Part Type: Engine Coolant Reservoir Cap. 1999 Volkswagen Jetta Submodel: GL; Engine: 2.0L L4;EngineCode: AEG;. 1999 Volkswagen Jetta Submodel: GLS; Engine: 2.0L L4;EngineCode: AEG; EngineVIN: -;. 1999 Volkswagen Jetta Submodel: GLX; Engine: 2.8L V6;EngineCode: AAA;.