There are two ways to tell if the timing belt has been replaced. One is obvious-you are looking at a service receipt showing the replacement.
Swimlane diagrams are used whenever you need to show activities, tasks, or process steps which are being performed by different actors/roles. You can use swimlanes to group activities in an activity diagram or process flow by any category what you need: by role, by system, by department, etc.
Once you've decided which process you want to improve, document each step using a Flowchart or a Swim Lane Diagram . These tools show the steps in the process visually. (Swim lane diagrams are slightly more complex than flowcharts, but they're great for processes that involve several people or groups.)