During this past week I have been reading forums on the, yes, you guessed right, timing belt, valves, etc. GRRR!! While I was reading, I came across a post about the plugs that someone had used that made a HUGE difference on performance and mileage and I am unable to find that post again. Can anyone help me with this? Brand, style, PART #, etc..... Thanks alot!! Joe---

 

I don't know about the performance issue...but Hey! I was changing the plugs on my 07Aveo and pulled out the first plug... What the heck?

There was about a quarter-cup of engine oil in the well of the plug! Has anyone seen this before?

I cleaned the oil out as best I could and the other three cylinder plug-wells had oil in them too. What gives?

Car ran/runs fine, no other issues. Does not burn oil, does not misfire, does not do anything but give me dependable transport at 30mpg.

 

I don't think there any plugs that will give a significant improvement in gas mileage but from what I've read on other forums it is best to just stick with the OE which are the NGK's.

 

Oil in the spark plug wells probably means you need to replace the valve cover gasket.

 

Hmmm. Ok. There is no other evidence of oil anywhere near the valve cover. Lifting the plastic engine cover off the top revealed only a clean area. All the oil was in the well of the spark plugs, which are about 2" deep, with no oil on the sides of the wells. I am going to pull one of the plugs Wednesday and see if after running the car for 150miles will leave oil in there. Thanks for the thought.

 

Ok, so I checked the spark plug well today... no oil. There was a very light residue of oil near the opening of the well, but not enough to drip into the well itself. I am at a loss to explain where the oil came from.

?

 

Give it time. The valve cover gasket has O-shaped segments that seal around the spark plug wells. Whatever oil that seeps out through them has nowhere to go.

 

I just got a spark plug recall in the mail for my 2009 Aveo LT5
You might want to see if it applies to your Aveo.
Good Luck