If you have an oil leak on the back of the block that you just can't quite pin down, check the oil pressure sending unit. I personally always had a "moist" block backside- never all out dripping or pouring, but no matter how many engine gaskets I replaced, I was always seeping oil from someplace. I replaced the camshaft seal, crankshaft seal, balance shaft seal, distributor o-ring, valve cover gasket, rear main seal (while replacing my transmission), the oil pan gasket, drain plug washer (which you should do every oil change anyway), multiple oil filter brands, I pulled the block plug and replaced the washer, and coated it with Hondabond, and even used a mirror to check the head to block mating surface to rule out the head gasket. Alas, I always overlook the oil pressure sending unit because the block was dry around the threads. BUT, that is not where it leaks. The part that leaks is the back of the sensor, where plastic is crimped into metal. It requites a 24mm socket to remove, and when replacing it you should lightly coat the threads with Hondabond. I discovered this on a friends car that was GUSHING from that area- literally losing a quart a week or damn close- and my dad, being the old school mechanic he is, thought back to the "old days" that I generally discount as having no relevance, but I'll be damned, he was right this time. I honestly thought Honda sensors were beyond being able to fail in that way, and yet that seems to be what was wrong with mine, as after I replaced it, the back of the block has been completely dry. They are only ~$10 new at a parts store, and require little time and effort to replace, you simple lift the car and remove the oil filter and sensor wire for access. I used a used one from a 2000 Civic on my friend's car as he is piss poor, and they are an identical part, so they are highly interchangeable, I am guessing. There's really no need for them to be engine specific. I hope this helps someone else not pull their hair out and spend $100 on gaskets like I did- not that it was a bad thing, I now have greater peace of mind about the car. It was still nice to finally nail the root of the problem, a problem I am guessing is often misdiagnosed as oil filter runoff or a leaky oil pan gasket.