The noise won't matter until it fails and then you'll know it as it'll be too late. Mine made absolutely NO noise and then started a slight 'ticking' that progressed to a louder noise that then became a 'chirping' noise .... all in less than 10 to 15 miles .... everything in the cam chest had to be replaced at that point....so according to that, you have to pre-emptively change them out or bite the bullet once they go with much more expense. If you're under warrenty....ride on, unless you're afraid of being left on the side of the road. If you're out of warrenty, you may want to adopt the mindset of changing out internal parts (lifters) as a maintenance item on a mileage schedule. I'm still having trouble wrapping my mind around this, but have just learned a expensive lesson that has me leaning in that direction. spyder