I bought a used 2003 Honda Civic Hybrid with a little under 60K miles on it recently. I took it to a mechanic, ran CARFAX and everything checked out ok. The car drives absolutely beautifully.

I've noticed that sometimes, when I turn the car off, something is still running under the hood--it sounds like a fan. I'd say this only happens about 1 in 4 times I stop the car. If I restart the car, and then turn it off, the noise always stops. I've waited for 10 minutes and it has not shut off by itself. I read the driver's manual cover to cover and it doesn't mention anything about this so I don't have any reference point of how to tell if it's normal or not. I've talked to a couple other owners of the same model and they all have the same experience. One person told me that the noise will turn off after 20 minutes on its own; another person told me it's a fan.

Does anyone know what this is? Does anyone know how I can get some sort of "official" statement about what this is? I want to know what is going on...if it's something I should let run...or if it's something I should continue to turn the car on and off to stop? Or if it's a sign something is wrong? I don't want to just go on word of mouth here.

Thanks!