My radiator fan runs all the time making a roaring sound but the fan clutch is not locked up. Anyone know if the clutch could still be the cause or what else it might be.
the resistance is about the same as the new replacement part I bought.

 

What kind of car is it on?

 

It's a 71 cutlass supreme that I swapped the 350 for a 455 out of a boat. Used my water pump and fan from the 350 and I don't recall it making that much noise.

 

It's a 71 cutlass supreme that I swapped the 350 for a 455 out of a boat. Used my water pump and fan from the 350 and I don't recall it making that much noise.

 

When I think of a roaring sound I immediately think of an aircraft engine, an everglades swamp boat, the roar of a tiger, a bear or the roar of the engines at the Daytona 500. Is it that type of roar you hear? Is it possibly the roaring sound you might expect even from a simple fan turned on high, or with turbulent air flow? If that's the case, did you replace the fan shroud - maybe that is or what's contributing to the sound? Even a fan mounted to closely to the radiator (e.g. not at an optimal distance) can contribute to a roaring sound. Really tough to say without hearing it first-hand.

 

I decided to replace the old clutch even though is wasn't locked up. The new one works now and I can actually hear the motor.

 

Oh, OK....so it was the clutch. Glad you resolved the issue.

 

Most of the aftermarket fan clutches sound terrible. Like an 80’s Chevy Van I used to drive for a Supermarket. Loud roar is terrible.