synthetic oil run cooler?

[travelin_farmer]

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?

[PGreenSVT]

Ynthetic oil is definitely better at handling heat than conventional oil. However when rolling down the road at 200*+ EOT you are both running 40w oils. The 5w and 15w on count when the oil is cold. when at temp they are both 40 weights.

[Fishermedic]

Being behind you his truck could have seen less cool airflow to the rad. Think drafting!

[Rick C]

Originally Posted by Fishermedic

... Think drafting!

Now THERE'S a SCARY thought...trucks drafting while towing 5th wheels...