I have a 1997 Ski Doo Formula 3 and its leaking oil. I can see a drip at the bottom of the filter but don't know if it is the filter or the clamps or the hose. It is behind the exhaust so too hard to to work on it. I looked at trying to remove the oil tank (which looks like the coolant tank is part of it) but can't get to the bolts. How do you get the gas tank cover off? It looks to be riveted on.