synthetic oil run cooler?
Just returned from a camping trip with my brother in law and sister. My brother in law has a 04 and I have an 03 6.0. Both trucks are identical except he runs Motorcraft 15w - 40 oil and I run 5w - 40 Rotella T6. Driving across Kansas heat yesterday (air temp of 97) and pulling my 10k fifth wheel my EOT hit 224* and held there plus or minus 1* at highway speeds. My brothers truck right behind me was plus/minus 1* of 237* pulling his 8k fifth wheel. Coolant temps of both trucks were always within 5* of each other. That got me to thinking does full synthetic oil and lighter weight oil cool faster than conventional oil?