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AI-generated illustration of a generic diesel pickup towing a trailer loaded with secured lumber
AI-generated illustration of a generic diesel pickup towing a loaded trailer. Not an actual vehicle test or manufacturer photograph.

EPA27

Everything you need to know about the changes coming to diesel trucks due to the new regulations.

News. Reviews. Engineer Explains. Reliability.

Emissions Changes / EPA27

Understand EPA27 emissions requirements before sorting through the engine announcements. Start with the basics, then explore PUTT’s reporting on hardware, oil, maintenance and the questions still unanswered.

START HERE: EPA27 EXPLAINED

What changes, which trucks it affects, and why owners should care about cost, reliability and maintenance.

GM 8.3L Duramax and exhaust aftertreatment hardware
The 8.3L Duramax and exhaust aftertreatment hardware at GM’s powertrain event. (Video still: Tim Esterdahl)

EPA 27 explained: What truck owners need to know

The cornerstone guide separates commercial-engine rules from pickup requirements, explains DEF and warranties, and distinguishes final rules from proposals.

Read the EPA27 explainer →

ENGINEERING AND REAL-WORLD OWNERSHIP

See how manufacturers approach the emissions challenge. Commercial-truck hardware and pickup hardware are not automatically interchangeable.

GM 8.3L Duramax on display
GM’s new 8.3-liter Duramax on display with an engineer at the powertrain event. (Video still: Tim Esterdahl)

GM’s 8.3L Duramax

An announced pickup engine, explained with GM’s engineers.

Read story →

GM diesel engine and aftertreatment
The 8.3L Duramax and exhaust aftertreatment hardware at GM’s powertrain event. (Video still: Tim Esterdahl)

Two DEF injectors

A closer look at GM’s exhaust-treatment hardware.

Read story →

Detroit diesel in a Freightliner Cascadia
A Detroit Diesel DD15 engine in a Freightliner Cascadia (Photo by Aaron Turpen)

Daimler’s emissions engineer explains

Aaron Turpen interviews Daimler’s Dan Potter about commercial engines and emissions requirements.

Coming October 17: Aaron’s written article, “Daimler’s Gen 6 diesel: How Detroit is preparing for EPA 27,” explores the new Detroit engine family.

Watch the interview →

OIL, ENGINE PROTECTION AND EMISSIONS

Lubricant development is part of the durability story. A new oil category does not override an engine’s required viscosity, approval or service interval.

Shell presentation chart showing diesel oil categories and viscosities
Shell’s original slide shows viscosity grades in context; it is not a recommendation for every pickup. (Shell presentation photographed by Tim Esterdahl)

Oil viscosity and the Duramax: Is thicker oil better?

DEF expiration, storage and emissions problems explained

CONFIRMED NEWS AND WHAT COMES NEXT

An announced engine, an oil-test result and an editorial prediction carry different levels of evidence.

A test engine or proposed oil specification does not confirm a new production pickup engine. Look for a manufacturer announcement naming the engine, application and timing before treating a forecast as fact.

Explore all Emissions Changes coverage →