The caps of different parts in the engine have different functions. The engine radiator cap allows the coolant to maintain a certain pressure, preventing damage to the hoses and radiator. The oil cap helps the oil reservoir to have a good sealing effect. The diesel fuel cap protects the fuel in the tank from contamination.
MyMRO has different types of replacement radiator caps, oil caps and fuel caps for sale at less cost. You can buy high performance aftermarket radiator caps, oil caps, fuel caps here of various brands, such as Cummins, Perkins, Bobcat, CAT Caterpillar, Hitachi, John Deere, Komatsu, Kubota, etc.