Automotive expert Brad Bergholdt answers reader questions. This week: Should a noisy belt-driven truck fan be replaced with an electric one?

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Q: I have a 1998 Chevy 2500 van with a 5.7-liter gas engine. It has a clutch fan that sounds loud at times, and I feel it is a waste of horsepower. I want to remove it and install an electric one. The clutch fan is easy to turn when the engine is cold, and I guess the clutch engages when the hot air hits it.

A: It sounds like your thermostatically controlled fan clutch is operating properly, since it spins freely when cold and occasionally engages fully. Your longitudinally mounted engine uses a mechanical radiator cooling fan, unlike the electric fans used in transverse-engine, front-wheel-drive cars. You’re correct that mechanical fans require a lot of energy to spin them — but that’s why your fan has a clutch. This mechanism allows the fan to largely freewheel under most conditions — saving gas — and engage only when needed to cool.

Are you driving the van in hilly terrain or towing a trailer? If not, more than rare fan clutch engagement may indicate a cooling-system deficiency, such as a restricted or under-capacity radiator.

Converting the fan to an electric style is possible, though the parts cost and effort would likely not be recouped via fuel savings.

One of several choices is the Zirgo HFM-ZFU16S (3,600 cubic feet per minute) reversible electric fan ($225 at SummitRacing.com) and a high-quality thermostat/relay wiring kit such as the Painless Wiring 30103 ($65, also from Summit).

Another option (if space allows) is to install a smaller, quieter electric fan to supplement your existing mechanical fan. Your thermostatic fan clutch would likely not engage as often, if ever.

E-mail Brad Bergholdt at under-the-hood@juno.com