Very Noisy Heater Fan Help!

Hi,
Took my Disco through a car wash yesterday on the way home got this terrible low rumbling type noise and vibration thought I was about to break down then my wife turned the heater fan of and it stopped.
I would like to take the blower fan of to make sure nothing has fallen onto the fan causing it to become unbalanced.
Can this be done without draining down the whole cooling system?
I just want to be able to see the Blades of the fan.
Thanks for any advice.

What Disco is it.

did it fill with water by any chance??

My heater fan started making a right rattle noise recently. I put up with it for days and it was driving me mad. Eventually I got fed up and leaned over to passenger side footwell and gave it a bang with me fist............it stopped ! :doh:

What disco is it?
On my disco 2 i had the same problem. The heater fan is under the glove box. Remove the card trim from under the glove box, 3 screws hold the motor in, disconnect the wiring plug and out it comes. Mine was full of leaves, but i stripped the motor and greased the bearings while it was out. Its really quiet now and no vibrations.
Mark

Hi all.
My Disco is a year 2000 TD5.
I think on ready the replies that I will remove the heater fan as I suspect some rubbish may have got into it.
I recently had the windscreen refitted and it is possible that a bit of old mastic has found its way into the air intake.
Thanks to everybody that replied, I will post the outcome of my investigations.

Hi All.
I have taken the fan motor out today and removed a piece of rubber about 4 inches long which was resting in the fan body.
The result was the fan was unbalanced and vibrated badly.
I have put the fan back in and all is now quiet again.
Thanks to all who sent helpful suggestions.
Regards ron