o ring or leaky washers or the seal but all three require the same tear down..drain radiator, trans cover which requires all new gasket set $22, pumps about $100. If you take the front elbow off you can see the i,peeler..if you can move it at all side to side or up and down your bears are going out and the oil seal might be damaged..if it's tight could be one of the other oil seal sources OR still the oil seal..
No matter what you are going to have to remove the cover to get to the o ring. Being that it's an 81 I would recommend going ahead and replacing the water pump and all the o rings. Like mentioned above, buy a OEM pump. After market is just setting you up for another change in a year or too. It's not a difficut procedure to do. Goldwingdocs.com has a great tutorial on how to do the change. Take your time and it will be a breeze to do.
On that waterpump I recommend Cyclemax.com, mine was$137.00 including shipping the pump itself was $123.00, however I'm in kentucky and their in Ohio so your shipping may be more, but it should still be less than the $166.00 dealer cost and that's not includingsales tax.OEM factory replacement from honda took about eight days to from time I ordered however their site says to allow about twelve to fourteen business days.
You can go to the new member forum and introduce yourself if you like or, you can start a thread on your leak and see if our esteemed panel of experts and idiots canhelp guideyou on your way to a leak-free future.
Canuck, I agree with Yooper. Western Honda is the goodest.