KUMOOZ
Oil cooling is indeed accomplished at the Fuel Oil Heat Exchanger.
It is the cooler of preference, though there is also An Air Cooler for engine and gearbox Oil. The FOHE is bypassed at Cruise and Descent in favor of the Air Cooler.
There is no provision for Fuel Heating via the FOHE. It has been piggybacked by the AD on TRENT 700 installed on the 777. The manual I have leaves that function out of the Operator's handbook. The GE90 does include a reference to Fuel Heating in its OM. For what its worth.
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