Easiest way would have been to disconnect each fan at the module and jump it from there. Granted there is very little free space to work, but this way you could rule in/out the fan motors as it could also be a failing fan control module. As the one fan does try to work you can rule out the fuses and the PWM relay.

Either way, you likely identified the culprit(s) and hopefully your mechanic can confirm. I just hope the mechanic doesn't overcharge you as replacing the fan motor(s) is super easy. Took me less than 1 hour. Regardless, hope you get it sorted before your road trip.

 

Yeah the limited working space was what turned me off from going through that step.

So I took it to the shop, and the tech basically told me that the car definitely wasn't overheating to any surprising level, but was definitely running hot (already known, I think). They confirmed that it was the fan assembly + the control module. They didn't actually charge me anything for the diagnostics, but they did quote me a $780 repair. The bill states that the parts cost $660 (radiator fan assembly), and they are charging $105 per hour for a little over an hour ($120 for the labor). The time estimate is probably fair but I have no clue where the $660 came from. I am looking at radiator fan assemblies right now on RockAuto, they are all sub $300. More expensive than I thought it was going to be, but definitely not $660 expensive.

This leads me to the next step, which is that I am most definitely going to do this work myself lol. However, this would technically be my first "job" I've done on any vehicle; @ILM-NC G37S , when you did yours, did you follow steps from the FSM, a video, some other resource? Or did you just fully DIY it? And if so, would you elaborate on the steps you took to take the old fan out and install the new one? Just want to make sure that before I start this project I know exactly what I am getting myself into.

EDIT: Quick side note, the "control module" is part of the radiator assembly, right? Thats the little box right in the middle of the fan? Or is this another part that could be the reason why they quoted the parts at $660?

EDIT2: Never mind, looks like the control module is a $40 piece that is the little box right on top of the fan assembly. So I have absolutely no idea where $660 came from still lol.

EDIT3: Jeez, I keep forgetting stuff. Also I asked the tech how much they'd charge me to run their own diagnostics on the engine, just to be sure that the engine is fine despite the overheating, and he basically told me the same thing you all told me, which is I should probably not worry about that as of now, and that getting diagnostics like that done would probably be a waste of money because there is no reason to believe there is anything wrong with the vehicle beyond the rad fan.

EDIT4: Okay promise last edit: do you think there would be enough of a difference between two fans to spend more on one rather than the other? Spectra Premium is $280, TYC is $115. A little sussed out from buying one that less than half the price, but RockAuto has the TYC listed as a popular item and the Spectra Premium is not, which makes me think there will probably be little to no difference.

 

New, OEM, fan motors will run $250-300 each. You might be able to shop around for a better price but they are, typically, not cheap. In my case, I was able to find a complete fan assembly from a wrecked 370z for $150 on eBay (the car was next to brand new being rear end totalled). I just checked my records and I replaced my fans 8/2017 (the donor car was 2016). Just under three (3) years later with no issues.

I don't know if you have a Coupe or sedan, but I just want to mention that Nissan parts are usually cheaper than Infiniti. Should you shop OEM.

Replacing the fan assembly is relatively easy. I used the factory manual as a guide. Technically, there are only 2 bolts (green in pic) holding the assembly in place. In my case, as I have R2C intakes, the passenger side gave me enough room to maneuver the whole assembly and remove it from the top, driver side. YMMV.

You will have to remove the whole assembly in order to gain access to the fan motor mounting bolts. Just be sure to disconnect the AT coolant lines and wiring harnesses before you remove anything. It appears daunting at first, but really it is not as bad once you get in there.

As for replacement motors, I can only advise that you shop within your budget. What matters is that they work when needed. If I can help in any way....

 

At this point in the cars life, I don't think OEM is absolutely essential. Its already out of warranty anyway, and I don't think I will see too crazy of a difference between the OEM and a good aftermarket option. In any case, I'm going to look for a fan that is well rated/reviewed and place the order. I don't really mind spending more for higher quality, I just dont want to spend more for the same exact product with a different brand name. The next update to this thread will probably be in a few days, after the fan assembly comes in and I replace it. Hopefully that will be my last update on this issue lol.

Once again, thank you for your help, and if I do end up needing any more, I'll update this thread accordingly.

EDIT: In case anyone that is reading this thread is interested, I did end up getting the Spectra Premium, the images showed it to be built closer to OEM spec, and the cheaper fan, TYC, has some reviews on Amazon saying that it is louder than the OEM fans. I'm hoping the extra $120 will pay off in terms of higher quality and quieter parts.

 

The factory fans are designed to be quiet, that's why they have a different number of blades.

Since the problem is the left fan not working, the issue is debris (leaf or twig) stopping the fan from turning, the fan motor, wire or controller.

With the car off, can you spin the fan?
Have you measured the voltage at the left fan when it is on?
• If you have 12+ volts, then the motor is bad.
• If there is no voltage (or very low) the controller is bad.

I know that you have already purchased a replacement fan, but if you can do these checks, you might be able to have a lower repair cost and return the fan.

 

Yeah the one I purchased had 9 and 11 like OEM, I'm just hoping the fan blade design/quality and the motor quality also lend themselves to quieter operation. In any case, it is a little more than just the left fan not working, the right fan is also very weak. The shop that I took it to, by some method (perhaps they have the CONSULT software that certified dealerships use, or maybe they just used their own electrical tools), concluded that the fan was not responsive, which I assume probably means that the controller is the main culprit. However, my attitude going in was that I didn't mind the cost, especially since this means I will be getting a brand new set of fans and a controller, so they should work top notch for the foreseeable future. Additionally, I am at the point where I'd prefer to get my car running properly ASAP, so the hassle of doing this check and then possibly returning my current fan, purchasing a new part, and then waiting for it to come in isn't worth the ~$150 saved (if I only needed to change one motor out or the controller).

But thank you for watching out/for the input. My fan just arrived today, unfortunately it started raining a few hours ago. I think it might be over for now so I might go out and get to work. Hopefully I can get it done before sun down. I'll update once installed.

EDIT: Gonna hold off for tomorrow, it will be easier to work with more day time and the engine would start off cooler so I don't have to wait for it to cool down to work with the radiator.

 

Okay, so the deed has been done. I just got it done today (yesterday was raining, didn't get around to it), and holy **** that took a while lol. In my defense, this was the first time I'd ever done any work on a car before, and I can't say that this was the greatest introduction. I am not gonna lie to you guys, this job took me right about 6.5 hours to get done, cleanup included. I came upon some issues with my model/year that I could not find in any videos describing how to do this DIY, and I could not find in any thread regarding this issue, or the FSMs. Primarily, this problem stemmed from the fact that the screws on the top of the radiator fan that connect the radiator fan to the fan shroud--they were not screws. And thus, I could not unscrew or screw them, and I was absolutely stumped. I ended up brute forcing them, perhaps more than I am proud of, and will now have to either JB Weld, plastic weld, or 3D print a part to make sure the radiator fan has 100% integrity (its already solid, drove 20 miles at like 90 from my parents house to my apartment, everything as it should be--this is more of looks thing as well). The radiator fan is basically "hung" off of what is essentially a rivet (you cant unscrew it, it is meant to stay embedded in the plastic). To make matters worse, the radiator fan (as you probably know), also has a set of feet. These two facts combined made it an absolute nightmare to get the fan out (this was easier) and to put the new one in (holy ****... the pain). Besides this, everything else was pretty straight forward--removing the other parts was pretty easy, and putting them back in was also pretty easy. One other hiccup I got into was that my radiator and reservoir hoses have definitely never been taken off. The smaller one (reservoir hose) was easy to figure out, just twist it and pull off at the same time. The larger one (radiator hose) was a bit more difficult bc I have large-ish hands so I couldn't easily twist that one without taking my skin off on the engine. Had to undo the other side and then use the newfound leverage to get it completely off.

All-in-all, the Auto Active Test now spins both fans up (and now the fans are spinning at a good speed, as well), however, I don't think the fans really spin up all that hard in driving/idling until 210-220F... This is hotter than my liking, so I am going to see if anyone has figured out a way to make those fans kick in sooner. I'd prefer the fans to come on easy at 200 and hard at 210. I don't want to see 220 at all.

I don't know if there would be any interest or value in this, but I was thinking I could write up a full step-by-step (with some pictures) guide from a noobs perspective, for my model and year (which I have yet to see a guide for, or alternative model/year that accurately describes every step I took). In either case, would like to thank you all again for all of your advice, it was very helpful in figuring out the steps I needed to take along the way. Now its on to actually working on performance upgrades. Starting with wheels/brakes, but still working through learning the details and what works and what doesn't.

Oh also want to note, I drained most of the coolant out of radiator to get the radiator hoses to empty out and for the reservoir to be easily removed. Should I worry about air in the system? How can I ensure that there is no air in my system/how can I get the air out?

 

Unless there was a design modification specific to the sedan, or the AWD sedan, I can't see why it was so difficult to remove the fan assembly: (2) bolts, 1 harness connector (fan module), unclip the coolant hoses (1 radiator and 2 transmission), and with some finagling the whole assembly comes out.

I have a feeling you took a unnecessary step and removed the upper radiator shroud/sight shield which is a PITA to remove. Also, you should never have had to drain the radiator and remove those hoses.

¯\_(ツ)_/¯ took me less than 1 hour start to finish though I have a Coupe. Must be a sedan thing...?

Otherwise, at least the deed is done and you seem to be good to go. As far as operating temperatures, the ECM determines what temperature the fans come on and modulates fan output. Outside from maybe getting a tune, I don't think there is any way you can change that threshold value.

Drive your car for a few days and keep a eye on the coolant level both in the overflow reservoir and radiator. As long as those levels are fine and there are no signs of running hot, you should be good to go.

Now get out and go!

 

To clarify on the bolt/rivet/whatever I was talking about--they take the place of the actual bolt highlighted in red. However, the FSM shows it as an actual threaded bolt you could easily take off. This same bolt on my vehicle was not threaded, and was embedded into the plastic (highlighted in blue) and kept in their by the wider, embedded end not being allowed to come back through the plastic. If anyone is interested, I can take pictures of what they look like on my actual vehicle. In any case, I don't believe I was looking at the wrong spot, but you could be right. At this point, I can't care too much, as you said, now its working so I am not worried. And yeah, I'm gonna be watching everything. I may take my car to my buddies place and use one of the air bleed tutorials out there on youtube or on this website just to be safe, since I don't think my radiator drain was done properly. And, by the way, the radiator flush was a tip from a DIY video I had seen, but it definitely isn't worth the hassle. Just deal with the fluid splashing out of the hoses lol.

 

From your description you did fine. Draining the coolant and removing the hoses... well, we all live and learn.

It is interesting, though. I guess replacing those two steel bolts with plastic "rivets(?)" saved Nissan a whopping 1¢.

Either way, glad it is fixed and you are up and running. Relatively speaking these are easy cars to work on. I'm in the final stages of my next mod (if the damn clockspring ever gets here). I hope you take some pride in your first DIY repair job!

 

dont know if you fixed your overheating but you have a bad or stuck thermostat. i had the same problem in my sierra pickup where I overheated sitting at lights or idle and cooled down as I drove and wind cooled the radiator.