Need to know what parts should be replaced when changing the timming belt on a 2001 toyota camery 4cyl

The rule I've seen is , when you replace a timing belt you should at least examine the tension pulley. Some cars, you should also replace the water pump, because of it's access being so difficult to reach.

Hi. Since you took the chance of opening the engine to replace the timing belt, you might replace the seals and gaskets for the head, cover, and crankcase, including the valve seals. in this way you will add brand new seals, minimizing or eliminating any leak problems. Also, try to use shur-tak spray. This one hold the gaskets in place while putting the engine back together and adds a protective layer to them as well. Ask for it at any parts store.