Engine too hot

I feel my car engine is running too hot even for short distance running, say, 10 km!

Following tests were observed:

1. After engine reached normal operating temperature, the lower radiator hose coming from engine gradually becomes hot, so also, the upper resistor hose which runs to the radiator cap. And, finally, all hose gets hot which indicates the proper flow of coolant.

2. Checked the voltage reading of the coolant temperature sensor with multi-meter, and yes, the voltage drops significantly with time, and readings are within limits.

3. Also, checked for Electrolysis on the coolant, the voltage reading is 0.07 volt with engine reached normal temperature.

3. The fan comes in automatically by itself. This is okay. And, all coolant reservoirs and levels are in full quantity. Instruments on the cluster are all normal, and no pulling power loss etc. All okay.

4. Based on above facts, why the engine is getting hot very very soon even for short distance running?