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Thanks for the info.

I need to know what's a decent/avg price for head gasket replacement on an 02 DTS?

Is this something I should have done by a GM/Cadillac service center ONLY?

If I understood correctly the inserts aren't necessary if the block itself isn't damaged and the 2003 or later bolts are used? But if there block damage the inserts have to be used?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Inserts or studs are used regardless - the head gaskets fail due to cylinder block bolt hole thread failure, not the other way around.

A head gasket job at a Cadillac dealer will easily run $4,500 ++++.

Try to get in touch with either Jake at www.northstarperformance.com or Tim at www.carrollcustomcadillac.com or Norm at www.huhnsolutions.com and find out if there is/are shops in your area doing the work and using their head stud/insert (bulletproof) kits. Usually half the dealer pricing.

Go back and read Post #159 - plus as much of this thread as you can ........... it's all in here.
 

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1998 STS
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71 Posts
In looking at the 'solutions', huhnsolutions uses inserts, northstarperformance and carroll use studs with large threads for the block. Other than huhn giving you the option of studs or bolts, any reason to choose one or the other?
 

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White Diamond '03 DHS (with DTS floor shift)
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Not really. Either way will get the job done. Studs are far better if you are going to pull the heads again, but nobody ever plans on doing THAT twice.

P.S.
Timesert also offers the coarser thread pitch. That would be their Bigsert.
 

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2005 CTS/ 2008 DTS/ 2008 STS V8 N*/ 2011 CTS4 ALL W/D Pearl
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Could someone please direct me to the thread about rwd or awd Northstar head bolt issues compared to fwd Northstar head bolt issues. Thanks. Or please give you're opinion on the matter.
 

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97 ETC x2, 04 GXP, 04 STS x2, 97 ESC, 99 Deville, 05 SRX
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Not really. Either way will get the job done. Studs are far better if you are going to pull the heads again, but nobody ever plans on doing THAT twice.

P.S.
Timesert also offers the coarser thread pitch. That would be their Bigsert.
Not correct. The pitch remains at 1.5mm, unless you're using the M11x2.0 inserts, than the external thread pitch remains at 2.0mm.

Timesert has a patent on their inserts, that the external and internal threads are synchronized. You can't synchronize threads unless the same pitch is maintained externally and internally.

The coarser the threads, the less chance of thread failure again. That's why most inserts are considered a band-aid fix. Sometimes they hold, sometimes they don't.

M11x2.0 was an improvement. But it's far from the fix.

Nothing will beat a stud as far as accurate torque/clamp load distribution. Nothing will beat coarse threads in aluminum. Nobody want's something that is "almost as good as factory" or "might work". You want something that will not fail.

http://www.northstarperformance.com/sgstuds.php (patent pending).
 

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1998 STS
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Looks like my son is one of the 'lucky' ones, car is starting overheat, losing coolant, white smoke when cold, seems to go away as it warms up, (for now). It's an '98 STS, 136k on it. We've recently changed out the radiator, alternator, power steering pump, tires, now this. Trying to decide if it's worth going with a remanufactured engine, not sure who even has them that are done right, probably nearing $5,000 for the whole job, right? And he's at college, just great!

____________________________________________________________________________________________________

Read back through this thread. Many options already posted.
 

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Is their any insert that you can put in after shop has just done insert job head gasket failed in two days or is their any cheaper way to get kit for studs (wich my new mechanic believes is a better idea) any cheaper since Im only redoing the back head gasket that was leaking???? And if so can you install the studs and get heads on when the motors still in?? Since I just paid a guy 1400 when he didn't follow the procedure of my warranty CARS PROTECTION PLUS and my claim got denied AND was left with a car tore apart and a job that cost 1400 and a warranty company and a mechanic that screwed me over ..its been a nightmare and a expence I that has put me in debt so I need a good permenent cheaper stud solution...please anyone
 

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1998 STS
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Is their any insert that you can put in after shop has just done insert job head gasket failed in two days or is their any cheaper way to get kit for studs (wich my new mechanic believes is a better idea) any cheaper since Im only redoing the back head gasket that was leaking???? And if so can you install the studs and get heads on when the motors still in?? Since I just paid a guy 1400 when he didn't follow the procedure of my warranty CARS PROTECTION PLUS and my claim got denied AND was left with a car tore apart and a job that cost 1400 and a warranty company and a mechanic that screwed me over ..its been a nightmare and a expence I that has put me in debt so I need a good permenent cheaper stud solution...please anyone
If I understand you correctly, inserts were installed and then failed? Depending on the insert size, I'd think there might not be enough material left to drill, tap and install a stud. From what I've read, (after stepping into an ongoing 'conflict' between the two stud kit vendors, I did a lot of reading), studs require the engine to be removed on a N*, pretty common on most cars, I've installed studs on a couple of V8s, (no N*s). Sorry to hear about you're issues, sounds like you're getting hit big time, sucks.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Depending on the insert first used, you might be able to rebuild the engine using studs from a couple of suppliers discussed in several threads OR use Norm Huhn's NS300L inserts - www.huhnsolutions.com

The big question - determined by a GOOD Northstar mechanic - "Is there enough block metal left to allow the larger diameter stud threads or NS300L threads to have sufficient "bite" in the newly cut block threads ?"

IF you can use studs, the engine probably has to come out of the car - there is no way to rotate it forward far enough to allow the right (rear) head to slip down over the studs. Some have opined that it might be possible to land the head (with the engine in the car) and then screw in the studs - but that precludes the necessary use of the head alignment locator dowel pins.

"Cheaper" - Unfortunately, good machine work is NOT cheap - neither are good parts. When I stud a marine Olds 455 it adds about $450 to the final price (about $7,500).
 

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97 ETC x2, 04 GXP, 04 STS x2, 97 ESC, 99 Deville, 05 SRX
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Jim, it does work to stud the engine in the car. On some models easier than others. I've never done it; but my customers have done it and told me it was tight but it worked.

Personally it's just as easy to pull the engine. But for those who just cannot, it does work.
 

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^^^ yep - that's why I posted the cautions.

That method isn't something that the once-in-a-while shadetree mechanic should attempt. Too much room for error, both during the necessary hole drilling/tapping and the actual stud+head insertion.

........... and my back wouldn't let me do it now, anyway ........... :devil: (I could hang Evrett upside-down with a chain fall, though ......)
 

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........... and my back wouldn't let me do it now, anyway ........... :devil: (I could hang Evrett upside-down with a chain fall, though ......)

BAHAHAHAHAHA, i Dont think my back would be able to handle that.


P.S. Thanks for spelling my name right.
 

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I may have missed this if it was posted earlier in this thread, but I now have a 2002 Eldorado ESC. I have heard that you do not have to worry about the headgasket failures from 2002 up models. Is this correct?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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If head gasket worries is your thing, then you may worry about any car on earth.

As far as unofficial percentage data, read through the poll in the head gasket thread close to this sticky.
 

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Re: low mileage 99 SLS

This post copied from a recent discussion on "Should I buy a Northstar car" up in Seville. For information.

................. and, hidden away in the posts and threads is the discussion of when, why and how GM changed the cylinder block metallurgy (the actual alloy used for block casting) to cure nuisance weeps and porosity.

In those threads there are several pictures of earlier Northstar block head bolt holes with significant pock marks and ash deposits in the threaded areas - that would possibly weaken the thread integrity. As soon as a few thread spirals fail and the bolt begins to lose clamping pressure, you're sunk.

*There are misleading pictures (one is here), showing "perforated" head gaskets. It makes not one iota of difference if head gasket material is fluffy and eroded in the areas of water jacket on both sides of the gasket. When the bolts lose enough tension to allow gas past the stainless steel fire ring, then problems start.

Check out the Northstar block deck and head mating surfaces. A right significant part of the gasket material simply hangs down into the block deck opening around each cylinder liner. You could cut away the gasket material there and it would make no difference in sealing ability. Think about it.

https://www.google.com/search?q=gm+northstar+head+gasket+images&tbm=isch&tbo=u&source=univ&sa=X&ei=NsoOVYPjJ4n4gwSC2IKwBg&ved=0CDwQ7Ak&biw=1366&bih=620

*Look hard at the picture. The indicated holes in the gasket material are in the block water jacket area. No way that causes a leak into a cylinder. Look closely at the obvious compressed areas - left lower center. See any erosion there ?????? In the old days the oval hole at the right and the round holes at the top left were referred to as "steam holes". The stainless steel fire ring is not "eaten through", is it ?

(BTW - You're looking at the bottom side of the head gasket - the fluffy sections, with the indicated holes, simply hang down into the open deck cooling passages around the cylinder liners - see the curves ? look at a Northstar block.)

https://www.google.com/search?q=cadillac+northstar+engine+block+images&tbm=isch&tbo=u&source=univ&sa=X&ei=KCdfVbvMG8WegwSWz4CIDA&ved=0CDkQ7Ak&biw=1366&bih=601
 

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1997 Deville non-concours
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Re: low mileage 99 SLS

So here's a non-engineer, non-mechanic, untrained, mostly uneducated and uninformed dingbat's 2c worth of question:

Has anyone wondered if the head gaskets might be allowing coolant to wick through them and down into the bolt holes, even if the head bolts are clamping properly and the mating surfaces aren't warped? If this IS what's happening than the holes through the non-sealing areas above the water jackets would be a more direct route for the coolant to be penetrating into the headgasket material itself.

It might be worthwhile to document how many HG's on failed northstar motors have obvious routes for coolant to penetrate into the HG's themselves. If one were really demented, they might start slicing the failed head gaskets along their long axis and start looking to see if the things are being permeated by coolant, and if they are, in what way.

The bunching would, I suspect start breaking down the HG's and exposing multiple layers of it directly to the coolant. Of course the metal sealing ring around the combustion chambers should keep the coolant out, but as we know once the bolts start letting go, the cylinders are no longer sealed!

(Moderator edit: This "wicking" possibility is discussed elsewhere in this thread as well as others. Please go back to Post #1 and start reading.)
 

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Re: low mileage 99 SLS

This post copied from a recent discussion on "Should I buy a Northstar car" up in Seville. For information.

................. and, hidden away in the posts and threads is the discussion of when, why and how GM changed the cylinder block metallurgy (the actual alloy used for block casting) to cure nuisance weeps and porosity.

In those threads there are several pictures of earlier Northstar block head bolt holes with significant pock marks and ash deposits in the threaded areas - that would possibly weaken the thread integrity. As soon as a few thread spirals fail and the bolt begins to lose clamping pressure, you're sunk.

*There are misleading pictures (one is here), showing "perforated" head gaskets. It makes not one iota of difference if head gasket material is fluffy and eroded in the areas of water jacket on both sides of the gasket. When the bolts lose enough tension to allow gas past the stainless steel fire ring, then problems start.

Check out the Northstar block deck and head mating surfaces. A right significant part of the gasket material simply hangs down into the block deck opening around each cylinder liner. You could cut away the gasket material there and it would make no difference in sealing ability. Think about it.

https://www.google.com/search?q=gm+northstar+head+gasket+images&tbm=isch&tbo=u&source=univ&sa=X&ei=NsoOVYPjJ4n4gwSC2IKwBg&ved=0CDwQ7Ak&biw=1366&bih=620

*Look hard at the picture. The indicated holes in the gasket material are in the block water jacket area. No way that causes a leak into a cylinder. Look closely at the obvious compressed areas - left lower center. See any erosion there ?????? In the old days the oval hole at the right and the round holes at the top left were referred to as "steam holes". The stainless steel fire ring is not "eaten through", is it ?

(BTW - You're looking at the bottom side of the head gasket - the fluffy sections, with the indicated holes, simply hang down into the open deck cooling passages around the cylinder liners - see the curves ? look at a Northstar block.)

https://www.google.com/search?q=cadillac+northstar+engine+block+images&tbm=isch&tbo=u&source=univ&sa=X&ei=KCdfVbvMG8WegwSWz4CIDA&ved=0CDkQ7Ak&biw=1366&bih=601

Well this was an interesting development in my absence.

In what is now the OP here, I wasn't asking if the fire/cylinder sealing ring wouldn't seal per se because of the head gasket design.

I was simply asking the chicken and the egg question - what happens first? Does the headbolt get loose and THAN coolant runs down into the headbolt threads? Or does the coolant get down into the headbolt threads, degrade the metal, and THAN the headbolts loosen. Lack of sealing on the cylinder ring is simply what happens after (whichever of these two) happens.

Regarding this question and the headgasket, I was simply wondering "out loud" if the head gaskets were allowing coolant from the open deck to get through the gasket material and down the headbolts. Given how wet my head gaskets were it's obvious they are permeable by the sealant after they take enough abuse from the bunching-stretching we've all seen. That doesn't mean the water is working through the gasket material ... I was simply pointing out another route for investigation (coolant through gasket material to the headbolts).

Absolutely not surprised to see this discussion ongoing here :)

EDIT: or frankly this could be more alice in wonderland and the thread bolts could be mechanically failing or the metals they used could be failing.
 
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