What is the problem if my coolant reservoir is steaming hot?
My car has 230000 miles.
My car has a manual transmission.
Hi there. Most of the time when you see "steam" coming from the overflow tank, it’s due to higher than normal or overheating problems within the coolant system. As you know, when coolant and water reach "boiling temperature", water evaporates into steam. The coolant overflow tank has open space, where hot "vapor" has a chance to turn to steam. If your car is overheating, this is something that should be inspected by a local mechanic. If the temperature is good, it typically does not indicate a problem. However, remember this; as coolant and water evaporates into steam, it reduces the amount of coolant inside the motor; so make sure to keep the reservoir full to the indicator line when the car is cold.
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