Just got a 03 636 a few weeks ago. I've put about a thousand miles on it since i got it. The day I got home on it for the first time a smelled antifreeze(everyone knows what warm antifreeze smells like) I didn't think much about it cause I've never owned a 4 cylinder bike till this one, I traded an 07 ninja ex250 for it, anyway i got to looking at the bike to see if i could maybe see where it was coming from and on the left side of the motor almost under the bike there is a housing, Looks kinda like a thermostat housing on a car where the radiator hose goes in, It's got a slight drip.... maybe 1 drip every 2 mins or so. i can't tell if it's coming from around the housing or maybe it's the hose clamp that holds the hose on. But when i took the radiator cap off to check the antifreeze it was at the top of the filler neck! I know it is leaking and I need to fix right away.Anyone have that problem? I guess I just need to take it to the local shop and have it checked out

 

Welcome to the forum. That is the waterpump housing. Check the tightness of the bolts and the hose clamp. There is a drain bolt right in the center of the waterpump just above the hose that could be loose. There was a service bulletin on the 03 636's for loose hose clamps.