Ive have always run havoline in my cars and trucks, and I change my own oil every 3k. My mechanic and his son always give me a bunch of [censored] for using it, even though I have never had any engine problems. They say the best dino oils are pennzoil or valvoline(But I am planning on switching to maxlife in my wifes car on the next oil change due to the high miles and all the good things Ive read about it).So long story short, are they just giving me a hard time or is there any truth in what there saying?