R34 Radiator fan issue

[Bllack]

Hey all, The fan on my 34 is pulling and over excessive amount of air, it doesn’t cause any heating issues or anything of that, it’s just so loud and is getting annoying hearing it constantly.

problem started months ago when my shroud hit the fan and pretty much exploded the shroud, from then on ive been able to hear the air coming of it and it’s louder then the exhaust 

new shroud has been put in, Any ideas and what to look for for a possible fix? Thanks

[GTSBoy]

You've f**ked the viscous clutch on it.  New one required.

[Bllack]

Gtsboy 

16 minutes ago, GTSBoy said:

You've f**ked the viscous clutch on it.  New one required.

Thanks heap mate, I will look into it! Much appreciated 

Edited August 12, 2018 by Bllack

[niZmO_Man]

With the engine off, spin the fan, it should have resistance but still rotate.

[GTSBoy]

18 minutes ago, niZmO_Man said:

With the engine off, spin the fan, it should have resistance but still rotate.

Sadly, it's not quite a good enough test.  They can still do what you say, and be f**ked enough to not slip enough when they should and make you sound like you're driving a Patrol.

A warning.  Do NOT but a Davies Craig clutch hub, or a no-name unit off eBay.  They are all shit.  They will sound like they're stuffed already. I think Dayco might be OK, and they seem to be available on eBay.  Genuine Nissan is the best choice.  Do not allow someone to sell you one for a 4WD or anything other than the right one, because they have different temperature actuation points and resistance, depending on the application, fan used, etc etc.

[Kinkstaah]

I bought one recently (and have for sale, they are fairly expensive).
 

Smashing the fan into something and then causing sound is a problem. You can usually see the fan not spinning straight on the hub if its fked. If its louder than the exhaust genuinely (and absolutely ISNT hitting anything.....) then yes replace it ASAP.

[V28VX37]

Another thing to do whilst you're at it, check that your water pump bearing is ok and rotates level. Your clutch fan is hanging off it and if it's not level it'll make the fan blade wobble and explode before long. Fairly easy to the check: Record a slo-mo clip from directly above using your smartphone with the engine running and play back; if it's wobbling at the base you might be up for a new water pump too...

[89CAL]

Dayco ones are fine. I run an RB30 Dayco fan hub in mine as I needed a little extra clearance between the engine and radiator. Seems to behave like an OEM hub

Davies Craig are terrible. May as well just weld the fan to the water pump

[niZmO_Man]

22 hours ago, GTSBoy said:

Sadly, it's not quite a good enough test.  They can still do what you say, and be f**ked enough to not slip enough when they should and make you sound like you're driving a Patrol.

A warning.  Do NOT but a Davies Craig clutch hub, or a no-name unit off eBay.  They are all shit.  They will sound like they're stuffed already. I think Dayco might be OK, and they seem to be available on eBay.  Genuine Nissan is the best choice.  Do not allow someone to sell you one for a 4WD or anything other than the right one, because they have different temperature actuation points and resistance, depending on the application, fan used, etc etc.

Yeah but it's a quick way to check if the hub locked (they can also free spin).

Oh and back in the R31 days, we used "sounds like an XF Falcon"

[Kapr]

Hi,

I do not want to start a new thread cuz there is already a tone of info about clutch fan so i ask here.

My car(R34 with RB20DE NEO and new radiator) starts to sound like jet/taxi/old Nissan Patrol when i leaving from anywhere.
Even when iam reversing the fan goes with the RPMs
It is kinda hot right now(32+ Celsius) but i do not think it should do that(AC is off).

I fly thru comments about that and it seems i maybe have seized clutch fan?
What the clutch fan should do if it is not broken?

When the car is cold after the start...should the fan goes with the RPMS or not?
If i try to spin the fan with engine off(cold) should there be any resistance( guessing that if it is really seized that would be "harder" to spin?)

Car is not overheating or anything like that.

And last...if it is broken and i need a new one i found this: https://www.ebay.com/itm/224430896805?epid=9029172050&hash=item34411fb6a5:g:-F8AAOSwgrNgfPsU
Is it good? It should be for my engine too.

Thank you very much for help! :-) 

[GTSBoy]

On 7/20/2022 at 6:00 PM, Kapr said:

When the car is cold after the start

Fan should be quiet at that time. The clutch should only start to "lock up" as it gets hot.

On 7/20/2022 at 6:00 PM, Kapr said:

If i try to spin the fan with engine off(cold) should there be any resistance

Some but not much. If it is quite stiff, then it's well f**ked.

On 7/20/2022 at 6:00 PM, Kapr said:

guessing that if it is really seized that would be "harder" to spin?)

Yup.

On 7/20/2022 at 6:00 PM, Kapr said:

and i need a new one i found this: https://www.ebay.com/itm/224430896805?epid=9029172050&hash=item34411fb6a5:g:-F8AAOSwgrNgfPsU

As per my post above....I think Dayco might be OK. Not 100% sure. I've not had any luck at all with anything aftermarket. Only the genuine original Nissan one.

[Kapr]

Hi...many thanks for the reply.
Iam going to test the clutch fan today and see if it is really locked/bad.

When i start the car the fan is quiet...but from what i read...when i step on the gas as it is cold...fan should not start to spin with RPMs just yet or?

Yeah i look up the original and it costs 500USD just a part alone(no postage VAT etc...)

That Dayco one is 220 USD with postage.

So DK if i should spend more than double and be 100% positive that is going to work or "cheap" out and get that Dayco one.

 

[Kapr]

So i test the clutch fan.

When i first started the car i let the rpms settle down and then just unparked from my place(cold garage place)

I try to rev it couple of times and fan was rather quite.

Then i drive like 500m and parked. Car was already at the temp and fan start to move faster with rpm since that.

But it is rather hot here(33+ Celsius) and city driving.

Could this be normal cuz it hot?

This video is when i came to the car(cold...not driven for a day)

 

[GTSBoy]

On 7/20/2022 at 11:09 PM, Kapr said:

when i step on the gas as it is cold...fan should not start to spin with RPMs just yet or?

Fan should spin. But because the viscous fluid in the coupling should be "thin" until it heats up, it won't transmit as much drive to the fan as it can once hot. So the fan runs much slower cold than hot.

 

On 7/21/2022 at 3:16 AM, Kapr said:

But it is rather hot here(33+ Celsius) and city driving.

33°C is a pleasant spring day here in Australia. It shouldn't be roaring. It should definitely be louder and working harder, but shouldn't sound like a crappy old 4WD.

 

Just to be clear...... when these things fail they don't necessarily fail totally. They don't necessarily just lock on cold. They can still be quiet when cold, but just get noisy at lower temperatures than they are supposed to.

 

I bought genuine Nissan. I gave up on the aftermarket ones.

[Kapr]

Thanks.
For now i just dont know. I know 100% that when car was broken and only 5cyl works(but it was much cooler) i heard that fan only on the start and after that...nothing.
Right just a couple of minutes after the start...whenever i accelerate or even on place when i "step" on it...the fan spins with the rpms and it sounds like old Patrol or some 4WD...like every time.
It happens when i go downill and downshift the fan goes with the rpm too...

So maybe it is broken?

Yeah i rather buy Nissan one even if it expensive 🙂 

Edited July 21, 2022 by Kapr

[TXSquirrel]

If you dig deeper, you can find interchangeable Nissan OEM fan clutch from other models.  Those will be much cheaper and still available from any local Nissan dealer.  I have not looked into R34, but I know the older Nissan Pathfinder/Xterra/Frontier fan clutch fits R32 perfectly and runs about ~$170 USD.

[GTSBoy]

They don't all have the same temperature setpoint though. Very hard to know what that is too.

[TXSquirrel]

Yeah but how different can it be, maybe 100°C vs 105°C?  This is a viscous fan we're talking about, I mean how accurate can that be to begin with?  

[joshuaho96]

On 7/21/2022 at 6:23 AM, GTSBoy said:

They don't all have the same temperature setpoint though. Very hard to know what that is too.

From what I see the difference isn't so much the temperature setpoint which is controlled by the bimetallic strip material but rather the engagement profile. Interestingly enough this pdf suggests that if they are dimensionally near identical then they should behave comparably: https://www.4s.com/media/3747/4s410-fan-clutches-standard-heavy-severe.pdf

The danger supposedly is that if you have too much engagement from a "heavy duty" fan clutch then the fan could spin far too quickly and disassemble itself.

[GTSBoy]

On 7/22/2022 at 9:35 AM, joshuaho96 said:

emperature setpoint which is controlled by the bimetallic strip material but rather the engagement profile

Yeah, nah. It's the viscosity of the silicone fill fluid. It is available in....many different gooeynesses.

You can't split the Nissan ones, but you can split the Toyota ones and there have been numerous successful reports of refilling them with different silicone oils and different quantities - learning the parameters that control how they operate.