2003 Dodge Caravan

I own a 2003 Dodge Caravan with a 3.8L V6 engine with 33,500 miles. Every so often when I start the van up I get an extra fan hum or something, that increases with the speed of the van. This doesn't happen every time I start the van though. I thought it might have to do with the A/C because it happened whenever I used it, but lately It has been happening when I haven't used it in a while. Any help or suggestions anybody can provide would be greatly appreciated.

Find a really good mechanic you trust, take it to them and have them check the engine. Hopefully its still under warranty. This sounds like what ours was.... if it is kind of like a ticking noise. The whole engine had to be rebuilt at 62,000 miles. The sound was there at 30K but the dealer kept saying it was no big deal. YA Right!!!