2006 Aveo - Plugs Covered with Oil!

[OG-Lou]

On my 2008 Aveo, I had oil in the spark plug wells and replaced the valve cover gasket and installed new spark plugs at 50K miles.

What I didn't know at the time was the oil inside the spark plug wells allowed a carbon track to develop and let the electrical energy that creates the spark to travel down the inside of the spark plug boot and go to ground under acceleration when there is slightly more resistance for the spark to jump the gap at the center to ground electrode.

I measured the resistance of the spark plug wires and they were all within specifications. What I didn't or couldn't do was measure for external conducting paths to the base (body) od the spark plug boot.

If your engine develops a miss fire, suspect the spark plug wire boots on 2008 and older Aveos, 2009 and newer Aveos also have had defective spark plug boots that were part of a recall.

Take it from me, I replaced several good parts until my MIL light came on and the OBD2 scanner said I had a miss fire on #3 cylinder a year after the problem first started. Yes it took a year for the check engine light to come on.

When I took the newish spark plugs out after the MIL came on I saw a carbon track from the top of the spark plug ceramic body, all of the way to the steel body of the spark plug, where the electricity was traveling on the outside of the spark plug instead of jumping the gap and creating a spark to ignite the fuel and air mixture inside the cylinder.

Another spark plug was just beginning to make an external carbon track so that indicated a second spark plug wire boot had an internal path for the high voltage to go to ground.

I bought a set of spark plug wires for under $20 and replaced 2 spark plugs and now my engine runs great.

I haven't done it, but I did read some valve cover bolts bottom out before securing the valve cover completely. One guy rebuilding his engine put a thin washer under the hear of the bolts that hold the valve cover tightly to the cylinder head.