I have an odd issue. My 07 hhr Lt has twice now had a spark plug blown out or ejected from the cylinder like a bullet. The weird thing is that the threading is intact so I can just screw in a new one but I have to replace the coil because it gets blown apart from the force. I had a camshaft position sensor error once before when my starter went out, I initially figured the error code was from the starter but now I wonder if it is actually going bad. Are the two things related? What would cause the spark plug to get shot out like that?

 

Question time....

What brand of plugs are you using? (The only plug for non-turbo Ecotecs is an AC Delco 41-103 Iridium plug)

Are you positive that the threads are undamaged, have they been examined using a borescope, and are the plugs unusually loose when you thread them in?

A failing starter normally wouldn't trigger a code, but a weak battery can cause all sorts of havoc.

And to answer your question directly, when an engine fires out a plug it's almost always bad threads or the wrong plugs being used.

 

And no correct spark plug "blows" out without damaging threads if it is torqued correctly on the install. If they have been installed with lubrication on the threads, even if torqued properly, it is conceivable that they will un-thread themselves and 'fall out" with force.

bigwillyg - if you mention that you had codes, you really need to detail what the actual codes were - else it's a guessing game. :)

 

I have used thread anti-seize on my plugs never had one blow out! never had one back out, there must be something to do with the threads in the head!

 

The threads are obviously stripped out, or you somehow have the wrong sized spark plug? (if thats even possible) if the spark plugs are torqued to specs, then they would never come out...I mean most people have trouble loosening (because they can break)when it comes to tune up time...

 

yeah, you all make valid points. I think this car is hosed. The second sparkplug/ignition coil that I replaced just had the same thing happen again but not as catastrophic. this time the threading wont even grab. I think I may have to give on it.

 

Helicoils?

 

Replacement head.

 

Used or a new head or have a competent machine shop install the Helicoils

 

A buddy at work used to work as agm service tech and has favors he can pull. He said he will try to get someone to do a thread repair on it.