In turbocharged engines, the oil feed pipe (or line) is connected to the engine lubrication system. Its main function is to secure appropriate lubrication needed for the turbocharger unit and specifically, for its shaft.

If oil is not present at start-up and while the turbo is running, the bearings will fail. Running a turbo without oil for five seconds is as harmful as running an engine without oil for five minutes.

If the seals between the compressor and the engine become worn or cracked, the oil will leak into the exhaust system. As a result, the turbo has to work harder to increase air pressure. This problem is also known as over-speeding. Ultimately, it will reduce the efficiency and the boost delivered by the turbo.