INSPECTION & ADJUSTMENT
All 4-cylinder Volkswagen engines use a toothed belt to drive the camshaft(s). This design is lightweight, and offers a low amount of parasitic drag on the crankshaft, which increases the output of the engine. Additionally, inspection and replacement of the belt is a relatively simple task, (as opposed to replacing a timing chain and sprockets) ensuring that the engine is operating at its peak efficiency.
The timing belt is a basic, yet critical engine component. If the belt were to break, the valvetrain can be seriously damaged. Frequent inspection, adjustment, and replacement of the timing belt and tensioning pulley is a must.
Volkswagen specifies a 15,000 mile (24,000 km) inspection/adjustment interval of the timing belt. For 1997-99 TDI engines, a 10,000 mile (16,000 km) inspection/adjustment interval is specified.
Volkswagen does not list a replacement interval for timing belts for gasoline engines, but do specify a 60,000 mile (96,000 km) interval for diesel engines. It is highly recommended on all 4-cylinder engines that the timing belt be replaced at this 60,000 mile interval.