One problem related to gas recirculation valve (egr valve) has been reported for the 1999 Volkswagen Beetle. The most recently reported issues are listed below.
The water pump has a part that goes into the engine; it's made of plastic and called an impeller. It is part of the water pump. The plastic impeller disintegrated, causing the engine to overheat. The engine light on the dashboard came on just minutes before the engine ceased up. Other than that, there was no warning that the engine was running hot. Normally when a water pump goes out, the water leaks out. In this case, the water remained in and did not circulate. Repairer has asked owner for money to replace the engine entirely. Vw will not stand by its manufacturer's warranty, which the owner has. The plastic impeller is a common design defect which vw knows has a short life, but they keep designing their vws with a plastic impeller!.