Oil filler neck

When there is a pipe about eight to ten inches long, that is for better access when pouring in the oil. You should see that it attaches the same way the "oil" cap attaches. To say that a different way, the cap will screw on in place of the extension pipe. Just use a funnel the next time you add oil. If you go to one of the speedy lube places, they usually pump from a bulk oil tank through a really long nozzle that can reach the hard-to-reach fill ports.