The Dorman 3.9" Base Diesel Engine Oil Cooler is the perfect replacement for your original equipment oil cooler. This oil cooler is made of durable, corrosion-resistant aluminum for reliable and leak-free performance. It provides a precise match for the fit and function of the original equipment oil cooler. Installing this oil cooler can improve the performance of your engine, making it a great choice for any diesel engine. FleetPride is your First Click in Heavy Duty®.