Tried to google this for ages but can't find anything.

How much power, voltage/amp does the radiator fan engine need/want? .. right now it's on 15amp but im afraid it's not enough?

 

Factory fan, or aftermarket? Most of the aftermarket single fans draw anywhere in the 7~14 amp range, depending on the heavy duty rating of the motor. I would think you're fine at 15 amps. A good way to tell is by what your fuse is doing. If you're not overloading and blowing a 15 amp fuse, you're cool.

 

Well it's my dads car and we just bought it, -86 305 v8.
The thing is that the temp sensor or a relay was broken so the fan never started, so we connected it to the battery (I told them not to...) to se if the fan engine worked, it ended with smokes and im sure something more happend somewhere becouse now we can't get any power at all from the fan cable.

Anyway we bought some new stuffs and connected a new temp sensor to the cooling system, first we took power from the lights which ended in a disco when the fan kicked in.
then we took power from some red cable coming from a relay we had no idea where it was for, we had a 15amp fuse and it blowed, replaced with a 20amp and now it works.

The fan engine is brand new and should be just like the original one, I don't want him to overload it like the old one, I guess right now it's not over 20amp, To much for the engine? spins pretty fast tho.