The fan will still draw the same amount of current regardless of the fuse rating, so long as it doesn't blow due to to high a demand a 30 will not cause problems where a 25 wouldn't.
The problem is the stupid way ford did the cooling where the fans try to get 9C lower temps, which is below that which the thermostat is trying to get it to reach, the span is way too much 3C or 4C is more normal and totally fine.
tabetha