Keeping your Duramax diesel engine cool, especially when you’re towing heavy objects or pushing for more power, is a big deal for engine life and performance. Legendary tuner Gale Banks recently took a deep dive into how General Motors (GM)’s Duramax oil coolers have changed over the years.

His video showed how owners of older trucks can get the latest cooling upgrades. He also highlighted the often-overlooked importance of this key component. The video explained that in these coolers, engine oil circulates through a stack of internal plates while engine coolant flows around them in the housing, pulling heat away.

Banks pointed out that early LB7 Duramax engines (from 2001) started with oil coolers using just 11 copper plates. By the time the L5P Duramax generation arrived, specifically models from around 2017-2019, GM had increased this to 14 plates.The real jump in cooling technology, according to him, came with the 2020 and newer L5P Duramax engines. These latest factory coolers pack between 17 and 19 plates (with the current 2025 L5P units featuring 19 plates) for much greater cooling surface area.

Additionally, these newer designs incorporate a larger water inlet opening in the housing, greatly improving coolant flow through the unit. The main goals behind these factory improvements were to reduce oil pressure drop through the system and, most importantly, to cool the oil more effectively.

Seeing these factory advancements, Banks Power developed an Oil Cooler Upgrade Kit. This kit is directly based on the latest 2020-2025 L5P oil cooler design. Banks Power bundles all the necessary, often hard-to-find, parts into a single box.

This allows owners of earlier 2001-2019 Duramax trucks (covering LB7, LLY, LBZ, and LMM engine codes) to retrofit this superior, current-generation cooling technology onto their vehicles. It might just be an oil cooler, but according to Gale Banks, it’s an important part for keeping a Duramax diesel running strong and healthy.

For owners of earlier models, stepping up to the newest factory cooling technology, as made easier by comprehensive kits, offers a way to enhance their engine’s oil temperature regulation. So, when your engine is always working its hardest, always remember that better cooling means better protection and efficiency.