Toyota Repair: 90 Cressida

Question
Aloha Ted, the overflow coolant reservoir of my Cressida (110,000 miles) keeps getting low and I have to refill it with about a pint or so once a week. I see no visible coolant leak anywhere and the car does not smoke. The oil and coolant look normal too. Could this be a cylinder head gasket starting to fail? Mahalo.

Answer
Hello, yes it could be  a headgasket starting to leak into the combustion chamber, a small leak is usually hidden due to the coolant being burned in the combustion process, it is commonly at the #6 cylinder, what you can do at this time is to replace the radiator cap, it may not be holding pressure then see how it goes, if the problem persists have the cooling system pressure tested, if the cooling system loses pressure over a time of a few hours there is a small leak somewhere, you should also do a internal combustion leak test, you can do so yourself by buying an inexpensive test kit from the auto parts store