I did the first "hot weather" flight in my Legacy last week.  Ambient temperature at the airport was in the low nineties, although my OAT was close to 100° while taxiing out.  I believe the temperature sensor, which is on the underside of the right wingtip, was picking up heat radiating off the hot asphalt and therefore reading high.

 

Oil temperature was 161°F on takeoff.  I climbed at 160 knots and leveled off at 8,500 feet.  The oil temperature peaked at 202°F at about the time I leveled off and gradually decreased to 180°F in cruise.  CHT #2, my hottest cylinder, peaked at 385°F during the climb at about 1,260°F EGT.

 

I did not install an oil cooler door.  That's been fine so far, but I may have a problem during the winter keeping the oil warm enough.  We'll see.  I have a Performance Engines IO-550 with 8.7:1 pistons.

 

I'm offering the information as a data point in the discussion about Legacy oil temps. 

 

Dennis Johnson

Legacy N52PT