General Motors recently announced the 3.0L LZ0 Duramax Diesel, which is the second generation of the inline 6-cylinder turbo Diesel engine Chevrolet introduced in 2019. The engine will be on select 2023 Chevrolet Silverado 1500 and 2023 GMC Sierra 1500 trim levels, and will have even greater availability by the 2024 model year, as MC&T first reported. The GM Duramax diesel engineers were able to put in some considerable work on the engine to upgrade its performance, with around 25% of the parts different from the first generation, with power now coming in at an upgraded 305 hp and 495 lb-ft of torque. But while performance has been increased, reliability is also said to be improved.
3.0L Duramax Diesel Improvements From LM2 To LZ0
According to an interview with GM diesel engineer John Barta over at Pickup Truck + SUV Talk, GM has extended the LZ0 Duramax Diesel inspection recommendation to 200,000 miles, meaning that customers can now drive the truck for quite some time before inspecting the belt. This is fantastic since the location of the belt requires you to drop the transmission to check it. Additionally, there was an issue with the previous engine, which had reports of a long crank and either a slow-start or no-start event. If you waited and then tried again, the truck would eventually start.
It turns out this was a complex problem to track down, but eventually, it was concluded that the culprit was an exciter wheel with bent teeth from a supplier, which would trick the system into thinking it wasn’t operable. So GM fixed the supplier issue and changed the engine crank to allow the teeth to better engage in both the LM2 and LZ0 Duramax engines.
As for other parts changes, the LZ0 Duramax also uses steel pistons compared to aluminum pistons in the outgoing LM2 Duramax. The measurements are also different, with the new steel ones fitting in a narrower cylinder, thus allowing for a longer stroke to maintain displacement. There are also new injectors in the LZ0 compared to the LM2, allowing for improved turbocharger tuning to boost the power numbers. The cylinder heads have also been changed out, and improvements have also been made to the cooling system. Fuel economy has not been announced at this time.