Diesel Oil · AMSOIL stock no. ADOQT-EA
Heavy-Duty 5W-40 100% Synthetic Diesel Oil
Heavy-Duty 5W-40 100% Synthetic Diesel Oil is a 100% synthetic formula developed for hard-working turbodiesel pickups and equipment — 4X better wear protection than required by the Detroit Diesel DD13 scuffing test, with low volatility that minimizes oil consumption.1
- 4X better engine wear protection than required by the Detroit Diesel DD13 scuffing test.1
- Minimizes oil consumption — low volatility (burn-off) with excellent film strength at high operating temperatures.
- 5W-40 is specifically designed for the demands serious turbo-truck enthusiasts put their diesel pickups through.
- Exceeds the latest API CK-4 specification.
1 Wear-protection comparisons are based on the requirements of the Detroit Diesel DD13 scuffing test.
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Your next step
- Confirm the fit. Open the vehicle list above and match your year and engine.
- Check the product page. Capacity, what it does, and the AMSOIL claim basis.
- Order from AMSOIL. Use any Buy link: it opens AMSOIL.com and credits Tuned Yota. Preferred Customer pricing is available only through registration; it is a paid membership.
Frequently asked questions
Will switching to AMSOIL synthetic diesel oil cause leaks?
No — synthetic oils do not cause engines to leak. AMSOIL diesel oils are fully compatible with modern seal materials and are formulated to condition seals, keeping them pliable. They're safe in both new and high-mileage engines.
What's the difference between Max-Duty and Heavy-Duty?
Both exceed the API CK-4 specification. Heavy-Duty delivers 4X better wear protection than required by the Detroit Diesel DD13 scuffing test; Signature Series Max-Duty delivers 6X, with reserve protection that allows extended drain intervals — it's the pick for hardcore enthusiasts and owners who want the best.
Can AMSOIL diesel oil be used in gasoline engines?
Signature Series Max-Duty is suitable for applications specifying API SN+ and earlier, making it ideal for mixed fleets. Check your owner's manual for the specified viscosity and rating.
Where can I buy Heavy-Duty 5W-40 100% Synthetic Diesel Oil?
Online from AMSOIL through Tuned Yota, an Independent Authorized AMSOIL Dealer in Lakeville, Minnesota: every "Buy" link on this site opens the product on amsoil.com, and the order ships from AMSOIL. Preferred Customer pricing is available only by registering as an AMSOIL Preferred Customer. You can also call (612) 406-7117 or email info@tunedyota.com to order through us.