Just to add my 'two-penneth'... the CSD oil cooler is actually an air exchange cooler and not a fuel/oil exchange cooler. You're confusing the engine oil system with that of the CSD Oil Cooling System. The engine oil is cooled by fuel; or conversely, the fuel is heated by the engine oil system. Which makes more sense don't you think? If the CSD was disconnected it wouldn't then provide any heating to the fuel system!
Just a retired Flight Engineer's perspective... it would appear that you flying chaps could do with a little technical expertise up there. You see what happens when we let you loose on your own!
Happy days... now, where's my Gin & Tonic?
TCF