Intermitant coolant leak

[daveccpa]

So I noticed a small amount of coolant leaking from underneath the car a few weeks ago . The puddle was behind the drivers side door. It was maybe 1/4 cup. I took the car to my mechanic who looked it over and couldn't find anything leaking. He checked all the hoses the radiators, the water pump etc. He suggested I replace the coolant tank cap which I did. He drove it for a day and couldn't find any more leaks.

I drove it for a few weeks as well with no problems. Then my wife takes it on an extended drive on Saturday (about 75 miles) and on her way home the temp light starts flashing. She pulls off and adds coolant and drives the rest of the way home without problem (20 miles). The temp never got about 185 so I think she got it before any damage. When she parked it there was a small amount of coolant leaking but stopped once the car was off.

There is no leaking in the trunk that I can see and the trunk is dry. However, I'm thinking it probably is the tank. Does these tanks when they do leak have intermitant leaks or do they just crack and drain.