Troubleshooting Oil on Spark Plugs Expert Insights

Oil in spark plug wells is almost always caused by an old perished gasket. After a number of years the gasket shrinks due to constant heating ... That's usually a sign that the spark plug tube seal is leaking. Likely need to get a valve cover gasket kit, remove and replace the valve cover ... The valve cover has a seal that goes around each spark plug tube. If that seal leaks you will get a slight amount of oil on top of the spark ... This is because the o-rings around the spark plug cavity are leaking. It's a combination of these o-rings and the valve cover gasket that keeps ... It's not a big deal but you do need to identify and correct the cause of the leak (needs plug tube seals and quite possibly the valve cover gaskets). Oil on the plugs isn't from the valve cover gaskets in our case, it is from the spark plug seals which are built-in to the valve cover itself and cannot be ... If there is any question, the spark plug tube seal is offered by GM - Part Number 12607600. "Window shopping" for a Silverado isn't all that bad ... It's the spark plug o-rings. Just take off the valve cover and replace them. There are 4 total and are included with the valve cover gasket set. When the tube seals on these engines leak, the entire well will fill with oil, and it will wick through the threads from the top down. All you need is a valve cover gasket set. You simply undo and take the valve cover off, give it a clean and pop the gasket out gently where the spark plugs go.