On my way home yesterday, a 250 mile trip, my engine ran hot about 4-5 times. I have a DD 60S engine and have dash air. One time the DDEC flashed and the temperature was at 217 degrees. I ran the dash air conditioning so the fan would run more and it seemed to help. I would sometimes run 50-60 miles at the normal temperature, then the gauge would start to rise quickly and stay there for maybe 30 seconds and then quickly back to normal. I know I need to get it into the shop but I live about 250 miles from Nashville. Any ideas as to what is causing this and how to maybe get it to the shop without it running hot?