Ti550 Engine Cooling Fan [SOLVED]

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Markev

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Nissan 2012 Ti550 Pathfinder. V9X engine. 101,000km. All services completed on schedule. Now out of extended warranty.
During an air conditioner regas/check the auto electrician said the a/c was fine but the engine cooling fan wasn’t working. Apparently this causes the “high side of the a/c to get too high and as a result the air conditioner doesn’t function well.
They arrived at the conclusion that the actual engine fan was faulty because it spins freely without any resistance. They recommend taking the car to a mechanic to repair or replace the fan. Is the V9X engine fan supposed to have resistance when manually spun? I thought I read somewhere it operates differently to other engine fans.
The earliest Nissan booking i could make is ten days away for them to do an initial diagnosis. I’m wondering if there’s a fuse, sensor etc that I could check beforehand, hoping the fan is OK and there’s a simple explanation for the engine fan not to be working. Not sure if there’s fan fuses etc under the bonnet that I could check. Can’t find any relevant fuse inside the cabin near the glovebox, but not having any mechanical knowledge I don’t really know what fuse to look for.
Any advice / suggestions appreciated.
 
From memory it has been mentioned on here that the 550 runs a magnetic (I think) clutch in the fan, that is ecu controlled. I don't know if there are any fuses in the system, but Nissan can probably activate a diagnostic mode to test it. How much they would cost is anyone's guess, but may help.

The other option it to get the engine up to operating temperature and open the bonnet and see if the fan is engaged. You could also try putting the cabin blower fan on max with the air-con on and see if the engine fan engages and disengages.
 
Thanks bods. I’m confident that the engine cooling fan isn’t working: I trust the auto electrician’s assessment that it’s not engaging. He’s thinking it’s a faulty fan based on the fact that the fan is freewheeling rather than having some resistance when manually spun. I’m not sure that’s the way the Ti550’s fan is designed. I’d just like to eliminate other reasons why the fan isn’t operating eg fuse or relay switch or something similar before Nissan jump to the same conclusion. A pessimistic attitude I know but I’ve been disappointed on many occasions in the past: I’d like to be surprised and have a change of heart. Thanks for your thoughts.
 
I've checked the manual again (p74 of CO.pdf covers the V9X cooling fan assembly) and it describes examining the coupling like this:

Fan Coupling
Inspect fan coupling for oil leakage and bimetal conditions.

Now, it IS possible for this coupling to fail - mine has failed twice so far. Expecting it to happen again before the car reaches 300,000km (less than 15K km to go).

They're silicone-oil filled chambers with a bimetal strip that acts as a valve. As the bimetal heats up, it turns the valve, causing the oil to create friction between the coupling drive shaft and the fan mounting face. As it "grabs" the shaft, the fan is driven harder by the engine.

Testing yours is easy. Some people will recommend the "newspaper" method - never do this. It involves inserting a rolled-up newspaper into the fan while the engine is running. Problem with this test is that while it will indicate a faulty coupling, it can also snap or crack fan blades. Since they're pulling forward, they'll eat the radiator. There is a better and more reliable method.

With a cold engine, open the bonnet and try turning the fan. Pay attention to how much effort is required. Now warm up the car - to normal operating temperature. Pull over, turn the engine off, pop the bonnet and try turning the fan by hand (keep in mind that everything under the bonnet is quite hot). If the fan turns really easily, the coupling is shot, you need a new one. If it's firmer (than it was when cold) to turn over, it's working.
 
Thanks Old.Tony. A very comprehensive answer. I’ll give your testing procedure a go tomorrow. If the coupling is shot what gets replaced - just a coupling or a complete fan kit? Is the replacement a job for a capable independent mechanic or would Nissan need to do it?

As an aside.... the manual to which you refer CO.pdf...... is that a soft version or hard copy and if it’s the former is it available to mugs like me, simply to have a browse thru? I understand if it’s only available to people who have ‘legitimate’ reasons to consult it.

Thanks again for your response. Given your coupling has failed a few times, it looks more likely my auto electrician’s initial diagnosis is correct. If that’s the case then in many ways I’m happy because it affirms my confidence in him/his workers.
 
There's an electronic manual that floats around from time to time and a few years back I snagged it. CO.pdf is one of the files in it, I referred to it for anyone else who happened to have it.

The manuals aren't supposed to be in circulation - Nissan try to keep them in-house, but they're a valuable resource for vehicle owners and there's always someone who'll sneak something out of anywhere if they're motivated enough.

The repair job isn't a difficult one and involves unbolting the fan+coupling, removing the fan from the coupling, putting the fan on the new coupling and bolting the new coupling+fan into place. Fan belt is left alone (isn't involved in this). I removed mine without removing the shroud from the radiator - I was very careful to wiggle it out without denting the back of the radiator.
 
Went for a drive and got the temp gauge to its normal halfway level. Once stopped fan blades spun with equal resistance prior to and after the trip. Therefore assume the coupling is faulty. Guess I’ll know more in a week’s time when Nissan can find time to check it out.

After the trip and before I stopped the engine I lifted the hood and noticed the fan spinning, albeit reasonably slowly. Easily stopped it by hand. Then a manual spin had the same ‘tension’ as cold engine.
 
They're silicone-oil filled chambers with a bimetal strip that acts as a valve. As the bimetal heats up, it turns the valve, causing the oil to create friction between the coupling drive shaft and the fan mounting face. As it "grabs" the shaft, the fan is driven harder by the engine.
it doesn't grab the shaft.
typically they are a pump, like a basic torque converter. the bimetal strip turns a valve which increases the flow of silicone oil.
most common problem is the silicone oil turns to crap. clean it out and replace it.
getting the right oil is the hard bit. some aftermarket places have it, i know toyota usually does.
 
Thanks Tweak’e for your input. If Nissan determines its a faulty coupling I hope they’d offer to refil the silicone oil as an option if it’s cost effective as opposed to simply replacing the coupling/fan. I guess from a warranty perspective they’d prefer a full fan replacement. Gee.....if things didn’t go wrong I wouldn’t learn anything........perhaps I’d prefer to stay ignorant! It’s an interesting journey.
 
I'm pretty sure the fan couplings are purely electronically controlled via the bcm and ecu on our v9x models, in essence the same way an air con compressor is turned on with a magnetic clutch except this one has variable lock up points, which vary based on about 11 inputs from all around the car
 
There is definitely something different about the fan couplings. There are 3 different part numbers listed

V9x is 21082-5X20A
VQ40 is 21082-EA200
YD25 is 21082-EB30A

According to parts photos I've seen, the v9x an extra bit with an electrical connector on the rear of the viscous coupling assembly.
 
just looking at the pics of that part number, it looks like its ecu controlled.
now the catch will be is it ecu problem, actuator problem or silicone oil problem. i'm assuming its still a hydraulic type but with an actuator to control the valve.
 
V9X ENGINE COOLING SYSTEM
Electric / Viscous Cooling Fan
The engine driven Cooling Fan has a viscous
coupling & which is electrically operated via a
signal from the ECM (via the IPDM E/R). A
Fan speed sensor which sends a signal
direct to the ECM is incorporated into the hub
as well.
The Fan is mounted on a pulley which is in
turn driven by the auxiliary drive belt.
The Cooling Fan is driven separately to the
Water Pump.
NOTE:
An electrically operated cooling fan is not
fitted to V9X equipped vehicles.
 
Thanks nedm1989, bods, tweak’e & bazt.
It’s good for me to have some background information, although I’m about of my depth in understanding: but I am enjoying the challenge of learning. Hopefully the Nissan dealership will be familiar with the engine & fan. There are very few Pathfinder Ti550’s around here (we’ve seen one other), but I think there are a few Navaras with the same engine, so the dealership hopefully will be familiar with the fans operation and be able to determine what’s stopping it from working. I’ll report after next week’s appointment. Hopefully it won’t take as long for them to get the parts and find the time to do the job. We love the car and it’s great for the caravan towing. Thanks again. Great forum.
 
Nissan service dealership today confirmed the engine fan coupling is faulty. $126 charge for approx 40 minutes diagnosis. I now await availability of parts, quote and indication of when it could be done. Hopefully hear something tomorrow. Things don’t happen quickly.
 
Quote for part came today. $596 for the fan coupling. Cannot quote labour - they haven’t done one before. Coupling has to come from Noth America with a minimum of three weeks. Tried A couple of automotive shops for other options but apparently there are no ‘after market’ couplings available. Looks like a month before we’re fixed. Would this be a ‘normal’ Experience?
 
Not in the least.

Have a look at this page. That's the last fan I bought and it's still going strong. Price is pretty good too. Service was outstanding. I strongly recommend giving them a call in the morning and see if they can help with the V9X.

The alternative is to head to your local Toymotor dealership and buy some Viscous Fan Hub Silicone Oil. Here's a link showing what I mean. Remove yours, open it, pour some of this in, close it back up and reinstall.
 
Thanks ‘Old.Tony’ for your thoughts. I admire your mechanical skills and knowledge. I have none!
I rang the next nearest Nissan dealership 200km down the road. Spoke to parts department. After giving him the VIN no. he said the part was available overnight from Melbourne. He put me thru to service. They weren’t keen to order part until they’d made a diagnosis. Drove down the next day and they confirmed the original diagnosis and ordered the part. It arrived the next morning and they had it fitted the next afternoon. Total cost $830. The coupling was $70 cheaper than original quote. Labour was expensive I guess but I was grateful for their prompt service. They left me with a wad of paperwork: methodology of component function test, diagrams, ECS wiring diagrams - all with handwritten notes of voltages, readings etc.
Overall: disappointed with my local dealership; pleased with the response and accuracy of the next dealership and that the engine fan (& hence aircon) is working again. Hope there’s no more major failures within the car. How come it happens six months after the extended warranty expired!!!!!!!!
 
My first failure of this component happened during warranty (lucky eh?). My dealer first blamed the radiator itself and sent me to a radiator specialist who took 30 seconds to point back to the fan and back in the direction of the dealer.

The sad part is that although our dealers are supposed to know our cars very, very well, the truth is that the people hired by dealers get their job and have to follow a specific set of instructions written by the manufacturer for fault diagnostics. Common sense is unfortunately not always involved, and it may take some time for the dealer mechanic to become aware enough of what common issues each model of car has before they can be more reliable - and by that time, they get a better paid job at a private mechanical workshop.

Glad to hear yours is fixed, though. Bit pricey but at least the job is done!
 

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