Been awhile since I have posted here, my 03 Sunfire has been holding up just fine after wrecking my 01 Cavy. Problem I had today is with my brothers 01 Cavy with the 2.2 OHV engine. Last time he had a tune up he had me install bosch plugs against my advice(I have heard bad things about these plugs, and have seen one split in half while my friend was driving his truck, causing it to lose a cylinder). It ran great for maybe 30-40k.

Now, the car developed what sounded like a lifter tick, but upon closer inspection one of the plugs was not seated correctly in the head, allowing a little air to blow by when the cylinder came up for the compression stroke. So I replaced all the plugs and wires and here is what I found:

4. Upon taking cylinder four plug out, the one that had the air pushing through, I was unable to screw a new AC Delco plug back in (or the old on in). When you start the car it just blows the whole @!#$ plug out. The threads are stripped and the new plug just falls in.

3. Came out normally, worked just fine.

2. I had to use a @!#$ breaker bar to get this one out, thats how sealed it was. It stripped the threads on the old sparkplug, but the new sparkplug screwed in just fine.

1. Came out normally and worked just fine.

All of the cylinders work fine except the fourth. Now has anyone ever heard of this happening? Is it the bosch plugs to blame or poor installation the first time? Like I said before they worked flawlessly all this time up until 3 weeks ago. I find it hard to believe that the plug some how magically stripped the threads on an iron cylinder head. Any input on this situation would be greatly appeciated, but for now I think I will replace the head with a lower mileage one.

I had bosch platinum plugs installed in my 01 cavalier for about a year now, Nothing really has happened to them yet (knock on wood), I remember years ago they used to be good quality parts, I am guessing they are not as good any more. Ive heard a few people had problems with bosch products. My friend installed a New bosch starter in his 2000 cavalier, it only lasted 2 weeks, Not sure what the deal with that was. Ive noticed though with used cars some alum cyl heads dont last too long, When proper corrosion application solution isnt added to the spark plug threads usually cause the cyl heads to strip a way, Just like bolts come loose when no thread lock is used.

Hope things work out for you

Good Luck

Marc, you said, "I find it hard to believe that the plug some how magically stripped the threads on an iron cylinder head."

I wish these engines did have iron cylinder heads, but, they're aluminum.

And, spark plugs tend to weld themselves.

Hope you have a heli coil expert that can re-thread.

Let us know how it turns out.

Well if they are aluminum, I can see them striping easier. But I mean, have any of you guys ever heard of this happening? I am not an expert mechanic or anything, but I have been around cars for a while, and have never heard of this happening. It sounds like a highly unusual problem to have.

On the repair side though, how quickly does it take to get the cylinder head off?

You don't HAVE to remove the head...

From Popular Mechanics --

Heli-Coils are a perfectly acceptable, inexpensive, long-term solution to stripped spark plug threads. Any good mechanic should be able to install them, and probably has the correct tap, installation tool and experience, as this is not an uncommon problem.

The repair procedure involves tapping new, larger threads into the head with the correct tap. It’s important not to drop metal shavings into the cylinder, so I use grease on the threads to catch any. Then the Heli-Coil is installed onto its installation tool. A Heli-Coil is basically a stainless steel spring made of square-section wire that is wound to the same pitch and diameter as the threads on the spark plug or bolt. There’s a small, prescored tang on the inboard end of the Heli-Coil that mates with a groove on the installation tool.

The tool, with Heli-Coil, is threaded into the freshly tapped hole. When the tool is backed out, the Heli-Coil remains. Needle-nose pliers are used to snap off the tang and remove it from the engine. Now you can just thread the spark plug into the new threads, and drive.

It sounds easy, but I don’t recommend trying this yourself. There’s a knack to it. There are also a number of other thread-repair inserts on the market, of varying types, and almost all of them work fine, but Heli-Coils are the simplest.

In the prior post it mentions using grease to catch metal shavings

that get into the cylinders when tapping for new spark plug threads....


I believe the best way is to suck out the cylinders with a shop vac

equipped with a narrow nozzle....

Heli-Coil FTW! Stripped a plug on my old '94 Sunbird. Heli-coiled it and it ran perfectly....until it got hit and totalled.



I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26

Thanks for the advice guys, I went to autozone and bought a helicoil and now it works fine. And to think I was about to change the whole head...