Hi, I am not a car person, but I am getting conflicting messages from mechanics so I thought someone here might know the real deal. I have a '95 Volvo 960, a handmedown from my dad.

Over the summer, my low coolant light came on with increasing frequency. At first it just came on when I turned the car on and then it went off soon after. Then it came on for longer and longer. I (ok, my boyfriend) added more coolant a few times which held the problem off for a bit. Finally, when the coolant light was really screaming and my car seemed to be heating faster (it never went into the red zone thankfully) I bit the bullet and brought it into the shop. The mechanics tested the coolant pressure system and said that the tubes were fine and so the problem must be in the radiator. Then I shelled out about $500 for parts and labor for a new radiator. The mechanics now claim that they did find a hole in the radiator after they took it out.

But now, about a month and 1500 miles later, my low coolant light has started to come back on when I turn the car on! So far, it goes away within a minute or two and the car temperature doesnt seem to be getting any hotter but I am afraid it will get worse.

The mechanics suggested a few explanations
1) the radiator is a lemon. this would be good, because it would be covered by the repair warranty.
2) there is a leak somewhere else in the coolant system. this would cost $60-$100 to diagnose at a professional shop, before any repairs. incredibly, even though the mechanic originally did this diagnosis, said all was well, and charged me $500 for a radiator, this would not be covered under the repair warranty.
3) there is an electrical problem causing the light to go on. this could cost a lot just to diagnose.

Does anyone have any idea what is most likely here? Any advice as to what to ask them to look into/wait on? The radiator pretty much blew my grad-student-car-care budget so I am trying to not throw too much more money around without knowing what I'm getting into.

Also, my own thought is perhaps something is wrong with the physical gauge in the coolant system. Is that possible?

Thanks,