View Full Version : Bad/ Intermittent Fan Clutch
08-04-2013, 05:50 PM
Drove all the way to Kelly Flats for a family run ( 3 Runners), conquered Heart Attack Hill, and then she overheats.
Saw a loose heater hose( steam coming out), re-clamped it, topped off the coolant and started engine. Wish we would have closed the hood before we started her back up, because that is when we saw that the radiator fan was not turning. Let it cool down some more, tried turning the fan by hand and it just wouldn't turn clockwise.
So we turned around, heading back down hill and to the safety of highway driving without a fan. I watched the temp the whole way and it held steady. Got down to bottom, opened the hood and the fan was working just fine.
Question: Was it the loose hose that caused the overheating and the fan was working as engineered or did the intermittent fan cause the hose to pop a misplaced clamp?
Time for a new fan clutch Justi n case??? I have read that they are suppose to turn smoothly with the engine off??
... because that is when we saw that the radiator fan was not turning.
Let it cool down some more, tried turning the fan by hand and it just wouldn't turn clockwise.
Sorry, not familiar with these vehicles, does it use a fan clutch or electric fan. If its a fan clutch, can you clarify the above? How did the fan not turn when the engine was running, but then you couldn't turn the fan by hand when the engine is off?
Not much help, sorry.
08-06-2013, 11:53 AM
Fan clutches are pretty simple - they have a bimetallic coil inside that operates a valve for the silicone fluid inside. Above a certain temperature they lock up, below that and they spin somewhat freely. Like an electric fan, they are supposed to only run when needed. The failure mode for old clutches is the fluid gets thin and won't lock up or it leaks out. Other than a new clutch, you can simply replace the fluid, it is available from Toyota.
Yea, I think that's what I was trying to get at. For the fan not to spin while the engine was running, it would have to be free-spinning, IE no friction in the fan clutch (low oil, low viscosity, valve not opening, etc). But then to not be able to spin the fan by hand when the engine is off(not to mention in only one direction), means it somehow locked up? Those two didn't seem to make sense to me?? Then again I am easily confused ;)
Oh well, free bump! :D Hope you can get it figured out Tom!
08-06-2013, 12:45 PM
If the fan would not turn clockwise, that's the opposite of the way you want it. Consider that the engine turns clockwise as you face the front of it. The means that you want the clutch to lock up in the CCW direction in order for the pulley to spin it clockwise. I've never been around one that wouldn't spin clockwise though, that almost sounds like something is broken inside the clutch.
I remember reading a piece in Tech Exchange in Toyota Trails where Mark Whatley talked about crappy aftermarket fan clutches, he went through someing like 3-4 of them new out of the box that didn't work. I think the moral of his experience is to pay a little extra for the genuine Toyota part.
08-06-2013, 06:52 PM
It wouldn't spinning while engine running right after it overheated ( hose popped off). Then after refilling, and driving it a bit( trying to limp it to the road, it very overheated. And when I looked it was turning. So I guess,cit locked up when hot, and the started to turn again as it cooled down. But it definitely didnt turn by hand CW... But would CcW...I'll just keep my eye on it
08-06-2013, 06:59 PM
It wouldn't spinning while engine running right after it overheated ( hose popped off). Then after refilling, and driving it a bit( trying to limp it to the road, it never overheated. And when I looked it was turning. So I guess,cit locked up when hot, and the started to turn again as it cooled down. But it definitely didnt turn by hand CW... But would CcW...I'll just keep my eye on it
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