2008 HHR drove through some water today. When the A/C is on the electric fan/radiator assembly shakes so bad it looks like it is going to rip out. When the A/C is off the fan doesnt run at all and the engine will over heat. It cant be driven at this point. Thanks for your help.

 

With the vibration you describe when the fan is running, it sounds like one or more of the blades are cracked/broken. You are likely looking at needing to replace the complete fan.

But, first give it an eyeball with a flashlight and check out the blades, and also check the mounting for the fan, as well as the radiator itself.

Good luck - let us know what you find.

 

X2, sounds like that water damaged the fan blades or snapped one off entirely.

P.S. to the forum!

 

The fan runs continuous when the AC compressor is engaged. AC mode or defrost.
With the AC off, the fan may not be on. The fan will only power on when the engine reaches temperatures that will turn it on.(can't remember the exact temp) Saying the fan won't come on and it will overheat, may not be exactly correct.

As far as the fan shaking. I agree with whopper and Mike about checking the fan blades for broken or cracked areas.
I will add to also check the mounting points for the whole assembly. If you splashed a large volume of water in there, you could have dislodged or broken the entire assembly from it's mounts.