I checked the level in the coolant reservoir because the temperature gauge went up to nearly the red zone while I was driving uphill. Right now, the engine is hot so I can't open the radiator cap but I can see that the level of coolant in the reservoir is well below the "add" line. I can easily just add coolant to the reservoir but I don't know if I should also open the radiator cap in the morning when the engine is cold.
My car has 86800 miles.
My car has an automatic transmission.
You’d better just wait until it cools off so that you can look in the radiator. Filling the reservoir will not help in an overheating situation. It may take an hour or two for the engine to cool off enough, but you risk injury if you open it now and you may do some expensive damage if you drive it while overheating. When the radiator is cool enough to where you can touch it you can top off the system If your car continues to have a problem with overheating, contact YourMechanic to have a technician come out to your home or office to check out your overheating problem and advise you on what to do next.
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