy one ton dually long bed . Now over 100,000 miles and is running great I feel because I have used Amsoil since day one . I have used every brand with prior vehicles and always go back to Amsoil.

  • How would you describe yourself?:
  • I use AMSOIL products for my business
  • What kind of vehicle/equipment do you have?:
  • All kinds
 
5.0

Great oil

By 

from Heber,Az

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 5W-40:

Use it a 09 Chevy Duramax, starts great even if it hits 0 or below

  • How would you describe yourself?:
  • I love my vehicles / toys
  • What kind of vehicle/equipment do you have?:
  • 2009 Chevy 4x4 2500hd ext cab
 
5.0

Love your products!

By 

from Surf City, NC

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 15W-40:

Buy diesel, gas oil plus PI for my gas vehicles. Amsoils is the best!

  • How would you describe yourself?:
  • I love my vehicles / toys
  • What kind of vehicle/equipment do you have?:
  • GMC, Acura, Land Rover & Honda
 
5.0

I would definitely buy this product again

By 

from Toronto, Ontario Canada

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 5W-40:

I currently use this product on my 2016 Ram EcoDiesel with no issues and have use the previous 5W40 diesel product on previous diesel pick up trucks and heavy-duty equipment with no complaints. Thank you Amsoil.

  • How would you describe yourself?:
  • I love my vehicles / toys
  • What kind of vehicle/equipment do you have?:
  • 2016 Ram 1500 EcoDiesel
 
5.0

Repeat purchase

By 

from OR

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 15W-40:

Been using Amsoil HD Diesel oil for many years in Ford Turbo SDuty. Best oil out there!

  • How would you describe yourself?:
  • I'm a professional mechanic
  • What kind of vehicle/equipment do you have?:
  • Ford Super Duty, Ford Explorer V6.
 
5.0

I only use Amsoil

By 

from Mesquite NV

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 15W-40:

I'm running the 15w-40 Amsoil Signature Diesel in my Corvair air cooled engine in my 22 foot RV. Very heavy duty use for a 3 liter engine from the '60's, and it performs perfectly, along with the Amsoil 75w90 Severe Gear in my differential, and Amsoil ATF in my Powerglide transmission. I use nothing but Amsoil products in my 17 Prius, the 16 Subaru Forester Turbo, And every car I have owned in the last 15 years, and will continue to do so.

  • How would you describe yourself?:
  • I'm a full-on gearhead
  • What kind of vehicle/equipment do you have?:
  • Antique RV, Corvair, Subaru SUV, prius
 
5.0

I only use Amsoil products.

By 

from Columbus ohio

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 15W-40:

I like to take extra care of cars that I love. For those cars, I only use Amsoil products. Why? I trust and appreciate the information and research they provide. I'll pay extra for that trust.

  • How would you describe yourself?:
  • I'm a DIY handyman
  • What kind of vehicle/equipment do you have?:
  • Ram diesel and Dodge Charger RT.
 
5.0

Great stuff

By 

from Alberta and B.C.

Verified Buyer

Comments about Signature Series Max-Duty Synthetic Diesel Oil 15W-40:

Best oil out there. Installed a bypass filter system as well. Very happy with all aspects. Installation was simple

  • How would you describe yourself?:
  • I'm a DIY handyman
  • What kind of vehicle/equipment do you have?:
  • Longhorn 3500/2015

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