I was replacing the radiator due to leaking at the upper neck - could be due to worn rubber gasket or warped plastic parts. The car is a 2006 MCS with 133,000 miles.This is the 3rd radiator so far. The second one failed due to a small object (maybe a small rock) hitting the core while driving on the freeway.

Anyways I decided to check the supercharger oil at the front port next to the engine oil filler tube. I found that it was not full as no oil came out when I removed the plug. I then got worried and decided to check the other port which is at the water pump side of the SC. As everyone knows, it is very hard to impossible to get to that port without having to remove a lot of parts. All of my readings indicate that I have to remove the SC itself to be able to access that port. Well, I was not ready to disassemble all the way to the water pump. I did this a couple of years back and has held without any leak so far. I then proceeded to remove the upper air hose, the throttle body, and the lower air hose to gain access to the SC port at the water pump. To my surprise, there was adequate room to get to that port in question. I have attached some pics for your reference. So there you go. You can access the port at the back of the SC without having to remove the SC itself.

But that is not the end of my story. Once I removed the plug, oil started to flow out like it has been overfilled. It was not just oozing out, but was flowing out rapidly. I then put the plug back and left it alone. Going back to the other port, I was able to put in 4 OZ of GM12345982 to fill it up till oil started to flow out. So now I am not sure whether both ports are filler ports. If you compare the relative location of both ports, the one in front is higher than the one at the water pump side. So is it possible that the front port is the filler port and the one at the water pump side is the drain port?

 

No.
There are two chambers, one in front and one in the back (water pump PTO).
They are in no way connected.

 

And to fill it properly...
The sc must be off, and tipped....or oil runs out the hole...THAT IS WHY it MUST be removed to check/fill the oil...
I have a spare sitting down in the garage...and I can say with 100% certainty... The two oil locations are not connected....if they were...the upper would run dry first... But THAT one can be checked simply...