Your PCV system is a "sealed" system. It draws filtered air from before the throttle plate (or from the filter housing for you carb'd) through this hose into the crankcase and then through your PCV valve and into the intake. This hose from your valve cover (right behind the oil cap) to throttle body (or air filter housing to v/c for you carb'd guys) is brittle and not sealing right. It’s 20+ years old. You’ve already noticed the cracks on it. Don’t skimp. C’mon. You don’t want a vacuum leak.