Coolant hoses include the upper and lower radiator hoses plus heater hoses. Some cars include a bypass hose. Hoses provide a flexible connection for coolant flow between the engine, radiator, engine and heating block. Tiny cracks can form from the inside that can eventually lead to a burst hose and overheated engine.
Timing belts. The timing belt is also sometimes called a camshaft drive belt or a Gilmer belt. It is a notched belt, made of rubber, that enables the crankshaft to turn the camshaft, and opens and closes the engine valves synchronously with the pistons. In late model vehicles, the timing belt has essentially replaced the metal timing chain.