ridethe907

ridethe907 t1_iutnaxa wrote

Maybe in some trucks, probably semis. DEF tanks in modern consumer trucks are heated too, but not by the block heater, and that stuff will freeze solid if it's cold enough. In your typical 2500-3500 series pickup the fuel in the tank will be heated when the truck is running, but by hot fuel recirculating from the return line, not an electric heater. If we're talking about plugging in your average normal person diesel car or truck, the only thing being heated is the block. Some people add additional heating pads to things like the battery, and oil and trans pans. I've never heard of anyone putting a pad on a fuel tank.

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ridethe907 t1_iutl7oi wrote

The block heater in a diesel heats the coolant in the engine block, which in turn keeps the oil and fuel in the engine warm, but it does nothing for the fuel in the tank. Anywhere that gets a real winter switches the type of diesel you get at the pump for the winter season so that gelling is not a concern.

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