an alternative fuel system and compressed natural gas conversion kit , primarily for smaller size industrial vehicles , such as compact loaders and lift trucks restricted in the space available in the engine compartment for the components of a cng system where the vehicle was initially engineered for other fuel systems such as gasoline liquid petroleum gas or diesel fuel having substantially fewer parts and components and less complex systems . a cng tank is mounted horizontally outside of the engine compartment and a high pressure line connects from the tank to a regulator mounted inside the engine compartment for decompressing the gas to a pressure suitable for mixing with air in the carburetor of the engine . the cng system has a refilling receptacle with an electrical interlock to the ignition preventing accidental drive - away . within the engine compartment , a mounting arrangement takes advantage of limited space and more efficiently transmits heat from the engine cooling system to counteract the refrigeration effect due to gas decompression in the components of the system . the arrangement outside the engine compartment utilizes guarding structures to protect the high pressure lines , valves , and fittings from damage , including taking advantage of the existing vehicle structure to prevent damage from hazards in the workplace during normal operation of the vehicle .