02 02 altima v6

i dont have a lot of info on this car it belongs to a friend of my dad but he said it makes a roaring noise from the engine this noise goes away for about a month after an oil change and the engine light comes on every now and then but goes out with in a day havent looked at it yet but if you guys know of anything i should be looking for let me know

thanks in advance

How many miles on it? For the check engine light go to a Autozone or Oreilley Auto and get the codes it shows and that will give you a good starting point.