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Northstar heart attack?


Logan

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30 minutes ago.....mile from the house.....car starts popping bad....at first I thought it was backfiring.....arrghhh no....

I think a plug broke.....just starting to look to see what happened.....

Lots of 'soot' around valve cover and ignition module near #1 cylinder (see picture).....the engine has some type of compression leak or something in the area...

http://images.andale.com/f2/115/106/376867...864_enginee.jpg

Guru.....you out there???

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Well, in the picture most of the surfaces are covered with a white dusting....notice around the edge of the ignition module.....major fumes were being produced...

This was pretty much a sudden failure.....good news it was 3/4 of a mile from the house. Crap...darn lucky I think.

The root cause...I think... is the #1 spark plug threads failed. I had been hearing some spis,spis,spis from the car lately...I guess a warning sign. I was thinking exhaust manifold gasket type issue.

Now the bad news....I was 3/4 of a mile from the house....thinking...ok....manifold gasket maybe coil pack. Ummmm....i'm pretty close it will be ok....

Got the rear ignition module off. #1 coil boot burnt beyond use....even the $400 coil module suffered burning. Plug loose in the plug cavity....so all along this 3/4 mile drive home.....fuel and spark were still working but now in the upper cylinder area.....basically outside of the engine.

The white dusting was from the rubber boot burning.

http://images.andale.com/f2/115/106/376867...305_engine2.jpg

Spark plug threads were gone in the head.

Spark plug was loose in the plug/ head pocket.

The coil boot shows evidence of the plug suddenly being forced into it.

The coil module had severe burning damage.

The spark plug electorde is still missing. We spent several hours trying to verify no debris were inside the cylinder.

The top spark plug 'screw' on electrode is also missing.

Trying a in car spark plug repair kit for the bad threads. Hope it holds....

Logan

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To have the problem happen here....a mile from home...is darn lucky. I could have been coming back from Michigan or something at 2am...

I am a little suspect of the plug repair kit.. but seems to be holding...

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Logan,

If you are looking for a new or used coilpack or new ignition module - I have parts I was going to sell on ebay. I will sell a new ignition module with new coilpacks for well under 1/2 of the new price.

Let me know.

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To have the problem happen here....a mile from home...is darn lucky. I could have been coming back from Michigan or something at 2am...

I am a little suspect of the plug repair kit.. but seems to be holding...

FWIW, I used a repair kit on an outboard motor with an aluminum head. Was still going strong some years later when I sold the boat. I don't know what the compression ratio was compared to a NS, but the motor was run mostly flat out pulling skiers, so you may be good to go.

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I am a little suspect of the plug repair kit.. but seems to be holding...

I've seen an "insert" type repair done on an aluminum head. Similar to the head bolt repair on the Northstar.

I believe, like the head bolt repair, that it's a very reliable repair. Better than a Helicoil.

I'm not sure if it's a Timesert product.

Barry

2008 STS V8
2016 Colorado Z71
1970 Corvette LT-1 Coupe

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I think this is the reason that bbobynski says not to change the plugs before 100,000 miles is the fear is that this could happen, not that the Northstar is suseptible to it, aluminum engines are suseptible to it. I had a friend with a Subaru that had it happen.

We have had a few discussions here about breaking frozen plugs loose with an impact wrench to avoid grinding the threads loosening them.

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Logan,

Didn't you just buy that car relatively recently? What was the history on it? Where did you get it? Just curious as my suspicious nature is wondering if it wasn't previously known and unloaded.

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I've had the car a year and a half.

One issue with the spark plug repair.....turns out the repair part in this case has no shoulder.....and it is larger than the spark plug seat....so technically after tapping the hole for the new sleeve.....the spark plug could basically never stop turn while going in.

Tried NAPA this morning for the TimeSert version that has the shoulder....Napa never heard of TimeSert.....great....

So from my box of 'vehicle parts of my past' I found the perfect washer to use as a shoulder. Plus used a new double plat plug.

http://images.andale.com/f2/115/106/376867...6_sparkplug.jpg

The plug was put together just like this before installing...along with some red high temp loctite.

I guess what was strange was the failure mode. On a older Northstar the plug and boot would just fly out. But this one being the newer version coil on plug.....everthing is trapped and bolted down.

Oh yeah....my minor 'spis, spis, spis' leak sound is gone. So if you have a 2000 or newer version....take the sound very serious.

I know what the fail mode is like now. If it happens again....I would stop the car....try to figure out which cylinder blew....then disconnect that fuel injector to get it home.

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Any thoughts on why this occurred?

Could the plugs have been overtightened/undertightened? (how tight are the other plugs now?)

Did they appear to have anti-seize on them?

As for waiting 100-thousand miles, wouldn't this assure they'd really be stuck? :) (I've heard horror storries about stuck plugs in aluminum heads (mostly Japanese cars))

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  • 1 month later...

Hey Logan about that break light thing u do how much would it coast for shipping to prince edward island, Canada?

user posted image

Defending Northstar perf a qtr mile at a time!!!!

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Hey guys go to this website and check out page 2 its my car and yenkos car..... the firstage is just my car then u can see both of oursmy cardomain

user posted image

Defending Northstar perf a qtr mile at a time!!!!

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what are you talkin about m I called you m cause i didnt want to give your real name buddy. You dont have to not want tem to no we no eachother hey dont think im that much of an iddiott do you guys????

user posted image

Defending Northstar perf a qtr mile at a time!!!!

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My ex has a 94 cutlass with a 3.1 that would have the same plug come out from time to time since it was new. It has been recently that it was discovered that the threads were messed up in the head and supposedly would not hold the plug anymore. What has been done to correct this I do not know. She is my ex so it is not my job to fix her car.

Caddy_Grill.jpg2008 DTS
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Oh God! In addition to everything else, now I have to listen for spis, spis, spis. I don't suppose you recorded a sound bite so I'll know what to listen for.

When I first read your post, I thought, "For me, this would be a disaster; but I have confidence that Logan will be able to fix the problem without too much sweat. After all, he turned a Deville into a DTS including turning a column shift into a floor shift with console. What's a little plug problem to a guy like that?"

If somebody showed me which cylinder was the problem, I wouldn't know how to disconnect the injector. I'll just hope it doesn't happen to me - or, if it does, it will be under the extended warranty.

How many miles on your Deville cum DTS?

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