I sealed up a few engines just to do it. I wasn't having any problems but it's one less thing to have to worry about. Hardest part was waiting for the sealant to fully cure before running again. Took me about an hour to break down, seal and rebuild. Less time for the next one. I say do it if you are bored and need something to do, can't hurt. I used Racers Edge engine sealant, it didn't take a whole lot.