Dodge Repair: hub fan: 08 Ram, gasoline engines, gas mileage

Question
I have a 2008 dodge ram and the "hub fan" runs continually. I have had the dealer fix this once in December 2011. And it is happening again. This causes the truck to burn gas like crazy.
I am not sure if this matters so I will mention this as it is the only other strange thing that happens with this truck. When I start the truck the motor runs around 1500 to 1700 RPM and I have to wait for it to calm down.

Answer
Hi Barbara,
The viscous fan on the gasoline engines is self-thermostatically controlled. There is always going to be some minor rotation speed when the temperature of the radiator is such that it is not 'engaged', but the theory is that when the radiator temperature rises that will be sensed by the viscus drive and engage the fan to the hub fully. There are some specifics about evaluating the fan in the manual which I can copy and attach to an email which I will send to you directly. If you want those pages send me a PRIVATE follow-up question wherein you tell me your email address. If you don't make it private,the address is automatically erased and I won't see it.
I am a bit surprised that the gas mileage would be affected drastically by such a fan so that may not be the cause. Have you tried to get the fault codes, for free, by going to an Autozone parts store and ask them to get them for you using a code reader? Let me know the 4-digit fault codes that they find to be present. That might also explain the initial high speed idle.
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Thanks,
Roland