1999 Other Saturn Models Am I getting ripped? Engine replac

2 months ago I paid to have an engine replaced (teen daughter failed to put oil in old one!). It was a used engine with 50,000 miles on it-standard 1 year warranty and 90 day labor warranty. The engine light came on on the way home, we took it back and it was a coolant sensor of some sort that was replaced the next day. A few days ago she went out to the car and the coolant was in a puddle under the car. The shop says this is an accessory and not covered under either warranty. The mechanic told me that he pulled the water pump off the old engine since the one on the replacement engine looked leaky. I think at best I should have had the option to put on a new water pump at the time or to pay for one now and not get charged for labor. I would appreciate any thoughts in this! Thanks! Juli