Chevrolet Duramax (badge, not an engine)
turbocharged · diesel · 2001–present
Also known as: duramax, duramax diesel
Duramax is a badge, not an engine. General Motors uses it for its diesels, and our rows show it across Chevrolet, GMC, Cadillac and Hummer — from a 1.6 four in the small crossovers to the 6.6 V8 in the heavy pickups.
The 6.6 V8 is what most people mean, and it is worth knowing that it is an Isuzu design — built by a GM–Isuzu joint venture, which is why some of its service literature reaches back to Isuzu rather than to GM.
Establish the RPO code, which is on the engine and in the build sheet: LB7, LLY, LBZ, LMM, LML, L5P for the 6.6, and quite different letters for the small ones. The generation decides everything, because the injectors, the emissions equipment and the known faults all changed between them.
⚑ The LB7's injectors are the family's famous fault — they fail internally and dilute the oil with fuel, and because they sit under the valve covers the job is far larger than an injector change on anything else here. An oil level rising on the dipstick is the tell, and it is the same warning as on every diesel in this catalogue for a different reason.
The later LML and L5P carry SCR and AdBlue, so their limp modes are as often an emissions sensor as an engine fault.
Cars fitted with this engine
17 generations, across 4 makes. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.
Cadillac
Chevrolet
GMC
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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