One problem related to engine oil leaking has been reported for the 2004 Infiniti G35. The most recently reported issues are listed below.
I had a low oil light and decided to change the oil and spark plugs. When I removed the spark plug I found oil pooling in the spark plug tube and saw an obvious leak in the valve cover seal. The oil level had reached 1cm above the connector in the boot. This can potentially cause an engine fire while driving. The valve covers contain bad spark plug tube seals. This allows a significant amount of oil to pool in the spark plug tube. When the oil reaches the spark plug boot it can ignite and cause engine fires at high speed.