Thanks ''nooby''
appreciate the input.
Though have to say, the engine oil coolers are pretty ineffective.
Still asking for someone to give me some insight on nominal MGB temp.
We had a box change on one of our 139's about 18 months ago and that one never goes above 82c, even on (heavy) climb-out with the components only permitted to cool for 30 mins between flights.
I know about the newer boxes having a small oil reservoir above each of the 90-degree input drives, but do they have a revised oil cooler system too?
Ambient temps here (UAE) range from 35 to 45c during the summer, with high RH and the atmospheric pressure as low as 993Mb during July and August.
Digressing: Once had a brand new (US-built) 139 that had it's initial compass swing during August and didn't make the second 8-point turn before both engines hit 140c, the IGB reached 110c and the #2 Hyd System was just above 120c (#1 Hyd hardly affected).