Change oil in supercharger

How do you change the oil in the supercharger on a 3.8 Monte Carlo
Asked Oct 05, 2013
3800 Series II 3.8L S/C:
The first step to changing the supercharger oil is to remove the engine cover by unscrewing the bolt just above the "3800 Series II Supercharged" text on the cover. Also remove the engine oil crankcase filler cap.

Then locate the snout of your Eaton M90 or M112 supercharger and the belt that goes around the pulley. The stock pulley on a Pontiac Grand Prix GTP is 3.8". By putting on a smaller pulley you can force the supercharger to spin faster and produce more boost and hp. The stock boost rating of my M90 is 6 lbs (pounds).

Next, get your two 4 oz (ounce) bottles of GM Vehicle Care Supercharger Oil, which is part number 1 # 12345982 at any GM dealership or at online retailers. You'll also need a sprayer top and some sort of bottle to hold the old supercharger oil. The old oil will really stink so be prepared for that.

GM Supercharger Oil
Once you remove the bolt, you can insert your totally clean and dry spray bottle pump head tube. (You don't want to introduce any water or foreign substances into the supercharger oil reservoir chamber.)

Supercharger Oil Tank Bolt
Once you get most of the oil pumped out of the supercharger, try to move the pump's hose around to get any more that is hiding in the crevices of the M90. Then you just have to use a small funnel and carefully fill the supercharger up with oil to just under the bolt threads. Don't Overfill Your Supercharger!
Answered Oct 06, 2013

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