Best time and how to check coolant container
Best time to check is when the car is cool to the touch.
Locate the coolant reservoir. Locate it can be in the front of the car, on the side, or some where near the firewall.
Once located, clean off excess dust on the reservoir and look for the low and high indicator mark.
It should be in the middle of the 2 marks. If its low, you might have a cooling system leak or the coolant to water mixture is off balance and the water has evaporated which will require system flush. Improper coolant mixture can cause engine overheat or over cool.
If high, remove the excessive using a section pump or loosen/remove the drain valve under or on the lower side of the radiator. Over filling the coolant system can result in excessive pressure build up which in turn causes the system to erupt at its weakest point.
It will be transfer to the overflow tube and drain to the ground on older vehicle which can be a mess.
Recommended change: 24k or 2 years, newer cars are equipped with longer life fluid that does not require changing until 100k or 10 years.