Quick question...

[MrEdd]

This may be silly and quite trivial, but what's that fan sounding thing that comes on periodically? My dad and I have made every attempt to diagnose it and can't come up with anything. We hear it the best driving steady on the highway ~70mph. It'll come on for 5 minutes or so then fade away. It sounds like an electrical engine fan, even though the engine fan is mechanical.

We think it could be something to do with the A/C because it's not blowing at it's full capacity.

[DmaxMaverick]

Probably is the engine fan. Although it's mechanical, increased coolant temp will cause the fan clutch to engage. Could be normal, or it could be an indicator of a developing cooling issue. If it's always been like that, and hasn't increased in frequency under the same conditions, I wouldn't worry about it.

Could be an A/C issue, also. If the duct is full of leaves, etc, they could be making noise at the squirrel cage fan. A failing fan usually squeels. There are some common issues with low air output, but I haven't heard of one accompanied by additional fan noise.

[Hubert]

Yep 2nd the AC vent. What vent setting is AC on? On defrost OR on feet and defrost both heat and cool are open and working to dehumidify the air and direct it to windshield. I sometimes get a loud fan noise until some flapper inside shuts fully. Might try playing with ac controls to see if it affects it.

Clean radiator from bugs and trash and watch temp gauge to see if you notice anything. Any loss of power would inicate clutch engaging on radiator fan.

[MrEdd]

My temp gauge floats around 200. That never changes with the noise. I also keep my fan setting to chest/feet or just chest level 90% of the time. Nothing about the A/C performance seems to change with the noise. I sort of think its the engine fan's clutch or something...