Oil is the lifeblood of an engine, and in a hardworking diesel engine like the 2003-2007 Dodge RAM 5.9L Cummins, keeping that oil cool is essential to the engine's health. ---- A clogged or leaking oil cooler can reduce the oil's ability to transfer heat to the coolant, causing thinning and a loss of protection for critical engine components. Mishimoto proudly offers a stock-style replacement oil cooler with new seals. This replacement cooler will restore and improve your engine's oil cooling capabilities and protect it from unnecessary wear. ---- This cooler is a direct fit and provides all the cooling a daily driven 5.9L Cummins needs at an affordable price point. Like all Mishimoto products, this oil cooler is backed by our Mishimoto Lifetime Warranty for a lifetime of worry-free driving