[sa meredith]

...not even for a second.
22 years of this crap was enough for me.
But just a thought, that I take away from early in this thread...and possibly a lesson.
I'm very sorry, but no, the dealer will not "take your word" for the fact that you did proper maintenance yourself. And you really can't blame them...mostly because the manufacturers (in this case, Hyundai) have specific guidelines for a dealer to make a warrenty claim, and get paid for parts/labor. One of the requirements is proper documentation, if the factory reps request it. And I'm quite certain, "Customer states they did oil and filter changes, and they are not lieing" is NOT one of the applicable choices, under the documentation heading.
In this case, we have an instant red flag...54K in 18 months. Yes, it should be fine (the high miles), and not create an issue...but NOONE can argue that 54K in 18 months is unusual, and therfore a red flag. Just the way it is.
So look at it from the manufacturer's perspective. The dealer can show no history of oil changes done at their place...none. Secondly, the customer can produce no receipts for oil changes done at repair facilities. None. And, at 54k, somewhere between 8/10 O and Fs should have been done...10 in 18 months...that's a lot. What in God's Holy name would they expect the customer to say..."Oh, Oil changes??? No, we never got around to that very much. Maybe 2 or 3, but that's it." Of course noone is going to say that...sorry, THE FACT OF THE MATTER IS THIS... Consumers lie and lie and lie and lie and lie and lie...and think the dealer does not know, and somehow believe it to be a victimless crime, thinking "Oh, the dealerships got plenty of money". Just the way it is...I'm not insulting anyone here...but we have all told companies what they needed to hear when making warrenty claims...whether it be on a washing machine, vacuum cleaner, dish washer, snow blower, lawn mower...whatever. We damage it, and then say "wow, I can't imagine how this happened...now shut up and give me a new one."
So, while I believe this poster indeed did their oil changes, the fact is, because somewhere aroung 10 where required at only 18 months, I can fully understand Hyundai wanting actual, real live documentation that they did occur. If indeed only 2 or 3 where done...yeah, you SHOULD have engine trouble. Any of us could cook an engine in 18 months by driving 54K, and not doing the needed work.
I've always said, go to dealership, spend a little extra and do your maintanence there, and if something comes up, they will be in your corner. Don't just use them for the "free" warrenty work...spend a little bit...it can work out for you. Believe me, in this case, they would love and engine job...it is good revenue. But Hyundai won't approve it. Don't blame the dealer.