INFINITI G35 valve cover oil leak affecting spark plug tubes due to non-replaceable o-ring gaskets on INFINITI G35

Submitted by dervish · Jun 23, 2025
Published by RepairPal

Problem overview

Some Infiniti G35 owners report experiencing oil leaks from the valve cover that affect the spark plug tubes due to non-replaceable o-ring gaskets. This issue arises because the spark plug o-rings are built into the valve cover, leading to oil leaking into the spark plug wells. In some cases, this leak necessitates the complete replacement of the valve covers, as the plug well seals cannot be serviced. Additionally, owners have noted that the valve covers are prone to bad spark plug tube seals, which can result in oil pooling in the spark plug tubes and potentially pose a risk of engine fires. It is advisable for owners to inspect the valve cover gaskets if there is any external oil leakage, as internal leaks into the spark plug tubes may also be present.

9 people reported this problem
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INFINITI G35 vehicles with this problem

Average mileage: 97,750 miles
(90,000 - 109,000)

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