During a visit to Redneck diesel performance, Todd, the owner, explained a unique check valve issue that affects the DD15 engine. When the check valve in the filter housing goes bad, it can allow the fuel system to lose prime. If this happens, the fuel system will need to be reprimed using the hand primer—causing delays and lost productivity. To make matters worse, the check valve is NOT replaceable—the entire filter housing must be replaced (expensive and time-consuming). With that in mind, we'