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

Northstar Headgasket/Cracked Block/Bolt Failure? Please let us know

294K views 546 replies 243 participants last post by  ihc70 
#1 ·
Here is the Definitive Northstar Headgasket Thread. Please choose your year of Cadillac and state if you have had a headgasket problem with your Seville or Eldorado and what mileage it occured at. If you have never had a problem please do not participate in the poll!
 
#431 ·
I dunno, Joe ........... but I try to stay neutral on the "Northstars are junk" wars. Over the years I have repaired blown head gaskets on everything from Ford flathead B-blocks to Chrysler hemi's (1950's) to MG's to Ferrari to Chevy 327's to Ford 289's to Jaguar DOHC 6's. NO engine is forever - some are for only a few days !
 
#436 ·
Joe, have you been tapping the block on these coarser threaded head bolt engines?

it is my understanding that all the failures in engines with the coarser threaded head bolts were due to the bolts not being tight to begin with and not from pulling out
that then causes the gasket to fail compounding the issue
 
#437 ·
From a mechanical standpoint I like fine threads on studs/head bolts. It allows for more precise torque application as opposed to an initial torque then degree sequence.

Coarse threads in aluminum are just fine for the "meat" of an insert or stud grab - then sneak up on proper torque with well-rolled fine threads on the stud/nut or the original fine threads on a head bolt into a large insert. Look at the threads in Norm's Inserts. Coarse outside, fine inside.
 
#444 ·
Re: Definitive Northstar Headgasket Thread

But only 8 people in the world know that - the rest never search for the answers to every Cadillac problem: They're already posted in the stickies in each forum threads header and in Discussions, Cadillac Tech Tips.:want:
 
#446 ·
Ok this is the second one I have had apart in the last two weeks. It appears to me that the head gaskets failed no aluminum pulled when removing the bolts 1st one was a 02 DTS with fine threads 2nd one is a 04 Deville with coarse threads, both failed #1 cylinder I will post pics once I go in

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fine tread vs coarse




 
#455 ·
the process may have changed but the materials used we not any better

i seem to recall an issue with the quality of the aluminum that the blocks were cast with being the root cause of a lot of the 1999-2002 block porosity issues

maybe a chinese issue? and nothstar blocks weren't the only aluminum product that got hit ...
 
#457 ·
Re: Definitive Northstar Headgasket Thread

My LD8 N* is not in a Cadillac, but in a 2005 Pontiac Bonneville GXP. I always seem to have Murphy's Law as a permanent part of my life where it comes to vehicles. Anyway, after a couple low coolant warnings and adding coolant to the right level, the warning returned. Couldn't see any obvious leaks under the hood so I brought it to a local Cadillac Dealer (Fitzgerald- Frederick,MD), they did some tests and said the head gaskets were bad. I thought that the HG problems had been ironed out by 2004 ? Not sure which way to go at this point, they (dealer) plan to do "time-sert" when I think I'd rather use "big-serts" or studs, don't seem to fail as much from what I've read. I am also wondering about a GM replacement engine or a reman. unit with better warranties than I'll get from the dealer insert/repair job. I never thought that this could happen to an engine with less than 32,000 miles on it ! Anyway, now there's an entry for 2005 in gasket failure poll, even though it's for a non- Cadillac car. I do think I see a low mileage used CTS in my future though ! :yup:
 
#458 ·
I thought that the HG problems had been ironed out by 2004 ?

that is true, but that doesn't mean that you won't have a HG failure (just like any other car could have a HG failure)

from what I understand
most of the newer design (coarse-threaded head bolt design) HG jobs we have seen were due to loose HG bolts
the rest were actually gasket failure first

still pretty uncommon for the 2005-2011 N* but it will happen from time to time (just like any other motor)

as for time-serts vs big-serts

i would be really surprised if any dealer was actually still using the original time-serts
(i don't think you can buy them anymore... and if you can i'm not sure why you would)
it is probably just their way of saying big-serts and not really caring to be specific about it since most people won't really know the difference
(often they themselves don't know the difference or that there was a change at all)
 
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