I have a 2007 hyundai Sonata. Under the hood there is a sticker on the engine coolant reservoir it says to measure coolant levels while the engine is cold. When I do that, the coolant levels are low.
In the owners manual it says to measure coolant levels when the engine is warm. When the engine is warm the coolant levels are correct, within the min and max lines.
Which one is correct? Should I go by the official manual or what is written on the engine coolant reservoir on the car?
What is the higher risk, too much or too little coolant? If I increase it to the minimum when the engine is cold, will that damage the engine if after warming up the level increases beyond the max?