Coolant orings

[CISE]

I am replacing orings on the coolant pipes on top of the engine. The original orings are flat across the top, but the new ones have a raised ridge on one end of the oring.

Does the high ridge go in first or does it go in last?

Thanks

[Chrisj CMA]

I recently changed out some of these (friends bike) and put them in so the low end of the o-ring went in first followed by the raised part.......they arent leaking

[CISE]

Thanks... getting tired of not riding 

[deadwood]

FWIW
Replace mine this weekend.
When I removed the cooling tubes I put the ends with the o-rings under a 10X magnifier and compared them to the new o-rings. I was able to determine they go in with the larger diameter towards the tube and the smaller diameter toward the engine.