Ok, machfly and I tested it. Mach thanks btw.
Anyway, as HTC stated, they didn't model the rad fluid weight. I don't know why I saw different weights earlier I must have done something different.
6686 :Radiator + no drop tank mount
6796 :Radiator + drop tank mount
6796 :Radiator damaged + drop tank mount
All these tests were done with no fuel and no ammo. We did discover some strange damage issues. I believe machfly will post the video, but basically when we were trying to hit the radiator and/or the fuel, we would 'hit the pilot' even if the impact was clearly behind the pilot's seat.