This is a long story, so bear with me. But we bought our 1997 400DA three years ago. It's a freshwater boat with ~1400hrs on both engines. We had the after coolers removed and cleaned when we bought the boat, and baselined all fluids and filters. All the original hoses were replaced last off-season. The boat was basically mint with the exception of a leaking oil pan gasket on the port motor. This allowed us to get a pretty stellar deal, and we figured it was a fairly reasonable enough fix. Fast forward three years, and now we know the previous owner had the gasket replaced once, we've replaced it twice now, and there is still a leak in the exact same location that it's always been. The leak takes roughly 5-10 engine hours to start after each gasket replacement, and then it gets slowly worse over time. It only leaks under pressure; there is no leak when the engine isn't running. The oil drips off the heads of the three forward most bolts on the starboard side of the port motor (at least they're the three easiest bolts to reach on either engine!). So after trying a number of different things each time, our mechanic (certified CAT mechanic) is now pretty sure that we have a warped oil pan. When the gasket is new, it's sealed. But as it soaks up oil throughout the season it gets more saturated and eventually starts to leak. So it sounds like we're headings towards a full oil pan replacement. He is going to try to one last-ditch attempt to squeeze the flange with bronze washers on those bolts, but he's not optimistic that it will work. So I have a few questions for you guys who've been down this road before: if/when he has to pull the port completely up and out of the boat, what do you guys suggest I do while I have the room and access to work down there? Obviously the waste vent filter is an easy item to reach. But it would be a lot nicer if this were the starboard engine, lol. Anyone ever install a Cablemaster in that aft starboard corner where there's a ton of dead space? Does anyone have any other suggestions of things to try before we go all the way to a new oil pan? Any other ideas of what could be causing this pesky leak other than a warped oil pan? I'm just looking to hear other thoughts on my situation so I have more information before I proceed onto the next steps. Thanks guys!!