Hello, I am new to ford, and new to this website.. I just bought an 2001 focus se 2.0 zetec from someone and on a cold engine, it has some tappet noise of some sort. i did an oil change with 10w-30 oil. did I go to heavy? after the car warms about i can barely hear it? would you recommend lucas synthetic oil stabilizer with a new thinner oil change? thank for you help!