I just bought a 1992 4runner with 165k on it. Runs and drives perfect! But I have some oil leaks. I am having 2 silver dollar sized spots on the driveway each time I have driven the vehicle and then parked it. I put in a quart of oil recently and this is only about 1000 miles since last oil change. It is the 3.0 v6, is it a HUGE undertaking to get to the valve covers?(this is the place I see oil running down the back side of the engine) Is it worth it to stop this amount of oil from leaking? Is that Stop Leak product harmfull for your engine? Thanks, Chris