Minimum Engine Operating Temperatures

This Friday afternoon a friend and I road across Metro Atlanta during the first part of rush hour. From the extreme NE suburbs to the extreme W suburbs. As you might expect, it was hot, stop and go, often slow even when moving. We had fun when we got there, but it was a taxing ride for riders and bikes too -- I suspect. Which brings me to the point.

I was riding my 2004 Softail Heritage Classic, stock engine with normal Stage I upgrade and an oil cooler. My buddy was on a 2003 Kawasaki Vulcan, which is water cooled.

When we got to where we were going, his oil temperature was 180 degrees - he has a 180 degree thermostat installed, and my analog oil temperature dip stick said 220 degree. (Before I installed the oil cooler it ran 230 on a trip like that.)

My thought is that if the engine operating temperature - as reflected in the oil temperature - doesn't get up over 212 degrees for a while you won't burn off the corrosive condensation that forms as the engine cooled down last time you rode it. I have also grown up believing a cool-running engine is a healthy engine. Point is - I just flat don't know for sure and would appreciate some insights from those that do know.

I am a little concerned about the coming winter - mild in Atlanta generally - but possibly cold enough to keep oil temperature too low, possibly even with the oil cooler covered.

I'm still in a learning curve regarding these things, and would very much like to learn something from experience and wide exposure to those who know.

Thanks for any help. Good riding!

I have a 2004 Road King Classic with the 95ci stage 2 kit installed. I just went thru Death Valley California, and the ground tempeture was 122 degrees. I installed a premium Harley Davidson oil cooler prior to my trip. When I stopped in Death Valley I checked the oil tempeture and it read 234 degrees. I would suspect that the oil would have been 275 degrees without the cooler installed. The main destroyer of an air cooled Harley V-twin is heat. I would suggest to everyone to put on an oil cooler to get the most miles out of there Harley V-twin. As far as whether or not the thermostat is not letting the oil heat up enough to get read of the sludge. The oil, when it reaches 220 will boil off all the condensate and the sludge will not be far behind the condensate. I have ran synthetic in my bike since it was new and have been happy with the results. Synthetic oil will also aid in the elimination of sludge. Also, keep in mind that if you follow your owners manual and change your fluids at the intervals specified in the book, you will not build up enough sludge to worry about. And lastly, I would cover the oil cooler in the winter to make sure it doens't keep the oil to cool. Ride Safe, David.

I have a ‘99 Fatboy (EVO) with a Jagg oil cooler, the company that makes the HD coolers. With synthetic oil, the analog gage reads between 150º and 200º, down about 30º prior to the cooler. I recommend that anyone with cooler questions contact the folks at Jagg - http://www.jagg.com. They are very friendly and will answer all questions.