I'm on year 15 with my 07 Rainier with the 5.3 since I bought it. Just about 180k miles on it now. I've handed it down to my son who drives it back and forth from college. It's had a lifter tick on start up for at least a decade. Within the last year or so, the tick never goes away once it warms up like it used to and just ticks loudly the whole time you drive it. The engine still functions as it should. My other 5.3 I owned for many years, one day a lifter collapsed with no warning at all, no signs, no symptoms, no noise and that was the end of that car. This one just keep on going. I guess my question is how long can this continue? How has it lasted this long in the first place? My concern is failure on one of his long drives to school in the middle of nowhere. I'm gambling at this point but really can't get another car for him and it isn't worth paying for the tear down to replace the lifter.