There really is only one seal conditioner that works in the long term, and that was mentioned by
surgeon. ATP AT-205.
We've had a pair of Odysseys for years and years (a trio of them at one time). Both of our vans, a 2002 EX and a 2003 EX, developed significant rear main seal (RMS) leaks one winter. I was changing flattened cardboard boxes frequently to protect the driveway. One of the vans (my 2003 IIRC) was losing almost a shot glass of oil every day.


Somebody on this forum turned me towards ATP AT-205. I've always been skeptical of items like that, and group them into the same family of products that claim to be "engine rebuild in a can." I had nothing to lose other than about $10 per 8oz. bottle.
Long story short, it worked. This is not an overnight fix; it take hours of operating the engine for it to do its good work. In my case, one van responded over the next couple months, the one with the severe leak took longer. By early summer neither van was leaking.
I use it now as a preventative measure in all of our family vehicles, 4oz. per oil change (essentially, half of what ATP prescribes for fixing an active leak).
OF