The obvious is that you need one of these:
Amazon.com: ERUSUN® v1.5 Bluetooth Mini Small Interface OBD2 Scanner Adapter Compatible with Android / Droid Torque: Home Improvement
Or perhaps a Ultragauge/Scangauge. Your block is too much if you're causing the radiator fan to come on frequently while moving. You can tell if it is with an OBD scanner, or perhaps (if you're handy with wiring) with a small LED.
Do you have any instrumentation to monitor FE yet?