92babyblue, the oil level sender would leak all the time since it senses the oil level in the oil pan, and is below the proper oil level. As they age the oil level senders tend to leak at the electrical connection. If you are going to change it yourself (as mentioned a simple DIY job) do it when changing oil, i.e. with the oil drained from the oil pan ... or you will have oil coming out of the hole in the left side the oil pan. Be sure to use a new gasket with the new oil level sender.

Normally the oil pan is not pressurized when the engine is running, unless the engine has worn piston rings that allow blow-by.

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Fred Hoelzle