Hey all, new guy here. Just took this beauty 2003 G35 Sedan off of my dad's hands a few months ago. She's treated me great since I got her.

That being said.. I've noticed what I perceive to be a potential problem ever since I've had it. Sometimes when driving it is ridiculously loud - like, semi-truck kind of loud. I'm pretty sure this is coming from the cooling fan. To be more specific, the sound increases as the RPM's go higher (which would make sense if it's spinning the cooling fan faster). I also kind of feel like I have less power available to me.. it just doesn't feel as spunky as it normally does.
To make things kind of irritating, it doesn't do this all the time. I'd say probably 70% of the time it does. Doesn't seem to matter whether the engine is cold or warm, or what the temperature outside is.

I know that in 2003, the cooling fans were all mechanically driven, although I'm not sure how it all works. One thing I was wondering about though, was maybe there is a faulty coolant temperature sensor that is sending a signal to turn the cooling fan on, regardless of coolant temperature.

I'm not too familiar with common problems with these vehicle yet, and my search hasn't really turned up much in terms of similar scenarios.

Anyone have any thoughts?

 

In gonna venture to say the mechanical fan clutch has failed and needs to be replaced.

With the engine off, can you turn the mechanical fan easily by hand? If it's frozen solid, replace the clutch

 

Hey,
I had actually checked that a couple weeks ago, and the fan was turnable by hand.. Wasn't crazy stiff, but also didn't continue to spin after I stopped turning it.