2006 Sonata v6---timing chain tensioner issue?

[AmyS]

Just last Thursday, my husband and I bought a used 2006 Sonata GLS v6 with 41,000 miles on it. We test drove it on Monday, and it made a clicking/rattling noise when I turned it on. I turned it off, realized the AC had been left on, turned that off, restarted, and the noise did not return. We thought the noise had been from the AC fan or something.

We noticed the SRS light was lit continuously, so this dealership took it in to the Hyundai dealership to get that problem fixed. (Replaced seat belt buckle that wasn't sending right signal.) We asked the Hyundai dealership to perform a complete vehicle inspection for us while it was there, and the head of the service department said it was in excellent mechanical condition.

So we went ahead and bought it on Thursday, without test driving it again. Brought it home, and since then, it has been making that same clicking/rattling sound on cold start every time. When you turn it off and start again within a relatively short period of time, it doesn't make the noise again on starting. If it's been over 75-90 minutes, we get that noise again.

I've done some research, and it seems to me (I'm not at all a mechanic, so I may be completely wrong) that this could be a timing chain tensioner issue from the TSB. We've found some reports that people began encountering the problem at just over 20K miles. However, since we just bought the car, we have no idea when the problem began.

Regardless of how long this has been happening (since the beginning or just for last 20K miles or so), does this type of problem cause any big problems with the engine? Or will everything be okay if I have them replace the timing chain tensioner (if that is indeed the problem)?

The dealership I bought it from has a 3-day money back guarantee no questions asked, so I may be able to take it back to them tomorrow and cancel this sale. (Today, Sunday, is actually the third day, but they are closed.)

If this problem could have caused long-term serious engine damage, I may try to return the car. If the consensus is that the engine will be okay long-term, then I'd prefer to keep it, as I absolutely LOVE the car other than this issue.

Thanks for any advice you can give me!
Amy