Loud radiator fan? As soon as start

[Earthworm]

Good day all!

Wondering if anyone can please help me out. 2007 mustang gt upon start has the radiator fan sound like a jet engine. It is very loud. Any ideas? Just started yesterday.

 

[DieHarder]

Got the air conditioner on? Switch the hi-speed/low-speed relays to see if there's any change. If not, and it still makes too much noise for your liking might be time to replace it. If so, get the GT500 fan. Think of it as preventative maintenance and besides, it's a better unit.

 

[Earthworm]

Got the air conditioner on? Switch the hi-speed/low-speed relays to see if there's any change. If not, and it still makes too much noise for your liking might be time to replace it. If so, get the GT500 fan. Think of it as preventative maintenance and besides, it's a better unit.

It does it without the AC on. And with it on. Where are the relays located that you speak of?

 

[Earthworm]

Relay swap seemed to respond. Thank you!

 

[DieHarder]

Relay swap seemed to respond. Thank you!

So it's not overheating anymore? If swapping the relays made a change then you need to determine why. Was it the high-speed or low-speed?

If you want to it's easy to test a relay. Using any 12v source touch the negative lead to pin 86 and the positive lead to pin 85. If the relay clicks check for continuity with a VOM across pins 30 and 87. If you have 0 ohms it should be good. If not it's bad. Regardless, I would order another relay (cheap) and replace the one you switched out.

Here's a wiring diagram: https://iihs.net/fsm/?d=40&f=Cooling Fan.pdf

And here's a good explanation of the circuit:

 

[Earthworm]

I just switched the high with the low and vice versa. So I do not know which one is bad. I think I mis understood you on that for testing it.

When the fan was not being loud after I switched them, I heard noise from accessories, put long screw drive to alternator and sounds like that bearing is going. Ordered new one. Waiting to see if that was it. So maybe inconsistent power caused fan relay issue? Or possibly it is dragging the belt and messing with water pump?

 

[Earthworm]

So I just swapped the high and low fan relays to the horn spot and both of them made horn work. So fan issue prob not a relay issue. I am going to put the alternator in tuesday and see if that stops anything. Not sure if maybe the water pump or pump bearing?

 

[DieHarder]

If the problem remains I'd suggest it's time for another radiator fan. GET the GT500 unit. It's a direct replacement and has 7 blades vice 6.

 

[Earthworm]

Thank you for taking time to respond. I will look at that if problem remains.

 

[rocknrod]

When you get the GT500 fan you may want to look at getting this also - https://wireeverything.com/products/ols/products/2005-14-mustanggt500boss-modified-fan-resistor-pack

 

[bambam 06]

When you get the GT500 fan you may want to look at getting this also - https://wireeverything.com/products/ols/products/2005-14-mustanggt500boss-modified-fan-resistor-pack

Did you install it, how difficult was the installation with the fan in the car. Thank you.

 

[rocknrod]

In my case I replaced the entire fan to a Ford Performance 7 Blade fan along with the Fan Resistor, Easier just to replace the resistor on the car.

 

[bambam 06]

In my case I replaced the entire fan to a Ford Performance 7 Blade fan along with the Fan Resistor, Easier just to replace the resistor on the car.

I just received the new fan resistor from wireeverything, it has no info on where to attach the ground wire that comes with it. is about 30 inches long, can it be attached to any ground point or is there a specific ground point that it must be attached to? Thank you for your help.

 

[yote0]

I just received the new fan resistor from wireeverything, it has no info on where to attach the ground wire that comes with it. is about 30 inches long, can it be attached to any ground point..

Did you ever get an answer for this?

 

[DieHarder]

I would run it back to the passenger strut tower ground. That is the main ground for the battery negative. Otherwise, any point on the frame or passenger fender is fine as long as it's metal.

 

[bambam 06]

I would run it back to the passenger strut tower ground. That is the main ground for the battery negative. Otherwise, any point on the frame or passenger fender is fine as long as it's metal.

Exactly where i ran it to, Thank you.

 

[bambam 06]

Did you ever get an answer for this?

See #16 below.