Sounds like your fan clutch is failed. Or perhaps the four 10mm bolts holding it in are loose. With the radiator shroud unfastened and moved out of the way it is accessible in site but not without a lot of squeezing and vigorous cursing. Good luck!

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.