A easy "trick" that will go almost unseen is to take some of that wide,clear packing tape and put a piece across the bottom of the cooler fins and try the car,keep adding tape to block off the airflow till you get your
oil temp where you want it.....
anything bewteen 180 and 220 is good....
on my race car with an
oil cooler, I just use duct tape on those days when the outside air temp is below about 60 degrees, pretty much anything above that, it needs no tape to keep the
oil temp in the desired range.
Cool/cold oil doesn't flow thru the engine well, and doesn't lubricate as well as hot oil.......
David