I did a search on the Forum for Optimum Oil Temps and I found a survey that but didn't find anything specific or technical. I installed a MoCo Oil Cooler before I added the LCD Oil Temp Gauge so I don't unfortunately have any comparisons. I run HD 20-50 Synthetic in the motor and a couple of runs out 60 miles and back on a 60 degree day at 65 mph average netted 215 to 220 degrees whereas a 5 mile mile trip at 45mph on a 60 degree day showed 161 degrees at which the Oil Cooler would not even be circulating....I don't plan to get hung up on oil temps on my 2009 FXDC but I am curious if any of the many knowledgeable guys or gals have any comparative facts and figures...

GARY