I need to refill my oil in my supercharger and i don't know where or how to do it?

I only know about one and that is the Rootes type blower fitted to the BMW Mini.
The blower oil change is part of the 100,000 mile service and the supercharger must be removed to drain the oil and refilled with a precise quantity of special oil at each end.

If there is good access it might be possible to suck out the old oil with a syringe but removal would be better as draining would be more effective.
There is no reason why the oil should not be changed more often...

Sorry to hear that. Few people know the supercharger has its own oil. It needs to be checked and refilled as the car ages.
There is a spring loaded belt tensioning device....you need a socket that fits the bolt (some have a square hole for a 1/2 breaker bar) you take the tension off the belt and slip the belt off the most convenient pulley.

The common fault is not keeping the oil level up or the right kind of oil clean and refilled.

Yes it can be low, check it and refill it using the proper oil. GM 12345982 ......the oil level plug is near the base of the snout. oil level should be a bottom of plug threads, right side, as you are looking at the SC from the right front wheel. No, you cant by pass it.

This is very smelly oil so make sure to be prepared with some latex gloves.... You should change this oil ever 50 to 75 thousand miles. To do this you need to turn out the hex plug on the snout of the M90 eaton charger. Take a pump from a lotion bottle that is clean and dip the tube allll the way into the hole(reservoir). Now pump the fluid out into a plastic jar of some sort. There will be aprox. 6 ounces of fluid in the snout housing. Refill with GM supercharger oil only!!

The oil should be changed every 30K miles according to the Pontiac manual.
However, it is best to change it sooner or whenever you don't know when the last change was done.

do u want to know to know what type of oil? here is the Ford number for that oil, it takes about 3 bottles to fill the supercharger up if the oil is changed.

Motorcraft supercharger oil XL-4 (4 oz. bottle)

There is seal kits.available for the.m 90 supercharger on the 3800 go to zzperformance.com youl find an eye.full off aftermarket and hard to find parts for the gtp.

first you need to diagnose it.

On the supercharger snout, located immediately to the right of the coil pack mounted closest to the supercharger, is the supercharger oil plug. It is a hex nut that uses a 3/8" allen wrench.

When the engine is cold, remove the plug. You can use any item of your choice that will create vacuum such as a siphon, a turkey baster or my favorite is a squirt bottle nozzle with about a 12" line on it.
Insert your hose into the reservoir hole and remove as much of the oil as you can. If you use the squirt bottle nozzle then if the hose is long enough then you should be able to "snake" the hose down into the reservoir almost the entire length of it by pushing the end of it toward a "1 o'clock" position if you are standing directly in front of the car.
Squirt the oil into another container. If your oil is the GM supercharger oil, it is animal fat based and biodegradable and can go in your regular trash.
Refill with GM supercharger oil or any other appropriate lightweight oil specified to meet requirement for the Eaton M90 supercharger. An equivalent oil can be purchased from www.zzperformance.com.
Fill the reservoir until the fluid reaches the bottom of the fill hole threads.

As an added note, if you lose the hex nut cap for the reservoir it isn't necessary to order a new one. A 7/8" fine thread bolt will fit perfectly but be careful not to torque more than 8ft/lbs with either the nut or bolt.