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Just bought an M35 AR-X stagea and straight off the bat the fan is shitting me to tears. It sounds like im driving a friggen EB Falcon. (Very odd that a post 2000 model petrol engine runs a viscous fan :wacko: )
I've searched the forums for an electric thermo fan solution but can't seem to find anything.
Has anyone come up with a good swap for these yet? aftermarket option or possibly a fan from a V35 skyline or something like that?

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https://www.sau.com.au/forums/topic/446905-m35-stagea-viscous-fan/
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Hey mate, yes a few people have done a swap, these fans flow more air then any thermo option out there though, so ideally you would keep it for better cooling.

That being said some guys with thick core after market radiators have made something work but I know there was lots of cutting

There is stuff about it on the forums though for sure. Search a bit more

I've run twin Davies Craig 12" thermo's in a custom made shroud, with a divider between the fans so air couldn't be pulled through from one fan to the other if their output wasn't perfectly balanced.

This was on a 52mm thick, 3 core alloy rad with at least twice the core area of the stock rad. I run a Nismo thermostat.

I ran a proper fan controller to make sure the fans reacted quickly to temp variation. I ran heavy wiring and twin 30amp relays to ensure maximum current available to both fans.

Fans were set to switch on at 88 degrees

It was shit.

On the freeway, temps would be stable until you loaded the engine, then it would spike. It would go from 80 degrees to over 90 in less than a minute and take at least 5 min of low load driving to start dropping.

In traffic; it would spike from 80ish to 90 as soon as the car was stationary and rise to 95-97 deg when you accelerated away. It would routinely run in the high 90's, and once the fans came on; they would never turn back off.

All measurements taken at 24-30 degrees.

In hotter weather the cooling system would eventually lose control of engine temperature to the point where the only option was to run the heater at Max fan set on 32 degrees.

Dropping the switch on temperature just meant the fans ran for longer; temp control didn't change at all.

When I refitted my stock fan and shoud, with no other changes; it runs between 74 and 80 ALL THE TIME.

The stock viscous fan can supply over 3200cfm of airflow at full chat; a 12" thermo is flat out at around 900cfm (regardless of what the manufacturer might "guarantee") even with 2, you are short by more than 1000cfm of airflow. You can't fit a 14 or 16" on the core due to height. SPAL fans with bigger motors will not fit.

Cut & shut AU Falcon fans might fit on a stock rad, but they wouldn't on my thick core

They just can't cope.

If you want to try; I have my full set up that you can have for the price of the fans.

  • Like 3

(Very odd that a post 2000 model petrol engine runs a viscous fan :wacko: )

I guess Nissan like them because they work. You don't want to muck around with the cooling system too much, these VQ25's are a pain to do head gaskets on. ;)

  • Like 2

I`m with you Scotty , I keep on saying to my boys , Nissan spend millions of dollars developing these bloody things and people continually go out of there way to stuff them up. Check the viscous coupling and fan for cracks , might be there ,

Edited by coparts41

Viscous couplings do fail, and as you'd know they either freewheel and do nothing; or lock solid & sound like a 747 trying to get off the ground.

Get it up to temp and test it; not that hard to do. Amayama sell OEM for around $200 and are far better than the shithouse aftermarket ones.

  • 1 year later...

Ok so.

After 18 months of putting up with the noise, enough was enough.

I've finally upgraded to a Thermo fan and ditched the old wind farm running off my water pump. (Viscous fan)

For anyone that is interested it takes about an hour an a half but the only down side is, it costs about $320 retail or about $250 trade.

If you are going to do this I highly recommend using Davies Craig parts and not cheap Chinese eBay crap.

The parts I used were a 16" Davies Craig Thermo fan kit which retails for $230 on their website and comes with all the mounting accessories needed. Part # 0066 (flows over 2000 cfm)

And the Davies Craig mechanical thermal switch combo which is $90 on their website. Part # 0400. It comes with a switch that can be adjusted from 40c up to 100c. It can be done without the thermal switch kit but with it, it makes life sooooo much easier when it comes to having the fan come on at the right time.

It can be done very annoyingly with the radiator in the car but it is 1000000% easier if you take the radiator out of the car.

If anyone needs anymore info just PM me and I'll be glad to help.

Ps it is life changing.

I hope you don't plan on driving to spirited or on too hot a day. Thermos have been proven over and over again not to work on the m35. They just can't move anywhere near enough air in comparison to the viscous fan

I run 2*12 thin thermo fan with Davies Craig digital thermo controller behind FMIC and also keep stock viscous fan running. Now when they are all running, my car is like Airbus A380 ;)

Edited by YangLIU
  • Like 2

I hope you don't plan on driving to spirited or on too hot a day. Thermos have been proven over and over again not to work on the m35. They just can't move anywhere near enough air in comparison to the viscous fan

I can't remember that exact figure but the 16 inch Davis Craig Thermo that I installed moves somewhere around 2100cfm.

I have done 7,000ks since installing and it has been through all sorts of driving conditions. I drove through the mountains near jamberoo on a 42c day and had no dramas. Not to mention a quick 6 hour trip out to condobolin in similar conditions.

I would not post a write up on the set up if I was not 100% sure it works. The key to it working is the adjustable Thermo switch set up.

If anyone on here installs the exact same set up on their car that I have and has any over heating issues afterwards, I will refund them out of my own pocket and come and reinstall the old viscous fan for them.

Provided they have no pre existing cooling issues of course.

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