2002 road king with factory mounted oil cooler. The thermostat under the bike is leaking I want to remove it. It’s too hot down here in florida to worry if the oil flow is stopped going to the oil cooler. I accidentally unplugged both lines from the thermostat without marking them. My question is does it matter which way the oil flows through the cooler? I can’t see any markings on it , it got a chrome cover over it. Can’t find anything on line to help.

 

Nope!

 

If you have to choose.. I would connect the hot oil hose entering the top of the cooler, so colder oil comes out at the lower connection.
This way you make use of the natural flow that colder fluids settle down. Will be in theory less restrictive then the other way around.

 

^ plus air bubbles go up.

 

Gravity is your friend.