An Injection Seal (often referred to as a fuel injector seal / injector O-ring gasket) in Audi vehicles is a precision-engineered seal placed at the interface between the fuel injector and the intake manifold or cylinder head. Its main purpose is to prevent fuel leaks, air ingress, and loss of compression where the injector sits in the engine. Made from high-quality heat-resistant rubber or elastomer material, the injection seal must withstand high pressure, temperature fluctuations, and exposure to fuel and engine oils. Over time, these seals can harden, crack, or become brittle, leading to injector leaks, poor idling, rough running, or increased fuel consumption. Replacing injector seals with correct OEM-specified parts ensures proper sealing, efficient fuel delivery, and optimal engine performance in Audi vehicles.