While driving on the interstate all the dash warning lights came on and the temp went straight to 120. I was right at an exit and I pulled off and into a gas station lot. I checked under the hood and found that the fan, fan clutch ,fan clutch pulley were all connected but off ( laying against the crank pully) On the back of the fan clutch pulley their was a part (1 inch round with a thin washer that looked like it went into a housing (water pump)? I did not lose any coolant. Of course the serpintine belt was loose with on pulley to run on.

What just failed? What holds the fan clutch and pulley to the waterpump other than the single bolt?