This is a picture of an engine where the valve cover has been removed, so that the cam shaft can be seen. However, the most important part in the picture, is the exhaust manifold, and where the catalitic converter is fitted. This should warm up as quickly as possible and, therefore, is installed into the exhaust gas flow as early as possible. At the top, the screw-threading for the Lambda sensor is visible. On the right, next to the catalytic converter, is the oil filter and above left, next to the exhaust manofold, the filling-pipe for the coolant can be seen.