NP300s are renowned for leaking oil from the factory pipe that run from the top[ of their turbo charger towards the intercooler. The seals from factory are a very loose fitting blade type seal that does not take long from new to leak pretty badly. Changing the seal doesn't really help they just leak again
We have been making our Aluminium mandrel bent hot pipe since 2018, we use 2 right fitting Viton Fluro carbon o rings seals to ensure it doesn't leak. As a direct replacement for the factory pipe we include the earth strap and one of the location brackets.
We also supply a new Viton o ring seal for the opposite end as well when're the hot pipe connects to the factory rubber intercooler hose.
www.crgfab.com.au/product/hot-pipe-suits-all-twin-turbo-np300