I remember that Airbus heats its fuel in the tank by pumping too much fuel to the engines, thus pressing the excessive warm fuel back into the outer tank where it warms up the remaining fuel there.
But it is a small amount of fuel and the effect is limited. I meet A319 that have flown over 6 hours, the fuel tank temp now is around M18degC.
but on the Boeing hot engine oil is passed, via lines, through cold fuel thus warming the fuel and cooling the oil.
I hope you are talking about in the engine. Engine oil does not leave the engine.