Tufoil Engine Treatment For Trucks 50 oz. Tufoil Truck Engine Treatment is specially packaged in a handy 50 oz size container for the heavy-duty engine with a 25-32 quart crankcase capacity Tufoil Truck Engine Treatment is added to your clean oil at the time of the oil change It will provide the motor oil with the performance enhancement needed to make the engine start easier, run cooler, produce more horsepower, increase gas mileage and ultimately extend the life of the engine Large diesel trucks are expensive to run and very costly to repair