RUBIA WORKS 4000 10W-40 has been especially reinforced in viscosity stability under shearing and oxidation resistance (much higher than simple API CK-4), providing the possibility for the end user to reach or to exceed the maximum manufacturer’s drain interval recommendation, even under severe working conditions with bad Fuel quality or with Bio-Diesel fuel. Furthermore, it’s 10W-40 viscosity grade allows the end user to start the engine at very low temperature