Copied from the Midlana forum (link above):
So as big things get solved (intercooler ducting, ECU retune, drivability, etc.), issues previously less-important have bubbled to the top of the list.
After installing Engine V2.0, an oil leak was found under the engine, unfortunately traced to one edge of the front cover. I say “unfortunately” because on a Honda K-series engine, the front cover is trapped by the oil pan and cylinder head. Even if I got it out without destroying the head or pan gasket, there’s no way I’d get it back in, and I’m loath to remove the pan and head! Neither gasket in those areas are critical but it would most certainly introduce new oil leaks.
What’s interesting is how the dripping only happens with the engine is not running. Due to running a dry sump oil system, a side perk of it is that it pulls a vacuum in the crankcase which prevents any oil from leaving! The puzzling thing is that just sitting there it drips a fair amount of oil. Over the last six months or so, it’s filled the drip pan on the floor about half way. With the leak along one edge of the front cover, it’s fairly high up on the engine, so where the heck is all the oil coming from? I’d expect that as soon as the engine’s shut down, the hot oil in the head and front cover would quickly find its way back to the pan, and yet there it is on the floor.
So the challenge is how to fix it in-place and what *might* work is to take advantage of the dry sump’s vacuum. That is, apply gasket sealer along the suspect area, then drive for an hour or so. The idea is that the vacuum will draw the sealer into the leak, and the heat will cure it relatively fast. The trick is finding a low viscosity gasket sealer that gets drawn easily into cracks, which seems unlikely, so I’ll probably be stuck with whatever’s available. That said, if it’s too low a viscosity, it’ll get entirely sucked in and not seal anything; water-thin is too far in the other direction. I guess the first thing is to double-check that the leak’s coming from where I think it is.
Thanks to reader Bill who said “maybe it’s time for some UV dye and a UV lamp.” Well, huh, I had no idea such a product existed, and ordered AC Delco 4-In-1 Fluorescent Dye, PN 10-5045, and it’s affordable. During our discussion, it occurred to me that the leak at the front cover might be a red herring, that maybe there’s a second larger leak lower down. The plan is to add the dye, run the engine until warm, then shut it off and watch and wait. The instructions say that the dye can be left in the system without harm, but for peace of mind, the oil will be changed after the leak source is found and fixed.