It is possible the head gasket is leaking, should be loosing coolant as well. Valve seal leakage is fairly common on this engine but usually with high mileage. Try switching to a high mileage oil may help. My 2002 same eng. does the same thing but the cost /time for seal replacement aint worth it and i can do it myself! Wont hurt a thing, unless smoking all the time. Just keep a check on the oil level, mine doesn't use any oil but i change it, about, every 3k miles and use Valvoline Maxlife oil.