coolant light on dashboard (2000 BMW 323 i)

most likely just a top up. as the system heats up the coolant expands and lifts the sensor. top it up when cold and it should be ok

Your coolant reservoir should have a level indicator get the level to this mark and your light should not go on. Also be on the lookout for a leak if you notice the level dropping again.

The coolant level in your car is low. The system is just low enough that the normal expansion of the coolant as it warms trips the level sensor and the light goes out. The cooling system should not loose coolant unless there is a problem. The cooling system is a weak point on this vehicle you will want to keep a close eye on it. If you are not very familiar with it have someone who is check it out. This will save you lots of money and headache.

Check for a leak on the reservoir tank or faulty temperature sensor just put pressure on the tank and you will see I had the same problem with 325i 2003, both had to be replaced.

This is very common on these cars. Most likely you have no problen at all and the coolant is just a little low. For some reason This happens about once or twice a year. I used to be a BMW service advisor and we kept coolant in the service drive for top offs

How do you turn the coolant warning light off after the coolant level is fine?