This gasket seals the joint between the turbocharger and its mounting flange on the engine. It prevents exhaust gas and oil leaks at the connection point, maintaining the pressure differential required for proper turbocharger operation. A failed gasket produces a whistling noise, loss of boost pressure, and oil seepage. The gasket is manufactured to the same material thickness and crush profile as the original, ensuring the clamp load from the mounting hardware is correctly distributed across the sealing face. Replace the gasket whenever the turbocharger is removed for service; clean both sealing surfaces before installation.