I bought my 16 yr old a 2003 G35 Sedan a few weeks ago and have an issue with it running hot. Someone suggested testing the fan clutch, telling me to attempt to spin when cold, it will rotate 1 or so blades. Once hot, it should have a lot of resistance. I tested it and once hot, the fan spun freely so I replaced the clutch fan.

I also bought a Lisle Funnel and did the procedure to rid the cooling system of any trapped air. I had about 4 small bubbles come up after about 4-5 minutes and 2 larger bubbles a minute or so later. (Coolant flush was performed 3,000 miles ago)

We drove the car tonight for about an hour, 72 degrees, no A/C running (it blows ice cold btw) with the temp gauge pinned at about halfway. After about 50 minutes into the drive, sitting at a red light, the needle started to climb towards the H, 1 line below the last one. As soon as we started moving again, it dropped back down to a couple ticks above halfway and stayed there for the last 10 minutes of the drive.

I attempted to spin the fan it and it spun freely! Could it be I got a defective fan clutch?
I checked top and bottom hoses off the radiator and both are hot. What else could it be?
Thermostat? Temp sending unit?

Any help is appreciated!

Other than this issue the car runs perfectly! Just replaced rotors and pads on all corners and a right rear wheel bearing. Oil/filter change, new wiper blades, buffed it out and cleaned the leather. It is hard to believe it is a 2003, it is in incredible condition. Everything else works as new.
Thanks in advance for any insight.

 

Are both fans on when the a/c is on? Could also be a partially plugged radiator or still air in the system. Generally when temps climb when stopped it is a lack of air flow through the radiator which is usually the fan(s) or a clogged radiator.

 

I have a pulley driven fan and one electric fan. I cranked the A/C when I had the Linsle funnel in place and let it run until I saw the electric fan cycle on and off. It is exhibiting the same issue I had before replacing the fan clutch,

Does it make sense at all that the fan spins easily after the car warms up to temp? Could it be that I got a bad replacement fan clutch? I appreciate the reply

 

It is possible the fan clutch is bad.

 

The part you replaced looks like this right? Aluminum heatsink with the coil spring wound up on the back.

http://www.partsgeek.com/kc999z2-infiniti-g35-fan-clutch.html?utm_source=shopzilla&utm_medium=pf&utm _content=hcs&utm_campaign=PartsGeek+ShopZilla&fp=p p&utm_term=Infiniti+Fan+Clutch

 

Amazing Cleric, yes, not only does it look like that, it is the actual brand I bought.
I beleive you were the kind soul that directed me to a faulty fan clutch to begin with. What are the chances I got a defective one?
It spins freely once the engine is at operating temperature.

 

I think we need someone who owns one to chime in with how THEIRS operates, I have never seen a clutch style fan that would spin freely when hot (unless it was broken) but I can't say 100% that this isn't the case for this vehicle. Some madman engineer might have master plan that makes his fan different than literally every other clutch fan in the world.

I still think it's the problem though since the overheat condition does away when you start moving and air is pushing through the radiator again.

The electric fan can't be installed backwards can it?

 

That would be great if someone that does not have an overheating issue could check their clutch fan and let me know, great idea. I remember you telling me that if it spins freely once hot, it is bad. I "googled" it and that seems to be the correct diagnosis.

The only other issue that I researched that could cause this is air in the system and I "burped it" with the spillproof funnel. I let the car run for 15 minutes and saw a total of 6 bubbles come up.

The electric fan in front of the radiator (I only have 1, driver side) cycles on and off with the A/C running, usually for about 30 seconds. Using the funnel, I let it run in the driveway for 15 minutes with the AC cranked down to 60 degrees and the temp gauge never went past halfway. I cannot see by looking at it how it could be installed backwards

The only other things I could think of is the radiator fins are clogged with debris, keeping air from flowing through while stopped. I cannot see anything by looking at it though. Both top and bottom hoses are hot. The cap makes a good seal and I have no leaks anywhere. The resivor tank is right at the max line.

The larger belt on the pulley looks to be in good condition, the smaller one has some small cracks in it. I thought maybe the belt is worn and slipping but I would think I would get some squealing noise if that was the case.

After installing the new fan clutch, right on startup until I get about 50 yards down the road, you can really hear the fan and then it fades away. Almost describe it as a jet taking off sound. I did not hear that before replacing it.

Thanks for your input Cleric as always