Noticed that my Polo (1997) 6n1 1.4 was leaking oil near the engine. Essentially engine oil would drip on outside to the oil pan and form a small poddle on the ground. After some time the problem area was narrowed down to the head gasket or the valve cover gasket. As of currently only the engine oil is leaking and not the coolant. Nor is there any white smoke from the exhaust.

Is there a sealer that works on external oil leaks from the head gasket or the valve cover gasket? Or are there any other product that can help with external oil leaks?