Unless you are Turbo-Charging or Super-Charging any Gasoline Burning Engine under Racing Conditions and your Normal Oil Cooler is Clean Flowing and
NOT Clogged or leaking Oil when under use for Towing Applications ...You are --
very unlikely-- to exceed the Nominal Cold to Hot Oil Temperatures of Mobil1 5W-30 FULL Synthetic Motor Oil in a Normally Operating Automotive or Truck-SUV Engine:
PS...
If you Change from using a Normal Cast Iron Exhaust Manifold over to UN-WRAPPED - NON-CERAMIC Coated Stainless Steel Headers... Enough Radiant Heat can
--rain that energy directly into the Engine Block-- Enough to Raise the Oil Temperature via "Thermal Runaway" conditions. It is very important to understand that that Radiant Heat will --
NOT-- be affected by the Passage of Air around the Engine Block!