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Yes, it can. The clutch is designed to engage at a certain temperature, which then allows the fan to pull more air through the radiator. Below the determined temperature, the fan just sort of free wheels, and the only air you get is what is pushed through from driving. That's probably ok when driving, but not while stopped.
The spring is just part of it. There is a valve inside the clutch. And there is a fluid in there. At the determined temperature, the valve opens (or closes - don't know which) and the fluid flows (or stops flowing), locking the clutch and engaging the fan. Usually these fans will roar when you first start them, because all the fluid has settled. After running for a little bit, centrifugal force moves the fluid, the clutch disengages and the roaring stops. Actually, newer fan clutches are electric.
Never heard about the newspaper test. The only test I've heard of is spinning them cold by hand. They shouldn't spin freely.
Paul
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