Where do you put supercharger oil in a Pontiac gtp?

The supercharger oil reservoir on a Pontiac GTP (referring to the supercharged 3800 Series II engine) is not directly filled. It's a sealed system. The oil is added through a specific fitting on the supercharger itself, not a separate reservoir like you might find on some other cars. You will need to remove the supercharger's inlet tube to access this port.

Crucially: Adding supercharger oil is not a routine maintenance item like changing engine oil. It's only done when the supercharger is serviced or rebuilt, usually by a qualified mechanic. Improperly adding or servicing the supercharger oil can damage the unit.

Instead of trying to add oil yourself, if you suspect a problem with your supercharger oil, it's best to consult a mechanic specializing in supercharged vehicles or your local Pontiac specialist. They have the proper tools and knowledge to check the oil level and perform any necessary maintenance.