Put an oil temp gauge on
first.
Then you can see any changes made.
Marlin's
Marlin Corporation - First Page See our new parts has a kit for oil temp.
It replaces the air temp gauge. It can also check your head temp.
I added it to my '07 Ultra.
It was handy while riding through the desert last year. 115 degree temps.
Only thing it did was tell me the oil temp but doesn't allow for any way of cooling the oil. Once the oil gets hot, it will stay hot, even with an oil cooler.
I knew what my oil temp was but the bike ran fine. Other riders had the same oil temperature but because they didn't have a gauge, they were clue-less.
I live in Iowa and temps here get over 100 degrees but I'm not adding a cooler.
It just adds more hoses that are exposed to the chance they could be cut/ruptured and then what do you do with a leaking oil supply?
I figure if a cooler was really needed, Harley would add them as standard equipment from the factory.
Synthetic oil will help to bring the oil temp down.
Your choice on brand as everybody has an opinion.