well i am no pro, but i guess u should leave it, all japanese cars have there temp at half mark and most have there fans regulated by d thermostat, even when ac is on or off, and nothing has happened to them, worry only when d gauge has left d half mark and is going up, which i doubt it does.

i have a 94 altima, and was having hard starting problems especially at petrol queues. my electrician said it was overheating, and rewired the circuit to make the fan come on at ignition. the hard starting stopped. so maybe if you are not having overheating problems, leave it alone.

ahh BLACKMAN

nkc has just described how the electric coolant fan works.

All IC engines have an optimum working temperature. The job of the thermostat is to get to this temperature as fast as possible and then to maintain this temperature.

Meanwhile there are two "Thermostats" in engines which has electric coolant fans. The first is a mechanical one which actually seals the coolant in the engine and physically prevents it from going to the radiator. (This is the one that our road side mechanics usually remove). As the engine gets hot, it opens up and allows the coolant to flow to the radiator. If this flow is insufficient to keep the coolant at the set temperature, the the electrical thermostat comes in and puts on the coolant fan. (The coolant fan just blows air over the radiator and brings the temperature back down.) in cold countries, it can be so cold that you dont ever use the coolant fan. Infact, people actually get extras to cover up the radiator and prevent cooling since its so cold.

If you have a faulty mechanical thermostat, a sign will be overheating. as the coolant is prevented from circulating. OR over cooling as the engine never warms up to its optimum operating temperature.

In all cases, its best to have a hot engine at its optimum operating temperature. as this means less friction, better combustion etc.