First I would try an OEM Toyota oil filter to see if the start up noise goes away, if it does then that's your problem. Non OEM filters will drain back and you'll get a rattle at start up until the pressure comes up. If it still makes noise then it is the tensioner. Don't try heavier oils this could cause pump failure making for even more problems. Toyota designed the pump for the recommeded oil viscosity, a higher viscosity will make it have to work harder to push the oil through. Plus a 5w will circulate quicker than a 10w.
