HMMWV m998 Fan is vibrating

[0311retired]

Good afternoon gents. I've been searching and searching but can't find the answer. As I was pooling to my parking space at work this morning I have noticed some crazy noise from under the hood. After I opened the hood I can see that the fan blades were hitting the cover. It's not doing that constantly but it's pretty bad. The whole fan assembly is vibrating.
Is the clutch going out? Or it is the water pump? I have video of it but because the size, it won't let me to upload it for y'all to see.

The big question is: is it safe to drive home? About 12 miles trip.


Thanks a bunch.

Mark

 

[Action]

with engine off, grab end of a blade and move it towards the front and rear. Does it move?

 

[0311retired]

Nope. It ain't moving. I've also noticed that when I start it up the fan is always running. Full time/ no breaks.

Action, thanks for your help.

Mark

 

[NDT]

What is "the cover"? Is that the shroud?

 

[0311retired]

Yes. The shroud.

 

[Action]

the fan will always spin just from the movement of the parts. I dont reccommend it, but i have stopped it from spinning with my hand. it is very different when activated.
Start it up and then unplug the connector near the washer fluid bottle. That will make the fan kick in.
The cooling stack is somewhat adjustable. Look to the rear most part and find the brace on each side holding it up. You can adjust some there. The shroud itself will move slightly forward and back with the screws down each side loose.

 

[0311retired]

Will try that. Thanks for your help!

 

[86humv]

There's also a bracket that attaches to the shroud / radiator lip on top....make sure its there.

 

[0311retired]

Yes, the bracket is there.

My local shop is saying that it's the clutch or water pump. They said that they will replace both parts.

 

[3000gt]

Fix it ASAP Ca user that bastardo will find a way to break stuff.

 

[Bulldogger]

If it is the water pump, you should see weeping or you will be able to wiggle the fan assembly on the shaft of the pump. It would be rare but it sounds like your fan might be coming loose from its mounts on the clutch. But again it should wiggle when the motor is off. If you don't have any wiggling , then it sounds like trouble with the shroud assembly itself somewhere.
On the fan clutch assembly I have taken apart they used a tremendous amount of thread lock , and plenty of torque so that'd never come apart on its own. But a lot of our vehicles were maintained by people who just wanted to finish and leave for the day.

I will cross my fingers for you that it is an easy and inexpensive repair

Bulldogger

 

[0311retired]

Bulldoger, I hope you are right. I'll definitely check the fan assembly.

Thanks for your input.

Mark