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Select one if you have had a problem with the headgasket the Northstar V8:


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1997 ETC
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1 Posts
Re: Northstar head gasket failures

I have a beautifully kept classy red 1997 Cadillac Eldorado ETC with just 73,000+ miles on it now sitting in a bay at a local dealership with a blown headgasket. I'm sick. Thousands of dollars of new parts on this car just in the last year. It's been my pride and joy since 1998, but sadly I think it's time to let 'er go.
 

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1999 DeVille
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20 Posts
Hi all:

This continuing thread looks like a good place to post my head gasket problem and repair, which has been recently completed. I have a 99 Deville that has been in the
family since new. At 165,000 the aft head started leaking. We decided to have it fixed. The problem was where and whom. Forget the dealer, I wanted someone with
specific knowledge, experience, and affordable price. After much searching I decided on a place in Youngstown, Ohio, by the name of Davis auto repair, AKA The Cadillac Doctor. The main reason was that I was driving from St. Louis to Cleveland for Christmas, and his place is close to where my family lives.

I contacted him in November and he said he could take care of it. We drove up there, stopping every now and then to add coolant. Thank goodness for the cold temps
on the drive up there. Dale Davis is one of the nicest guys I have ever met. He is also very trusting. He had me drop off the car at his house on a Sunday, so they could start on it early on Monday. I decided to get a rebuilt engine at the last minute. Dale didn't have any rebuilts available, so he rebuilt mine. Dale and his guys worked overtime the week of Christmas to rebuild my engine and have me and my family on our way the next weekend.

For anyone considering the headgasket repair or a rebuilt, I highly recommend Dale, It will be worth your drive!

We look forward to many more miles in the Caddy.

N3870V
 

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1973 Cadillac Hearse, 2002 Cadillac DHS
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288 Posts
I'll add mine here and fill out the poll too. I have a pristine 2002 DHS purchased used. Caddy entered the early stages of HG failure January 2014 at 88K. Car is fixed and back home as of a week ago running like new. Motor was removed, re gasketed top to bottom, new timing set, rebuilt the heads and all 20 bolt holes were repaired using NS300L's. An engine machine shop specializing in Northstars did mine. No more nuisance oil leaks/smells either. Love my Caddy!
 

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1998 Deville Base
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88 Posts
I already answered the poll for my 1998 Deville (which blew HGs around 94k miles), but I'd like to add that my dad's 2004 deville also blew head gaskets! This is very rare and it shocked both me and him, and as the poll shows 0 people have had a 2004 HG issues. Granted his car is around 188k but still. Very surpring for a N* made during that time.
 

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04 DHS
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279 Posts
I already answered the poll for my 1998 Deville (which blew HGs around 94k miles), but I'd like to add that my dad's 2004 deville also blew head gaskets! This is very rare and it shocked both me and him, and as the poll shows 0 people have had a 2004 HG issues. Granted his car is around 188k but still. Very surpring for a N* made during that time.
Owww, the final category has fallen:suspense:


J.R.
 

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Devilles: 04 Base,01 base,01 DHS,92 (parents)
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211 Posts
Another one bites the dust.

2001 deville base model silver with black top
143000 ish mileage.
Head gasket/overheating
 

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2005 Escalade 6.0 AWD, 2004 SLS, 2005 Bonnie GXP
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237 Posts
2004 Bonnie GXP, blown headgasket 125k
2005 Bonnie GXP, blown headgasket 126k
2005 Deville, blown headgasket 100k
 

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1999 White Diamond ETC
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2,538 Posts
Wow @ Bonnie GXP. When I saw this poll I switched to conventional (silicated) green coolant. I'm at 112k with a 1999. Silicates coat the felt graphite gasket whereas dexcool doesn't. Not sure if it is relevant or not but seeing the escalation of cases was 1997 I had nothing to lose
So far so good. (Knock on wood)
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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26,323 Posts
DEX was introduced in '96, not '97. There is absolutely NO relationship between DEX-COOL and HG issues. If DEX was a factor, every GM vehicle produced from 1996 forward would have HG issues, and GM probably wouldn't still be using it...
 

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1999 White Diamond ETC
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2,538 Posts
MoistCabbage said:
DEX was introduced in '96, not '97. There is absolutely NO relationship between DEX-COOL and HG issues. If DEX was a factor, every GM vehicle produced from 1996 forward would have HG issues, and GM probably wouldn't still be using it...
I believe DEX-Cool was introduced in mid 1996 catching the tail end of 1996 production and mostly early 1997s.

Inorganic oxides like silicates in conventional green coolant work by forming a protective coat that actually coat the metals preventing corrosion. Because these inhibitor systems are depleted by forming a protective layer, conventional green coolants need to be changed every two years. (The color has nothing to do with it)

Dexcool is different. It is an OAT coolant.

MoistCabbage said:
There is absolutely NO relationship between DEX-COOL and HG issues. If DEX was a factor, every GM vehicle produced from 1996 forward would have HG issues, and GM probably wouldn't still be using it...
You cannot prove anything you said about dex being a factor either way. Not in a scientific way, certainly not prove "absolutely NO relationship." (Seat of the pants, however; you could argue your beliefs all day long if anyone wants to listen.)

The open deck design of the Northstar with the water jacket creating a coolant island around the siamesed cylinders is unusual and probably the weakness. The head gasket remains soaked by coolant and the gasket integrity usually looks bad on failed HGs. There has been mention of bunching up of the gasket in some instances.

The factors: old school felt graphite gaskets (vs chemically treated Multilayer Steel in similar modern designs), new organic coolant that doesn't coat the old material but instead reacts with metals when exposed to corrosion. No question that organic additive technology coolants are good--they're used extensively now.

What is the harm in using conventional green? none. So no need to make a stink.

If you refer to the poll numbers--how do you explain them? The engine had changes in 1996 but none major in 1997.
 

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1993 Sedan Deville; 1997 Deville D'Elegance; 2010 DTS
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112 Posts
This is not a head gasket problem. It is a head bolt problem. The head pulls away from the block because the bolts pull out of the head due to a design flaw. The type of coolant you use, and maybe to some significant degree the type of driving you do, is going to have little impact on whether this problem arises for you. It's a product defect, not the sole consequence of bad maintenance or poor operation habits. If the person doing your head gasket job takes the time to research the problem and either redos the bolt sleeves as many people suggest or put in a different kind of stud as a couple companies are touting, then your HG issues will be over for quite some time. If your repair shop is simply pulling the heads and slapping on a new gasket, then there is a high percentage chance that you'll be back in the shop with the same problem.

Nick in Palm Springs
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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26,323 Posts
There is no harm in using green coolant. But I ask again, why hasn't every GM vehicle had HG/cooling system issues since DEX was introduced? They ALL use DEX. ABS why doesn't every Northstar vehicle running DEX have HG issues? ----------
mtflight said:
you can't definitively prove it other than have a lot of strong feelings because you've heard this argument before and made up your mind already based on what you believe
Which is exact why you switched to green.

Can you find one instance, where any cooling system component irHGissue was traced to DEX being the cause?
 

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1999 White Diamond ETC
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2,538 Posts
MoistCabbage said:
There is no harm in using green coolant. But I ask again, why hasn't every GM vehicle had HG/cooling system issues since DEX was introduced? They ALL use DEX. ABS why doesn't every Northstar vehicle running DEX have HG issues? ---------- Which is exact why you switched to green. Can you find one instance, where any cooling system component irHGissue was traced to DEX being the cause?
Hypothesis: The issue is a gasket breach somewhere around the open deck water jacket (usually a pin hole but some have noted the gasket looks bad in these open areas). clearly the gasket below isn't healthy. It has signs of corrosion (iron oxide) in the passages as well as bunching or cracking in the waterjacket area. Some claim this is not a problem because this is not where the headgasket failure occurs, but rather in the fire ring mate area... this is true but we can see here that the organic corrosion inhibitors didn't quite do their job and something has to structurally hold the fire rings in place. It looks like the siamesed cylinders in the center become an island and the integrity of the gasket itself is compromised in teh same area... moving around, bunching up. This is inherently an "open deck" feature. In order to keep combustion gasses from escaping the chamber and breaching into the water coolant area--the gasket must be strong and not weakened.



Why aren't all engines affected? Other current engines of that time used don't have these open deck designs--they had steam holes or smaller contact areas. The ones with open deck designs now use chemically resistant multilayer steel gaskets that don't deteriorate the same way. So the problem largely doesn't exist anymore.

This gasket deterioration occurred over time slowly enough to make it difficult to trace. I am hedging my hypothesis on the pre 1997 poll history with an innocent solution based on the chemical properties of silicated green coolant.

I am not saying dexcool caused the HG failures as much as I'm saying that silicates, from a chemical standpoint, seem to protect the felt graphite gasket better. Other open deck designs like Subaru also see higher HG issues. It's not a northstar only issue--it is an open deck issue.

Edit SUMMARY: dexcool doesn't eat or deteriorate gaskets (unless they have silicone rubber or Nylon 6,6 which was the topic of a class action lawsuit in the last decade). Dex-cool isn't at fault for ruining head gaskets. From the evidence however, it doesn't seem to protect the northstar hg from corrosion as well as silicates did back when they were standard . Changing the coolant every 2 years max was a necessity and an inconvenience.

Silicates, by creating a physical coating on the gasket, may protect the gasket integrity better in a design that relies on this gasket heavily, it could be a factor (as well as the open deck design, and possibly casting porosities as well which are nil in this argument).

If the gasket goes the coolant damages the bolt threads and it makes it tough to determine if the chicken or the egg came first.

Dexcool has an excellent track record--works well in aluminum engines without coating them with silicates, has possibly been reformulated, and was discovered to erode nylon 6,6 a common material after the fact.
 

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2001 GMC SLT, Malibu LTZ, 99 STS studded with NP
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499 Posts
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[/COLOR]I did a 98 Aurora about a month ago with overheat and cream sickle colored oil . Cylinder 5 had a crack in it. The owner bought the car new he decided to scrap the car. Right now I have a 96 Deville in for head gaskets and mid case reseal. This one has 96,000 miles on it. Cylinder head has a really bad nick or burn mark in it really deep also cream sickle oil. I am waiting for a used engine from Northstar Performance that has been checked out for worn parts and studded and resealed. these are my first bad apples I have repaired many now. this has me a little bummed out.
 

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2001 GMC SLT, Malibu LTZ, 99 STS studded with NP
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499 Posts
just finished a 99 etc with 99,000 on it. The exhaust cams and lifters were the worst I have seen. Got two regrinds from Northstar Performance and 16 lifters from rock auto. This was by far the cleanest 99 I have seen. Next is a 2005 deville with 146,000 on it
 

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2002 Deville and 2009 DTS
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491 Posts
Re: Definitive Northstar Headgasket Thread

2002 Cadillac Deville. There was a problem when the car was at 20,000 miles and they had to remove the head blocks. Not a good idea with aluminum engines.
Fast forward 5 years and BAD head gasket leak, and I had to have the engine replaced!
 

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90 Coupe, 94 KD, 98 KS, 99KD
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3 Posts
Just joined, but I read the title, and I'm commenting based on the very first post/question as asked.

I'm sure many of my observations have been noted by others (and this thread is really long), but I'm simply trying to be helpful to those unfamiliar with, or that don't know or wonder why/where/what is going on with these engines. Again, not stepping on toes, just commenting based on my experience.

As a dealership Shop Foreman, I've been involved in over 200 NorthStar head gasket/block repairs since the late 90's-2011 (dealership), and at my independent shop we did over 40 this yr alone!

Head gasket failure in NorthStars' is rust related. Period.
...and, yes, 99.9% are DexCool engines.

That being said...IF you had head gasket failure on a 1993-95 NorthStar, it either had (1) exceptionally bad maintainence routines',(2) dexcool introduced at some point in its life (which dealerships were advised to use in ALL heater core failures in the late 90's!), (3) previous engine disassembly and repair early in life (wristpins were common failures), or (4) SEVERE overheating at some point. Most of them that are overheated that badly (to "blow" a h/g) will have a cracked aluminum liner casing as evidence. Early engines also dealt with block porosity, but not super common. Most of them broke bolt holes externally, seeped water, or cracked around rear main. I'm sure a few pulled bolts from porosity, but I never personally experienced it. Many more had wrist pin failures, which I suspect early service repairs may have resulted in thread pull later in life.

They fixed the porosity problem about the same time as oil consumption became an issue...but that's another story...

Funny thing.

1993-95 with head gasket leaks seem to push water ONLY on very long hwy drives...because the average cylinder pressure is higher at 2000rpm than low/varying engine speeds, I theorize.

96 up loose water over a set amount of time...which gets closer and closer and closer as the rotting continues to worsen. Also, most, if not all, will have an engine miss when cold, once the rusting has progressed sufficiently, early engines don't seem to have the same symptoms cold.

All of them seem to have something I call

"The Rule of 3's"

Water pump, pump housing seals, radiator...then HGs
Radiator, coolant reservoir, water pump...then HGs
Heater core, radiator, water pump...then HGs.
X, Y, Z...then HGs. Everyone seems to have already had a leaky X, Y, Z, then they finally figure out the pressurization of the cooling system is simply making things leak from abnormal pressures during warm-up. Think about it if you've had HG failure. You probably did 3 things before you diagnosed the HG failure...

These failures are TIME related...NOT mileage!
The bolt threads pull because they have to be removed. Many times we find dexcool in the bolt holes, usually those pull worse. No gasket failure, no coolant in threads, no bolt removal, no thread repairs...ect. We've ALREADY done several 04's, 05's, and (2) 06/07 DTS's...one of which had only 53K.
So no, the pitch of the threads had absolutely nothing to do with it.

I'm sure some of the experts here will disagree, but I can post up, literally, pics of 100+ head gaskets that I keep to show customers.

I call it the "Wall of Shame".

Just plain rust bubbles...from DexCool coolant.
We use only conventional green coolant and advise the customer what to use and why.

DexCool is not allowed in my shop.
Period.
 

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1999 White Diamond ETC
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2,538 Posts
CadillacMaster, like yourself I look at the numbers and I theorize that it isn't DexCool that damages anything, rather that the organic acid technology coolant does not protect the gasket as well as the silicate coating technlology does on conventional green coolant. Thank you for posting this :)
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Begs the question - DEX-COOL or not - in an aluminum engine that uses head gaskets with stainless steel fire rings, what "rusts" to cause head gasket failure ? Not the gasket itself - OEM is graphite/carbon/fiber material. Yes, parts of the gaskets erode - the parts hanging loose over the open deck water passages. Normal in any engine. But somehow exhaust gas begins to make its way past the fire ring(s) and coolant weeps begin - something has loosened the head bolt clamping force.

See what the Cadillac Technical Archive - written by a GM Northstar powertrain engineer - says concerning DEX-COOL. Top black bar ^^^.

So every engine serviced with DEX-COOL or a same technology coolant will "blow a head gasket" ??? Do you really believe that ? Don't get me wrong - good ol' low silicate Green Goddess is great coolant and, when properly maintained, it provides long service and good engine cooling system protection ........ just like DEX-COOL.

.................. essentially ALL "green" coolant is now "low silicate" technology - to prevent excessive wear on water pump seals. Read the labels.
 
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