Excessive Oil Leaking From Intercooler
 

03 S80, On driver side hose at the boot just inside of core support next to Dr side headlight there is a lot of oil coming from the ruber boot at clamp. Also the oil was changed bout 2-weeks ago and already one full qt low. My question is why so much oil in the ic, and what all could be causing this to happen. Other than that car runs smooth and quiet.

Clogged PCV or blown turbo.

Your turbo is allowing oil to pass the bearings into the cold (intake air) side. This is very common for high mileage turbos. I have 155k on my turbo which is still going strong and it does transfer a bit of oil, too. Most of this goes into the engine and is burned. The hose you are referring to may need to be tightened, as this is a vacuum/pressure leak. It is very easy to reach. Loosen the clamp and work the hose off the IC, then check for cracks in the plastic pipe. If it is cracked, short of replacing the pipe, I have successfully applied a patch of black RTV and several wraps of self-sealing rubber tape...a sort of cold vulcanizing. It worked perfectly! Re-connect the pipe and tighten the clamp securely. I have used this same method on the plastic induction pipes on top of the engine where they are blasted with heat. The repair looks good and unless one knows the S80 well, you would never detect the repair.

To check for a clogged PCV system, start the engine. Remove the oil cap (at idle only!). Place a stiff square of cardboard completely over the oil cap opening. It should be lightly sucked down and stay in place. If it blows off, you will need to service the oil trap and related hoses under the intake manifold.