This is a revised version of my post in the A4 B6 Forum as it could apply to many more engines than my AVK. I have 174,000 miles and recently I detected a tapping noise (listen to movie below) coming from the area of the passenger side valve cover. Based on my research in this forum, it could very well be either the chipping of a camshaft lobe or a broken lifter. If this is the case, what will happen if I just keep driving without having it repaired? It doesn't seem to make sense to fix it as the $1500 appraised value of the car is less than the $3000 estimated cost to repair.

Will the tapping continue to get louder until something breaks?
What do you think the failure mode will be?
A broken spring, a bent valve, valve that stays open or one that won't open. Camshaft shear at the bad lobe/lifter?
What I am really trying to determine is if I continue to drive the car without correcting the source of the noise, will I get warning before it dies or will I just loose that cylinder and the car will continue to run on 5 cylinders?

My first post:
https://www.audiforums.com/forum/b6-...-146686/page2/

 

The tapping might be dirty or clogged lifters or a lifter adjustment. Add a quart of automatic transmission fluid to your motor oil and warm your engine up. The high detergent content in the transmission oil may un clog the lifter, then change your oil and filter. Run your car for a few days and see if it clears up, if not try an additive if thats the problem and its not cured you'll need to replace your lifters or check the adjustment. If the lifter isn't fully extended the rocker hits the valve because theres not the proper gap and that is the tap you hear!!