I would check the valve cover gaskets. With 170k miles, if they have not been replaced, then they need it. My passenger side was leaking and it would smoke some out of the scoop and hood. Clean the whole area real good then go for a drive and see. The issue with some oil leaks like that is a little bit of oil will make it look like a huge leak. The best way to check the bottom of the valve cover is through the access door behind the passenger wheel where the O2 sensor is.