Which car oil should I use for Sonata 2004? How much and how often?
There are several factors involved here, such as which engine/transmission your car has (GLS/LX models may be different). Also, what type of driving is done (normal/severe). Before you discount "severe" driving, most people fall under this category and don't even realize it. With that said, according to Hyundai's website, you should be changing you oil every 3,000 miles. It looks as though the type of oil should be a 10w-40 semi-synthetic oil. If you have any question about that, look at the filler cap on your engine. In most cases it will say right on the top exactly which type of oil you should be using. If you are in an extreme cold environment (below -9F), you should consider switching to a 5w-30 during that time of year.