patrol tb42 e fan clutch runnimg very often

[huardlc]

hi guys.
the viscous fan behind my radiator on my gq tb42e is running very often. replaced the fan clutch but still the same. tried with no thermostat to keep water cooler but still the same. its been minus 1 degrees lately and the fan is still running...
i start to think that the fan itself is out of wack...
would you have any ideas guys about this annoying problem. and the temp guage on dash is fine...
thanks for your time larry

[Bloodyaussie]

The viscous is stuffed mate........ you need to replace it... easy job!

[huardlc]

its brand new so the problem is not from the viscous..something else makes it running or the fan is out of balance..thats my problem..seems easy but its not ha ha ha thanks anyway

[Mick Patroln]

Hi Huardlc mate I've got or had the same problem both my clutch fan and fan were brand new and it was only after months and months it slowly started to get better and turn off and on! Even now my clutch fan will sometimes come on and stay on and yet my temp sits almost on the bottom cold line. As time goes on though it seems to be getting better and working when it needs too and turning off when its not needed. possibly just needs time to ( or long time too haha) wear in?

[huardlc]

hi mick thanks. yes mine is running very often but comes off is the engine is running on high revs, like is disengaging due t excessive speed. i read that it could be a blockage in the radiator.that would generate too much heat on the head of the fan clutch.the only problem is that it is doing it when the temp sits on cold, like you bottom mark. was just looking on e bay and noticed that the fan blades ona fan are not positionned equally around the hub, but more like 4 onone part and 3 on the other part of the fan..balancing thing ?

[Mick Patroln]

yeh right I couldn't tell you for sure mate but if your fan wasn't balanced right you would definatly know about it as the fan wouldn't spin straight so to speak! it would wobble like mad! your problem sounds identical to mine so if you can put up with it for a while and see how it goes it may wear in and come good like mine has.

[huardlc]

yes possible mick i know that its the air flow that goes on the head of the clutch and the little metal strip that makes the thing engaging or not....

[Bloodyaussie]

Where is the viscous from... is it genuine Nissan?

[Col.T]

G'day Larry,
really, really dumb question.
What starts/triggers the fan? Is it a thermostat/sensor of some kind? If so could it be that that is cactus?
If it automatically runs when the radiator cap thermostat opens (which sounds reasonable for a 'viscous' unit) then maybe that's operating at the wrong temp..
As I say a bit dumb but what the....
Col.

[Bloodyaussie]

Viscous fans work by oil heating up in the fan a locking the fan so it spins at the same rpm as the engine and when it cools the fan is allowed to spin more freely .... well sort of anyway..

[MudRunnerTD]

G'day Larry,
really, really dumb question.
What starts/triggers the fan? Is it a thermostat/sensor of some kind? If so could it be that that is cactus?
If it automatically runs when the radiator cap thermostat opens (which sounds reasonable for a 'viscous' unit) then maybe that's operating at the wrong temp..
As I say a bit dumb but what the....
Col.


Not a dumb question at all mate but the answer is that the viscous fan has a heat sensitive spring in the centre of it, when the spring heats to a set temp it expands and compresses the fan hub and it engages.

The fan will spin all the time but without load, when it engages you can hear it load up and spin harder until the engine cools below the trigger point then it lets to as the fan spins without load again.

[Col.T]

Thanks Daz.
on that basis it looks as if the fan itself is cactus 'cause if it was O.K. it wouldn't engage when the motor's cold.
What else could it be?????
Col.

[Bloodyaussie]

Those fans always engage at first when cold and as you drive off they disengage.

They can stuff up either way.. I have had them lock on and its like driving a truck and I have had one that would not come on at all...

[Dales300exc]

A mate had 3 dud viscous hubs they were brand new. Either try another or buy genuine.

[huardlc]

yes thats right. and no Col, its not a stupid question. if we all knew everything, we will probably be doing something else...bloody is right. its the oil inside the fan(clutch) that makes contact and locking it up.i think the heat is transmitted via the little strip of metal in front of the clutch itself.
the problem i hve is that it starts even with very cold engine. and yes bloody, i dont think its genuine nissan.