Radiator Leak
 

I bought a 2002 Boxster S last year with 18K miles, now has 21K miles. Took it out of winter storage and to the dealer for routine service in early May. Since bringin it home, it has been leaving drip marks on the floor which I thought was just residual drips from the oil change, fluid top offs, etc. Then the "Engine Coolant High Temperature" warning light started coming on; even though the engine temp guage shows normal 180F. The leaks on the floor were getting bigger, so I got under the front bumper and traced the leak to a long radiator running along the center front of the car, specifically to a little blue plug on the lower drivers side. (there was a visible drip on the blue plug) When I reached in and touched the plug it fell off, along with a brass washer; no wrench, no tools, I simply touched it and it fell out. This little blue plug has a hole through the center, so I'm assuming it is a bleed as well. It is obvious that it was twisted off (broken) at some point. (The coolant never dropped below the "minimum" mark)

Anyway, I had it flat bedded to the dealer this afternoon and they have since called me tonight to say that the radiator is "damaged" and will have to be replaced. They were not real clear on how it was damaged or what exactly is broken. When I explained that it had leaked since being in their shop, they said that it had over 200 miles on it since it was there and I must have hit something. (The dealer is 40 miles from my home, so its not hard to put 200 miles on in a month.) When I pressed them for more info they said they would get back to me with a price.

There are scrape marks under the front cowling (that were there when we bought it), but nothing new and nothing appearant that would indicate possible damage to a radiator.

I'm suspicious that they may have damaged it during service. My question is this - is that little blue plug on the radiator involved with routine service?
Is it possible that simply removing the remains of the little blue plug and inserting a replacement would cure the leak? (Even after the plug fell out, its still a slow drip) But what about the "Warning Light"? Is it fair to press these questions to the dealer?

Sorry for the long post and thanks in advance for any assistance.