How do I determine where oil in intercooler is coming from?

[gbest]

Over the last 6 or so seasons, I'm getting quite a bit of oil accumulating in the intercooler of my 2011 RXTis.
This seems to have started after I had my charger rebuilt, I have 2 identical skis with similar hours, the other one has no oil, both chargers done by Jerry at about 100 hours, currently at about 170 hours.
Is this an oil seal, or blow by, what is the best way to pinpoint the issue?

[troyheb]

If I had a dollar, I would bet it is coming from your SC. Pull the hose coming off the SC going to the IC and see if it is full of oil.

[John's truck]

It’s been 6 years since your supercharger was rebuilt? It’s a 2 year interval. Rebuild your charger. Make sure your oil isn’t over filled. Take the intercooler out of the ski and clean it out with solvent or gasoline, rinse it and reinstall.