I have a 2006 PM35 Stagea Autech Axis but this should apply to any VQ35 Nissan... (crosspost from M35Stagea.info)
So I was out driving the other day and got stuck in some slow traffic in a multi-story car park. I had the climate control on cold which started blowing hot air then I noticed steam coming out from under the bonnet, looked down and yep, the temperature gauge was rapidly rising! I quickly got out and checked under the bonnet and neither of my fans were working. I done all the usual things, turned the A/C off, put the heater on flat out and got out onto the open road and the temp dropped to normal straight away.
I got home and done some diagnosis, I powered up both fans and one wouldn't spin at all and one was spinning very slowly and with no real force. I gave the motors a 'tap' and the one that wasn't working fired up again but with no real urgency.
I done some googling looking for some upgraded fans and found that this issue is quite common for 350z and G35/V35 drivers, which taking into consideration that my PM35 has the same VQ35 engine that they have I thought it would be the same problem. Nissan extended the warranty on VQ35 fans for this issue (which had expired now anyway) and some people just fit new fans but some people have also had success in removing the fans and cleaning the brushes so I decided I would give that a go.
So this little write-up is based on a PM35 Stagea but as far as I'm aware, is the same for most VQ35 engined vehicles.
It's a pretty simple job and I managed it in the driveway at my unit with only basic hand-tools.
First, Remove the airbox (plastic scrivets, 1x 10mm head bolt, clamp and AFM connector) and top radiator hose. (just a squeeze clamp. You will lose a bit of coolant here but nothing too drastic)
Then 2x 10mm head screws holding the fan/fan shroud and 2x fan connectors fitted to the bottom drivers side of the shroud. (need Octopus fingers to get to these connectors from the top, it would probably be easier from underneath if you could get under there)
Next up is remove the 2x 8mm head nuts that hold the fans to the fan motors and put them aside. (they are different left to right so I marked them to go back on where they came from)
Then the 3x per motor 8mm head bolts that will get the motors out of the shroud. (light on with the photos here)
Next, which would have been much easier with a small vice, is to bend these 3x little tabs on the motor housings over, to allow the motor case to be split.
When I pulled the motors apart, two of the brushes popped out easily but two were stuck in their slides and possibly weren't contacting the Armature which would explain the poor fan performance. (note both motors had two stuck and two free brushes)
I removed the brush springs and cleaned the brushes with Emery enough to make sure they slid freely, the length of their slides.
I refitted the brush springs and locked the brushes in place with a couple of paper-clips and pieces of single core detonation wire. (you can use anything rigid and long enough to protrude from the motor housing)
I also lightly cleaned the Armature face.
Then you simply slide the two halves of the motor back together while removing your brush holders. (paper-clips and wire)
Now you fold the 3x tabs back over to keep the motor together and refit everything in reverse.
I tested the fans before refitting them to the vehicle and this job made a world of difference! The fans were actually pushing air now! They would easily be working twice as well as they were before.
Make sure when you have everything back together, you bleed the coolant correctly. (I used a funnel in the radiator and opened the bleed valve near the drivers side of the firewall and started the engine and ran the heater on hot to get the coolant circulating around)
I hope this helps someone (or saves them a lot of money) in the future as it is a relatively easy job that yields great results!
