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Allante 1989 export running on LPG
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Discussion Starter #1
I was wondering if with the Northstar head-gasket problems if it is always the head bolts/stripped threads. I would like to hear from someone who has worked on a few of these, when you start to remove the head bolts do you find one of them completely lose?
I did read that the gaskets can sometime just deteriorate.
 

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White Diamond '03 DHS (with DTS floor shift)
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This is the chicken or the egg question, which went first. Either way, at least one thread will be compromised.
 

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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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Unfortunately, not all threads will hold. If that were the case the head gasket will remained sealed to the block for the most part.

A neglected cooling system is a set up for failure in these vehicles.

The first formulation or early formulations of dexcool didn't like the materials used in head gaskets or intake gaskets on various Gm motors.

Not to say there weren't corners probably cut in design either, but there was definitely a chemical / material issue going on.

The Northstars open deck design on earlier engines "may" have been a contributing factor on head gasket issues to some degree, but later design blocks are designed a little different and use a multi layered steel head gasket, that in my opinion should have been used from the beginning of the motors inception.

It is a very good power plant when you get the concerns handled, not very user friendly.

Yet, the few that do know how to work on them will get them to run correctly and most importantly stay together.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Chicken or the egg .............. ANY engine in ANY car can have a head gasket failure. In the Northstar the block metallurgy and bolt thread size/pitch was changed several times because apparently most gasket failures were due to bolt thread problems BUT some were also due to gasket failure itself, primarily the stainless steel fire ring against the edge of the iron cylinder liner. I suspect the open deck design was contributory.

Take a hard look at MLS steel head gaskets. Not inexpensive, but ....................

Head bolts - removal - some crack like a rifle shot, some twist out like they were in peanut butter, and some are just plain pulled loose. There are so many good ideas, pictures, conjecture, hearsay, rumor, witchcraft stories in the sticky threads on this forum main page that you'll have a LONG read ahead of you.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,261 Posts
I was wondering if with the Northstar head-gasket problems if it is always the head bolts/stripped threads. I would like to hear from someone who has worked on a few of these, when you start to remove the head bolts do you find one of them completely lose?
I did read that the gaskets can sometime just deteriorate.
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I was wondering if with the Northstar head-gasket problems
if it iss
alway the head bolts/stripped threads.

ALWAYS? - NO - there is NEVER an ALWAYS -

keep in mind that the Northstar head gasket failure rate is/was WAY overblown -
but I would break it down this way -

the vast majority - through 1999 - yes
the majority - 2000 through mid 2004 -
2005 and newer - very rarely -
 

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2001 GMC SLT, Malibu LTZ, 99 STS studded with NP
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499 Posts
=============================
I was wondering if with the Northstar head-gasket problems
if it iss alway the head bolts/stripped threads.

ALWAYS? - NO - there is NEVER an ALWAYS -

keep in mind that the Northstar head gasket failure rate is/was WAY overblown -
but I would break it down this way -

the vast majority - through 1999 - yes
the majority - 2000 through mid 2004 -
2005 and newer - very rarely -
I have seen my share of 2000-2005. I have done more of them than 1999 and earlier. Almost every one it was cylinder #1 dosnt matter what year. The 99 and earlier almost always pull treads on removal. The newer ones I don't think I have ever had treads on the bolt. This is just my experience
 

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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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Cylinder number 1 has an issue going on and I still haven't figured it out.....I've done a few and since the first one I scrutinized, cylinder 1 has an issue......
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Take a long, hard look at this picture of a right bank head gasket seated on the block. Notice the graduated size of the lower coolant transfer holes - increasing in size from #7 forward to #1 - and the front curved coolant hole at #1 ?

Cylinder #1 is the farthest, flow-wise, from the water pump. Is it possible that there's some sort of hot spot/cold spot near #1 ???
 

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2001 GMC SLT, Malibu LTZ, 99 STS studded with NP
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that's what I think too sub. I have had 3 that put coolant in the oil one was a 99 aurora a 98 deville and a 05 deville. Two with bad heads from cly. #1 with carbon burn from people that keep trying band aid fixes. I have seen all the snake oils in them. But they all fail any one that thinks a fluid that turns into s**t is going to hold compression is crazy. the oldest I have fixed is a 96 newest is a 05
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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The pic also shows, in stark detail, that about the ONLY cylinder seal in the siamesed and #1 front cylinder liner areas is the stainless steel fire rings.

Compare a block with no gasket sitting on it - and the posted picture. It's pretty obvious that the gasket flow and steam holes are used to control coolant flow from the block, up to the heads, and back to the intake side of the water crossover. The positioning of the curved coolant flow holes insures good flow around the exhaust port/exhaust valve seat areas; less flow is needed near the already-cool intake areas.

Here's some comparison homework .............

https://www.google.com/search?q=cadillac+2006+dts+ignition+key&ie=utf-8&oe=utf-8

https://www.google.com/search?q=cadillac+northstar+head+gasket+images&tbm=isch&tbo=u&source=univ&sa=X&ved=0CDkQ7AlqFQoTCMCxi-mtj8YCFcGPDQod9akAVQ&biw=1366&bih=601
 
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