If the engine is quite worn, and has large clearances, the 0W30 might make it WORSE, since this stuff is extremely thin and slippery. Synthetic oil manufacturers often issue a warning about valve lifter noise when using synthetic in an older engine. If I were you, I would go back to a regular 5W30 mineral oil for one oil change to see if it improves. If not, you need one or more valve lifters replaced if you want to get rid of the noise. Most people just keep driving and put up with the noise. Your engine is not in danger. Replacing valve lifters on your engine is not difficult.