Thank you, everyone, for all of your responses and advice. I can’t tell you how much I appreciate all of these “second opinions.”
[list]The check-engine light has not come back on, so, indeed, it may have been the gas cap that triggered it.[/list]
[list]The dealership replaced my coolant, and I will continue to check it every few days to make sure I don’t lose another half gallon without realizing it.[/list]
[list]Next paycheck, I’ll take the car to a local garage (recommended by co-workers) to talk about the water pump, timing belt, smoke test, and other upcoming and imminent maintenance. If we can hold off for a few months on any major repairs, I’ll be happy.[/list]
In the meantime, there was a new development Friday night, possibly entirely unrelated, but I wonder: I left work Friday to find my fog lights had been on all day. I’m not sure how they turned on, as I haven’t used them for probably two years, but on they were. And they wouldn’t shut off. I tried every trick I could think of, called my dad, called a friend, called the dealership. Of course, the service center was closing, so they couldn’t help me. I was told to return Saturday morning, when they could “probably remove the fuse at no charge.” I was assured that this had nothing to do with anything they did to the car on Thursday. I asked if there were another service center that could help me, or if removing the fuse was something I could do, and was told no, that it was too difficult. About two hours later, a friend removed the access panel to the fuses located inside the car, beside the steering wheel and pulled out the fuse in about 15 seconds. He’d found the directions online.
I realize it’s a little thing, fog lights, but I’m hugely bothered by the service tech telling me that pulling the fuse would be too difficult when it clearly wasn’t. In addition to the points you all have made, this is yet another reason any information he gave me is suspect.
Regardless, I feel 100 times better now - because of this “discussion” - about how to approach this repair work and how to better inform myself (and arm myself) when I go to the garage. Thank you so much for posting your experience and expertise on boards like this for car morons like me!