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Mechanical fan sucked into radiator!


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The fan essentially IS a propeller. But ... the fan used on the XJ and MJ has a heavy center section, to which thin, stainless steel vanes are riveted. The vanes are flexible. The reason is to allow them to move more air at low RPM but to flatten out at higher RPM, reducing the parasitic drag on the engine when cooling isn't as necessary. And then there's the fan clutch, which also reduces fan velocity at high speed.

 

I suppose it is possible for the fan blades to get bent forward into the radiator, but I've been on wheeling trips that saw water up to the top of the grille and I have never seen anyone have the fan get damaged. Between the blades flexing and the clutch de-clutching, I don't think it's an issue.

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I imagine with enough drag from the water, and the clutch, the fan would barely spin at all.

 

When my motor and transmission mounts were bad I had a problem with the engine shifting forward under load. Climbing a steep hill the fan ended up eating first the shroud, and then later the radiator itself.

 

Somewhere in my build thread I also have a video of my "Mexican jumping 4.0" taken at that time.

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It does happen if you are stupid and hit the water doing mach 2.

 

If you go into it slowly and allow the water to stop the blades from spinning you will not have a problem.

 

If you it hit fast with a hot fan clutch, there is a very real possibility that it will get pulled into the radiator.

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It does happen if you are stupid and hit the water doing mach 2.

 

If you go into it slowly and allow the water to stop the blades from spinning you will not have a problem.

 

If you it hit fast with a hot fan clutch, there is a very real possibility that it will get pulled into the radiator.

This makes since, also, now thinking about it, once water hits the clutch and cools won't it disengage? I've never sped into water crossings, its just not a smart idea, so this probably won't be an issue for me.

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I myself would think that this would be more of a problem with electric fans as they are mounted VERY close to the rad body. The solution Ive heard is to mout pusher fans outside the radiator, that way when it get to water, the fan pulls away from the rad instead of being sucked in.

 

 

If you're using electric fans, it's a simple procedure to wire in a switch to turn them off for water crossings. :thumbsup:

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