A seal in the 4 cylinder engine around the balance shaft tends to fall out, causing a large oil leak. There is a retaining device available to prevent the seal from falling out, which can be put in place during routine timing belt maintenance.Google+
Car Problem Reports
Honda Odyssey Balance Seal Falls Out, Retaining Device Available
Honda Odyssey Problem
Engine Affected: 2.3L 4 Cylinder
Visitor, 1998 Honda Odyssey, 2.3L 4 Cylinder, 150,000 mi
Shaft seal fell out and dumped all oil in front of Target. Fortunately a passerby noticed and I stopped the engine in time. After a tow home (covered by Nationwide Insurance) and a quick pop of the timing cover, I noticed that whomever owned the car before me had a timing belt replacement but the retainer clip was not installed. If you own or buy one of these model engines, check it out before driving! This would have been a seized block if it happened on the highway.