Alright, I got the mercury villager fan on my fc for the past 3 years. when I wired it then it had no fuse. last week my car overheated, later I found out that the fan connector was all smoked/brittle and melted. so now I replaced the connector and added a 30amp fuse inline. all 10 ga wire. no shorts and the fuse keeps blowing. I then used an amp meter and checked the amps. when the fan initially turn on its goes up to 47amps for a split second and then it stabilizes to like 20amp. my question is should I put a bigger fuse for the fan motor or is it starting to go bad?

 

I'd say your fan motor is not right.
I've run an 2-speed 18" Lincoln fan for years now on a 30A fuse with no problems at all.

 

The inrush current you’re experiencing is normal. A circuit breaker in lieu of a fuse will alleviate tripping when the fan starts up.
Breakers have a current-time curve that allow for inrush current.

I wouldn’t fuse for 50 amps on 10 G wire or its associated connectors.

 

I sense a slow blow fuse or breaker in your future.

 

Completely read the post wrong......

 

I agree with those that said the fan motor/assembly isn't right. Given the current draw #'s the OP posted (about 20A steady state, 47A inrush) that does seem excessive. Perhaps the fan blades were damaged or otherwise out of balance as a rotating assembly, which would cause the motor to work harder and draw excessive current? When the fan runs, have you noticed its noisier than it used to be?

 

All of the above are possible, but it's used and old electric motor, so brushes are a likely contender as well.
Replacement motors are relatively cheap and easy to acquire, for something as critical as your cooling system, I'd recommend just replacing the motor and moving on.

Just for grins I checked my system again (the fan comes on so rarely, I check it to make sure it works) and noticed that I too have a 30 fuse breaker like Scathcart recommended above.
It was part of the whole Volvo setup I used and its all been so reliable, I forgot about it.

 

That's true, worn brushes would jack up the current draw too. When I did my build about 2 years ago, I went with a generic Ebay fan which is a pretty good Chinese knock-off of a SPAL 16" curved blade fan that supposedly pulls 3000 CFM of air. That fan will draw about 10~11 amps steady state, and about 20 amps inrush. I'm using a 30A fuse with it and 10 gauge wiring. No problems with it so far, it's been diligently complying with my ECU's requests to turn it on at 190*F and shut off at 183*F without fail. Using it as programmed, with a Koyo N-flow radiator, I rarely see temps > 195*F when sitting in jammed traffic on 90*F days. As long as my FC is moving, I rarely see temps over 190*F.

 

"Supposedly" being the operative word here.
Every time you see a CFM claim, unless the details of the test are given, assume it's bullshit.
A fan spinning in free air may well move 3k CFM but that is a pretend number that you'll never see in actual use. Put that fan on a radiator and make it draw through some restriction and now you're seeing what the setup is actually capable of and how that might ("might" being another operative word) work for you.
Factors like core thickness, fin density and shroud config all matter and can be varied/combined to optimize performance. The average owner has but one rad, so thickness and fin density are not easily altered, but shroud design is fairly simple to change and worth the effort.
There are standard calculations to minimize the dead spot under the fan hub that are worth knowing and using if you have some space to work with.

I am fortunate to not have to sit in traffic often and my fan never comes on if the car is moving above @ 15 MPH.
On my last major road trip (3500 miles), I'll bet the fan was on for less that ten minutes total- usually just for a minute or so leaving a gas stop.

 

Oh I did assume the "rating" was bullshit, but at less than $40 shipped, it was too good of a deal to pass up. So I made it a point to log the crap out of temps with my ECU (AEM Infinity) to characterize the fan's performance. Whatever its actual CFM is on my installation, it is enough to pull down coolant temps rather quickly (couple of minutes) after a heat soak. So even in stop & go traffic situations following a heat soak, on a 90+*F day, my fan might cycle on/off at maybe a 33% duty cycle, and never failed to keep the coolant temps below 195*F.

 

Good for you, well done.
Numbers are paper are well and good but actual performance data is all that really matters.

Except for the Washington Generals- their performance does not, and has never, mattered at all.

 

fan doesn't wobble or make noise. I will just order a new one for the sake of it..... when I looked at the wiring diagram for the villager fan, it has a 60amp fuse from Ford..... weired.