Td5 viscous fan clutch

[feraldisco]

Hi - my fan clutch can't be spun by hand more than a quarter of a turn with the engine off and cold - it's not seized but there's a fair bit of resistance there even when cold such that the fan starts spinning as soon as the motor is turned on and the fan can't be slowed by dragging a bit of cardboard against the blades...which I assume is ok when hot but not when cold. I assume it needs replacing?

[AK83]

Up your way, I'd say replace(going from your post).

I had a similar issue with my RRC way back, viscous was a constant source of pain, but one of those units did the same as yours, locked itself full time(so to speak).
Worse is when it doesn't lock tho.

Your only concern would be possibly not warming up as quickly as it should .. with the coming winter now and up in the ACT .. would be a concern
Fuel consumption would be a wee bit higher too.

But before you condemn it, can you hear it whilst driving say at 80 or 100 or so, in a lower gear, say 3K rpm?
If it's really locked up, it'd make a loud fan whooshy noise all the time, never stopping.

From cold, it will usually make an initial loud fan noise maybe 20-30sec or so after first cold start, then quieten down as it unlocks itself due to the cold.
That(to me) is a normal viscous fan operation .. for most vehicles.
My RRC did, my Rodeo did, my Frontera did, Falcon .. basically every recent car I've had in the past 15 or so years, other than this current Tdi D1 I have! Fan hardly makes any noise.

Note that if you do a cardboard test, it has to be a very strong cardboard test .. not just allow a bit of cardboard to flap against the fan blades!
Make sure you have a nice strong rolled up newspaper type cardboard stopper!
Another test for dragging is, with the help of someone to start the engine, hold the rolled up against a blade, and get someone to start the engine up.
It feels a bit strange at first as your initial instinct is that you're going to get whacked or something.
Doing the test with the cardboard is actually more dangerous, firstly in that if there's a fracture in any blade(not impossible), then jamming a thing into those moving blades could weaken it to the point where it breaks off and .. does damage in a random chaotic manner!
(I've had a metal blade snap off a cooling fan .. so don't under estimate them)
Doing the test from a standing start is a bit safer in that respect ... except if your viscous is locked up and the rolled up cardboard can't hold the fan back and it flicks it up/out/wherever.

[PhilipA]

The fluid pools in the bottom of the VC when it is stopped and it is more viscous when cold. So it is stiff.

It is VERY unusual for a VC to seize up and in almost all cases failure is due to the fluid leaking out of the shaft seal.

The two failures that can make it seize are
1 a screw through the housing.
2 the spring on the front being adjusted up. I don't think a broken spring could seize it.

In other words look for a screw, and if no screw don't worry be happy.

Regards Philip A

[John_D4]

So I’m still learning...should u be able to turn the fan freely with the engine off and cold? I don’t think mine does that by memory. I think it runs all the time.

[AK83]

I do the screw thing into the body, when stuck with a dead VC and no other option.
Have done that on a few cars.
Once done tho, you can't turn the fan, not even a millimeter, as it's now hard locked to the fan belt.
So I'd say very unlikely it'll be a screw in the VC body.

@ John. should be able to turn the fan by hand, but it should have an amount of resistance.
Usually like the OP described, try to spin it freely by hand, may only get barely a few degrees of free movement. Even when cold.
But they all vary to a degree.
I know brothers (TD5) is like that, needs some (small) effort to turn to move the fan blades to a location to allow easy fitment of the VC removal spanner.
The TD5 needs more effort than my Tdi does, and the D2 v8 feels like it needs a bit more effort than the TD5 fan does by comparison.

Maybe some VC failures are by design made to lock up, instead of unlock when they fail. Would be preferable actually!

[whitey56]

I just checked mine it spins freely with minimal resistance when cold.
If your motor reaches operating temperature after 3 to 5ks running I wouldn’t be to concerned about it, if it takes longer because the fan is working flat out them maybe replace it or check for a screw.

[Toxic_Avenger]

Not D2 related, but I have had a viscous coupling on a Non-LR car fail and develop a bit of play in the coupling.
This creates a harmonic which ended up destroying the water pump via a bent shaft.
IMO, viscous couplings are service items... every 5-10 years I'd think. They are not cheap, but not blown engine rebuild kinda cheap, if you know what I mean...
200 bucks on a 5 year service is not a deal breaker.

[CU55TM Disco]

Unsure about the D2 fan, but I have refilled my fair share of Viscious Fan Hubs using the Toyota Fan Hub Silicone ($10 a tube at toyota) its a bit of a balancing act to get JUST the right amount of oil in there, otherwise they tend to drive more often than freewheel, regardless of temp.