i don't have a picture, but on my 01 s2000, when i remove the front plate on the block that houses the timing chain, there's a visible, egg shaped coolant port that requires a special o-ring because it continues into a small cavity in the timing chain plate itself. the port is on the left side, if you're looking at it from the front obviously, right next to the oil filter port. anyway, my question is wtf is this for? is it a maintenance port of some sort? and why does it continue into the timing chain plate?

 

Oil passage. Feeds the main bearings.

 

oh ok, cool. and it pokes out into the timing chain cover why exactly?

 

also, when i pulled the cover, the o-ring was pretty much eviscerated for some reason. i'm guessing that doesn't bode too well for the life of my motor, huh.

 

The timing cover just seals the end of the passage there is a threaded plug on the other end. Most likely honda left the passage open on both ends to allow cleaning of the block after machining. Replace the o-ring with a new one. They are like $3.