Viscous Clutch Fan issue - rb30 but may not be engine specific

[Throbbinhood]

So, during a recent trip away, had an odd issue pop up.

Fan was fine first week of the trip, operating normally, would whirr on startup, release after 30s or slow, then I wouldn't hear it unless I was really loading it up up a hill (billy goats) or letting it idle forever. Temps were always fine, never got over 85c (even fully loaded up billy goats and I was in a hurry haha).

Then, one day, the fan just stopped releasing. So now it's always on like it is at the start, whirring away loudly even at highway speeds. The motor isn't hot, in fact the fan being on so strongly means it takes FOREVER to get up to temp. I thought maybe my temp gauge died, but you can audibly hear the fan noise at hwy speeds, whereas I couldn't before, it simply doesn't unlock anymore.

So, what does this mean? I was thinking maybe fluid, but I thought low/absent fluid usually resulted in it not locking up, not the other way around. Any thoughts?

[mudnut]

How far does the fan rotate when you try and spin it by hand?

[mudski]

Sounds like the hub has just seized. Can you see if you can split the hub in two halves? Should be maybe four bolts on the front side of the hub if so. If you can try re oiling it. No sure how much is needed though.

[Patrol'n]

Had a similar issue with mine a while back, it was weird as it would randomly lock when the engine was already warm, you could instantly feel the drag on the motor and couldn't really ever maintain operating temp when it happened.

I ended up replacing it, (I was told by a mechanic I know that they stopped trying to service them as the repairs often didn't seem to last that well).

[Throbbinhood]

Sorry, forgot to reply and car has been sitting there.

Yeah, when you turn by hand, it goes as far as you can push it and no further, she's tight!

Haven't gotten around to pulling it off yet. Life n that, ya know.

[dom14]

Sorry, forgot to reply and car has been sitting there.

Yeah, when you turn by hand, it goes as far as you can push it and no further, she's tight!

Haven't gotten around to pulling it off yet. Life n that, ya know.

Hey Chris,

Mine goes about a quarter turn before it stops(when I give it a quick turn by hand).

What did you mean by "it goes as far as you can push"?
Does it turn a quarter or half turn and then engage the clutch and not disengage it at all?!

I would take the fan out and give a go at rebuilding it.
I would probably use brake cleaner, thinner or petrol and then dry it out in the sun rather than using WD40.
Before, filling it with the silicone liquid, see if you can find out whether the thermal valve is bad or not, perhaps by applying bit of hot air using a hair dryer.

The second video below shows a guy rebuilding it. Fairly easy and quick job. Well worth a try I reckon.
The silicone liquid isn't that expensive afaik, so have a go at it and let us know. Open it up first, clean it and check the thermal valve. If the valve is bad, then filling it with silicone liquid won't help.
I would even give a go at fixing/replacing the thermal valve(the bimetal thermal coil), just like the way I fixed the RB30 Nikki carby auto choke, but that that's me.

https://www.youtube.com/watch?v=UwM4OqsLek4

https://www.youtube.com/watch?v=zjhKr5usjaA

It's a little repair job well worth your time I would say, 'cos fairly easy and quick.
New clutch is pretty pricey and a wrecker one can be a hit and a miss.