It began with a mild ticking sound under the hood. A couple of days later, I was driving from work to the pharmacy, and noticed the sound got a little louder. Then, when I went to leave the pharmacy I noticed the noise got louder as I pressed the gas. My tibby is a manual, so of course I have to press the gas to reverse and the noise just got louder and quicker. If I removed my foot from the gas it was a steady ticking sound. I drove home and asked my husband to meet me outside as I pulled into the driveway. I could tell by his face that I wasn't exaggerating about the sound. I had my brother who is going to school to be a mechanic come over to see what his opinion was. He said to take it to the shop. I dropped it off at the Hyundai dealership. They told me I needed to replace a belt and everything was good as new. My husband dropped me off and we tested the car prior to leaving. Extremely disappointed... they had not fixed the sound at all! We left the car again. This time, they told us exactly what my brother had said. Something to do with the hydraulic lifters. So their way of fixing the problem was to add marvel mystery oil. At first, it only lightened the sound. It wasn't until about 1000 miles after I changed my oil again that I realized the sound has come back again. My brother couldn't believe they added that stuff to my car and told me to immediately get another oil change to remove it. Of course I never did because my father in law swears that the stuff is great. I guess I will have to continuously add it if I add it back and see if that helps again. Otherwise, the dealership said I would have to pay to do engine work and the car wasn't worth the expense.