Viscous Fan Hub

Submitted: Tuesday, Feb 14, 2006 at 23:30

The Boy

Hi All,
would someone be able to tell me how many ml's of silicone fluid is required for an overhaul on a GU 4.2 viscous fan hub.
Have done Toyota's ones before but not Nissans and my dealer is unable/unwilling to tell me.
Have a Gregory's manual for my bus but is next to useless for any real info

Thank you
The Boy
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AnswerID: 155053   Submitted: Tuesday, Feb 14, 2006 at 23:53

Billowaggi replied:

My advice would be if you think that the fan clutch is not working to raplace it. If it is low on fluid it most probably has a leak and topping up will just prolong the inevitable. I am fairly shure that the Nissan unit is sealed and cannot be topped up. Apart from the amount of fluid in the unit other things can go wrong, I have seen near new clutches that will not engage but are not low on fluid.
Regards Ken.
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AnswerID: 155059   Submitted: Wednesday, Feb 15, 2006 at 00:13

Member - Ed. C. replied:

G'day Laddie,
When I did mine a coupla yrs ago (I had 'suspected' that it _may_ not have been working as efficiently as it should), I used 1x 18ml tube (Toyota part# 08816-10001 , less than 10 bucks at the time).....
'Yota parts bloke said "ya might need 1, or ya might need 2", so I bought 2, used 1 & it's working just fine & I haven't touched it since:-))

I didn't clean out or remove any of the existing stuff, just added the 18ml & put it back together, & like I said, it's working just fine..... (YMMV)

Regards,
Ed. C.

Confucius say.....
"He who lie underneath automobile with tool in hand,
....Not necessarily mechanic!!"
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AnswerID: 155088   Submitted: Wednesday, Feb 15, 2006 at 08:04

4145derek replied:

Hi Boy

I have been re-filling these fan hubs for years and that includes the sealed ones that required 2 holes drilled and then pressure filled and sealed again with snap off blanking screws.

1 bottle of Toyota silicone oil will do the job but make sure to wobble the hub before removing it from the vehicle. If there is play in the hub replace it. While there check for signs of play or weepage on the waterpump shaft and replace it while you are busy.

Regards Derek
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AnswerID: 155107   Submitted: Wednesday, Feb 15, 2006 at 09:51

Billowaggi replied:

I think you will find that if you put enough fluid in they will always drive, but will not idle when cold, you might as well fit a solid drive fan.
Regards Ken.
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Reply 4 of 8
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AnswerID: 155125   Submitted: Wednesday, Feb 15, 2006 at 12:17

Flash replied:

Yeh,
trial and error on my Patrol. Too much fluid and they will not cut out at all- when I first did mine I added too much, but after about three removal/ disassembly exercises removing some fluid each time it now works a treat.
Cheers
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FollowupID: 409088   Submitted: Wednesday, Feb 15, 2006 at 13:44

Member - Roachie (SA) posted:

Flash,

Did you find that the large, thin, rubber "O" ring stretched/expanded so much that it couldn't be re-fitted? This happened on mine, but it may have been because I let it dry out.

I'd actually bought a new viscous hub first and fitted it. I'd kept the old one and decided to pull it apart to see what was inside. Some days/weeks later, when I went to re-assemble it, the rubber "band" was about 1" too long to fit back into the groove provided. I ended up chucking the whole lot in the bin.

Cheers

Roachie
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FollowupID: 409119   Submitted: Wednesday, Feb 15, 2006 at 17:27

Flash posted:

The rubber stretched a bit, but no so much I couldn't "push" it into the slot during assembly.
Another thing that would probably work is what I have to do with my pool filter O-ring.... That is leave it in the freezer a while before re-assembly.
Cheers
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AnswerID: 155154   Submitted: Wednesday, Feb 15, 2006 at 15:04

The Boy replied:

Thanks All for your replies, I have been doing some searching through the archives of this site on issues of running hot Patrols. many Thanks to people like Roachie for posting his finding and replacement items on his Patrol to try and cure this problem. Although after reading whats on Roachie vehicle "gadgets and gizmos" I think he needed to upgrade the turbo just to carry the extra weight....lol.
Bought the Patrol new in 01 and has always run hot under load "towing Camper Trailer" so I have learnt to drive using the water temp gauge. (VDO Gauge on dash)

After searching through the archives for some time and many posts I see that this problem has not been resolved yet, Im not interested in getting the old girl to run at 80deg under any load but I am interested to see if I can bring the temp down by 5 to 10 deg if possible. I guess I would like to strike a balance between the temp and the budget, make the changes but be cost effective.

I have fitted a new 3" exhaust and dump pipe to the bus and was amazed by the increase in the bottom end, from the 1000 to 1500 rpm range is a hell of a lot better. Will be looking at the turbo upgrade as soon a the budget can spare it hence my reason why I would like to knock the edge of the temp a little.

Have heard that the new Patrols run a higher pressure radiator cap in an attempt to cure this problem but from what I have seen on the net the new Patrol still run hot. I recall Holden did the same thing on the Commodores but did not upgrade the water heater inside the car, some major leaks occured inside the commodores. Hope nissan didnt make the same mistake haha

Thanks again all

The Boy
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Reply 6 of 8
FollowupID: 409138   Submitted: Wednesday, Feb 15, 2006 at 18:34

Flash posted:

My Turboed GQ runs cool all the time.
A few pointers which may help....
1.Obviously the Viscous fan is critical. If it is not working 100% when you need it you'll overheat.

2.Use the lowest % glycol Vs water mix you can get away with considering your winter temperatures. Water is a better coolant than glycol because it needs more kilojoules (or BTU's or what ever you prefer) to raise a litre of water by 1 degree than the glycol. I run only about 10% glycol. If you can get away with no glycol then do so - but of course you need a suitable corrosion preventative. I use Redline's "Water wetter" additive which I believe helped considerably. See their website.
http://www.redlineoil.com/products_coolant.asp?productID=53<a

3. Radiator must obviously be clean internally as well as externally.

4. I tapped in to the heater line using a commodore heater valve, and added an extra mini radiator (using a heater core from the wreckers) fitted in my 'roo-bar, so that I always have water flowing thru the heater line instead of it being shut off when you are not using the heater.

5. I have an oil cooler fitted- figured it takes load of the internal heat exchange cooler near the oil filters.

6.Finally, I fitted a High flow thermostat, though I don't know how that compares with the genuine Nissan variety as mine went in the bin years ago.
Net result is an engine which NEVER runs hot even though I tow a heavy van and boat and run 12psi boost on my turbo.
Cheers
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AnswerID: 155157   Submitted: Wednesday, Feb 15, 2006 at 15:11

Gossy replied:

I had heating problems on my GQ the other week with the heatwave in Adelaide bringing out the problem.
NATRAD fixed the problem fine and they said that they put "two tubes" of lube in (sorry but I don't know how much that was). Running much cooler now!
Sorry it doesn't really answer your question but for the sake of a couple of hundred dollars (or less as I had a flush and fluid change as well) it could be worth just giving the car to a radiator place to do.

Cheers,
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Reply 7 of 8
AnswerID: 155421   Submitted: Thursday, Feb 16, 2006 at 19:14

DesC replied:

I put 18 mls in my GU 4.2D before christmas, should have only put 10 mls as fan runs too hard too often. Also fitted latest radiator cutout switch for the Aircon clutch and that stopped cutting the A/C out so early. Uses a bit more fuel with the 18mls but on long hills with big trailer in western qld at speed limit it doesn't get warm now, only when you are ringing its neck in 3rd going up the Canarvons and ranges like that when over 40c.
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