I didn't drive my car for 3 or more weeks. When I started it, I heard a valve clicking and immediately turned it off. A car mechanic advised me to add about one-half quart of marvel mystery oil and run the car five minutes. I did and, unfortunately, the clicking continued.

What now? Should I try a valve adjustment? What are the chances this will stop the clicking? If it doesn't, what's next? I have heard the term valve job, but not sure what that means.

Also, any information about what a valve adjustment or more extensive valve work could cost will be appreciated.

My main questions are about the valve clicking, but I also am interested in opinions related to selling this car. I want to sell it as soon as possible. It is a 1989 Mazda 626 4-dr (auto, AC). It needs new paint (trunk, hood, roof) and a new radiator (there is a 2” slit in the top of the radiator). Recently the car got new brakes, new alternator, and new battery. It has never been in a wreck, not even a fender bender. 125,525 miles.

Should I try to sell the car “as is,” or first try a valve adjustment? More extensive valve work? If a valve adjustment cures the clicking, should I try to sell the car before installing a new radiator? As you may guess, I don't want to spend more than the car is worth.

Any help will be greatly appreciated.