Glow plugs, inspecting
WARNING: This page is about a different car, the 1996 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.
Burnt electrodes in glow plugs are frequently caused by malfunctioning Fuel Injectors. Damage of this nature is not caused by malfunction of the glow plugs.
If inspection reveals glow plug damage as shown (-arrow-), replacing the glow plugs is not sufficient. The Fuel Injectors must also be tested for opening pressure and leakage. See FUEL INJECTORS, SERVICING .