Cracked engine block on 2000 Cadillacs

[edb150]

Texas Jim, my threads wer meant to be helpfull but were merged with the other threads so they appear negative.I was hoping to bring this info to light but it became an issue with some members and some what of an argument. I am indeed helping the Cadillac community by putting these wonderful cars back on the road. I work 12-14 hrs aday so my time here is limited. I mainly said i would keep everyone updated and am doing so.If you read the threads you will understand my point .I am Joe {edb150}.. and not 2112. i dont believe I knocked the northstar at any point. The info I brought here was to enlighten people to what I have found but it was brushed off as bad luck? And to add even more sadness to all this I now have a fifth broken block in my shop. I wish it were a bad dream but indeed its not.I am completely dumbfounded by it all.

[BodybyFisher]

Lets get something straight, it was 'brushed off' as 'bad luck' because while we have been doing this for 10 years and have thousands of members we had NEVER EVER heard of blocks cracking.........

[JohnnyG]

I would agree to close this thread Jim, but watching it for so long has me intigued. I would certainly like to know what exactly is causing these blocks to crack simply because I own a 2008 model. Assuredly it is a moot point since the Northstar is no longer in production, but there are a lot of owners out there that would SERIOUSLY like to know if there is an easy way to prevent this issue.

Now let's get into the wayback machine once again. Many years ago,(6?, 7?) I brought up the issue to bbob that carbon build up in the combustion chambers may contribute to headbolt thread pulling. I was assured at that time that that possibility was investigated by GM and no amount of testing indicated carbon buildup to be a contributory factor. This was when I owned my 1999 STS. Shortly thereafter, in 2000, there was a block redesign that was aimed at reducing block porosity issues, and just for kicks, the headbolts were drilled a little deeper too.

Now looking at the pictures, my first impression was that these blocks were frozen. But this is not a classic freeze burst type pattern, which typically blows out a chunk or section of the water jacket, complete with "hinging" of the blown out section. The forces involved in a freeze are in an outward thrust pattern (I've seen it on my boat block when the previous owner didn't drain it for winter). HOWEVER, these pictures do not indicate outward thrust or hinging of the metal away from the water jacket, and no bulging of the metal.

I think these blocks are cracking from excessive upward thrust created by the heads, acting directly on the external block material which is the weakest point now that the headbolts are not. I also would like to know what exactly is causing this excessive upward thrust. Before the head bolt threads were strengthened, I am going to assume that they would simply pull, now it looks like the block material is not up to the task and is cracking. The questions that I would like to ask is exactly how are these cars being driven? Are they driven gently, or in such a way that may lead to carbon buildup in the combustion chambers? Is there excessive carbon buildup in the heads visible upon dissasembly? Or are they raced excessively, at high RPM service regularly? I need to know the EXACT circumstances that these failures are occuring under. And please don't forget, "normal driving" can lead to carbon buildup in these high performance engines.....or so I was told by bb.

I will agree that 4 failures do not indicate a serious issue, or even 20, but I'd still like to know what's going on.

[edb150]

The block has an integral sleeve, so I dont know how cylinder stresses can do this. Were these blocks all 2000 blocks? There was a piston replacement done in 2000 for piston knocking or rocking in the cylinders, I wonder if its possible that blocks that didnt have their pistons replaced progressed to cracking from cylinders cocking in their bores?

That this is occuring at the same location, is curious,

Is the engine mount located nearby? Could the engine mount being broken loose cause hammering at that location?

BBF I was referring to the cylinder pressure essentially pushing upward on the cylinder head and basically pushing the head off and cracking the block at its weak point if that makes sense. I understand the sleeve thing you talk about but it would take a lot to break the sleave {I think} And yes 4 wer 2000 and 1 was an 01

[edb150]

I would agree to close this thread Jim, but watching it for so long has me intigued. I would certainly like to know what exactly is causing these blocks to crack simply because I own a 2008 model. Assuredly it is a moot point since the Northstar is no longer in production, but there are a lot of owners out there that would SERIOUSLY like to know if there is an easy way to prevent this issue.

Now let's get into the wayback machine once again. Many years ago,(6?, 7?) I brought up the issue to bbob that carbon build up in the combustion chambers may contribute to headbolt thread pulling. I was assured at that time that that possibility was investigated by GM and no amount of testing indicated carbon buildup to be a contributory factor. This was when I owned my 1999 STS. Shortly thereafter, in 2000, there was a block redesign that was aimed at reducing block porosity issues, and just for kicks, the headbolts were drilled a little deeper too.

Now looking at the pictures, my first impression was that these blocks were frozen. But this is not a classic freeze burst type pattern, which typically blows out a chunk or section of the water jacket, complete with "hinging" of the blown out section. The forces involved in a freeze are in an outward thrust pattern (I've seen it on my boat block when the previous owner didn't drain it for winter). HOWEVER, these pictures do not indicate outward thrust or hinging of the metal away from the water jacket, and no bulging of the metal.

I think these blocks are cracking from excessive upward thrust created by the heads, acting directly on the external block material which is the weakest point now that the headbolts are not. I also would like to know what exactly is causing this excessive upward thrust. Before the head bolt threads were strengthened, I am going to assume that they would simply pull, now it looks like the block material is not up to the task and is cracking. The questions that I would like to ask is exactly how are these cars being driven? Are they driven gently, or in such a way that may lead to carbon buildup in the combustion chambers? Is there excessive carbon buildup in the heads visible upon dissasembly? Or are they raced excessively, at high RPM service regularly? I need to know the EXACT circumstances that these failures are occuring under. And please don't forget, "normal driving" can lead to carbon buildup in these high performance engines.....or so I was told by bb.

I will agree that 4 failures do not indicate a serious issue, or even 20, but I'd still like to know what's going on.

The first car was not well cared for , 150k,black oil probably overheated many times and the carbon was not excessive.I bought it and the guy did not have it long so no real history. . #2 was an older guy and the car was spotless including the inside of the motor.102k if my memory is right. There were no overheating issues it just overheated once and was towed to the dealer where I then towed it to my shop. Nice clean car with minimal carbon. #3 was a 1 owner dentist that again overheated 1 time and was towed to a shop then to mine. I own it now also so I have not taken it apart due to a very busy shop. This car is almost perfect and was babied from the way it looks. #4 has 113k and was probably overheated a few times,not apart yet so not sure about carbon. #5 was todays nightmare. This one was overheate d more than once and I just finished inserting and regasketing it. Inside of motor was clean with excessive carbon.All the threads were good but it was inserted anyway. There were no cracks when we took it apart to reseal the pan and case half and the car held coolant for about 5-10 minutes after start up. The car was on the lift about 2 feet up which is what we do at startup to check for oil leaks and such. all of a sudden it started dropping coolant and at that point I almost dident need to look under it or maybe I dident want to. I knew that where it was coming from was nowhere near anything that could be leaking except the block. Myself as well as my tech were dumbfounded. Not a good end to the day.

[edb150]

Lets get something straight, it was 'brushed off' as 'bad luck' because while we have been doing this for 10 years and have thousands of members we had NEVER EVER heard of blocks cracking.........

relax BBF i was just trying to explain to texas Jim why I am back on her talking about this.Arent we past all that?I am not trying to start trouble but you are easily excitable. I think you might agree its not bad luck anymore. Actually its more like a nightmare for me. what are the chances? Especially the last one after all our hard work. The guy who works for me went home early he was so upset.

[Cadillac Jim]

It doesn't help that the first guy from your crowd came on with his first post with excited statements about parlor tricks like shoving screwdrivers through water jackets -- something you can do with just about any engine designed for automotive use from a clean sheet of paper in the last 30 years, iron or aluminum. Or, that people in the same crowd keep coming back here trying to "educate" us about this "problem."

We have 12,000 members of this forum and we have been around for a decade now, and from the beginning Caddyinfo forums has been one of the best go-to places on the WWW for help in solving problems of *all* kinds so we get just about everybody who goes online looking for a solution; the Northstar has no secrets from us.

The Northstar has been produced in quantities on the order of 100,000 to 200,000 a year since 1993. It's one of the most successful and imitated engines ever built.

The people on chrfab use 1993-1999 blocks almost exclusively and their sand car engines are typically twin turbo 500+ hp monsters. They don't pull head bolts and they don't crack blocks. They have an open forum; check it out.

A fellow named Tom Classon in Sweden raced a Corvette with a Northstar in sports car road racing for years and did well against others using 5.7 liter bowtie racing engines. See the racing photo in the chrfab web site on the Projects page. The Northstar in 4.0 liter form (Oldsmobile Aurora bore/stroke) form was the standard engine in the Indianapolis 500 for a couple of years.

Everybody thinks that they are right. But the Northstar clearly is quite well-designed and very trouble-free. Issues with old high-mileage used cars of unknown history may seem to present a pattern to someone who makes a living working with these, but human nature sees patterns in just about everything.

References:

CHRFAB Projects

Wikpedia Page on the Northstar

2007 Forum Post about Tom Classon

[Texas Jim]

I would agree to close this thread Jim, but watching it for so long has me intigued. I would certainly like to know what exactly is causing these blocks to crack simply because I own a 2008 model. Assuredly it is a moot point since the Northstar is no longer in production, but there are a lot of owners out there that would SERIOUSLY like to know if there is an easy way to prevent this issue.

Now let's get into the wayback machine once again. Many years ago,(6?, 7?) I brought up the issue to bbob that carbon build up in the combustion chambers may contribute to headbolt thread pulling. I was assured at that time that that possibility was investigated by GM and no amount of testing indicated carbon buildup to be a contributory factor. This was when I owned my 1999 STS. Shortly thereafter, in 2000, there was a block redesign that was aimed at reducing block porosity issues, and just for kicks, the headbolts were drilled a little deeper too.

Now looking at the pictures, my first impression was that these blocks were frozen. But this is not a classic freeze burst type pattern, which typically blows out a chunk or section of the water jacket, complete with "hinging" of the blown out section. The forces involved in a freeze are in an outward thrust pattern (I've seen it on my boat block when the previous owner didn't drain it for winter). HOWEVER, these pictures do not indicate outward thrust or hinging of the metal away from the water jacket, and no bulging of the metal.

I think these blocks are cracking from excessive upward thrust created by the heads, acting directly on the external block material which is the weakest point now that the headbolts are not. I also would like to know what exactly is causing this excessive upward thrust. Before the head bolt threads were strengthened, I am going to assume that they would simply pull, now it looks like the block material is not up to the task and is cracking. The questions that I would like to ask is exactly how are these cars being driven? Are they driven gently, or in such a way that may lead to carbon buildup in the combustion chambers? Is there excessive carbon buildup in the heads visible upon dissasembly? Or are they raced excessively, at high RPM service regularly? I need to know the EXACT circumstances that these failures are occuring under. And please don't forget, "normal driving" can lead to carbon buildup in these high performance engines.....or so I was told by bb.

I will agree that 4 failures do not indicate a serious issue, or even 20, but I'd still like to know what's going on.

JohnnyG,

You make some excellent points.

I will withdraw my vote to close the thread... as long as we can stay close to "FACTS" and not wild hyperbole..

I too would like to know what is causing this... "IF" the cause can ever be found.

I have a 2006 with almost 85,000 miles on it.

It will probably have close to 100,000 by the end of the year or the first part of next year.

"IF" there is a reason that the blocks crack at 100,000 to 150,000... "I WANT TO KNOW WHAT IT IS"

I plan on keeping mine till around 125,000 to 150,000 then trading it... but if there is a problem causing cracked blocks... I may trade it much sooner...like just before it turns 100,000.

My Cadillac would "NOT" be in the class that most people think of when they think of how a Cadillac is driven.

Mine gets regular WOT exercise and regular long drives on interstates.

I don't abuse my car...they cost too darn much for that... but I do drive it fairly spiritedly.

I got into a little contest with my son this past Saturday...

Ran it up a little over 130...it was still in 3rd gear. :)

In fact, I am leaving on another trip Sat morning.

Going down along the Gulf Coast to Jacksonville Florida...then up thru the Carolinas...on thru Virginia and maybe to Niagara Falls. Then back down thru Ohio to see a friend ...then back to Texas.

Some of that will probably be a little above the posted speed limit.

Being far away from home and with Darling Wife with me...it would not be a good time to have engine trouble.

So far, the drivetrain on my Cadillac has been totally flawless.

[JohnnyG]

The only thing that I can see that these failures have in common is the overheating. I'm going to completely withdraw my theory of carbon buildup being the cause of the cracking. It doesn't appear that the causes for the overheating always needs to be pulled head bolts either. Maybe it has something more to do with the "limp home" mode of operation. From all of this information, my suggestion would be "If the engine gets hot, shut it off immediately".

Jim, If you end up heading south on I77 during your trip through Ohio, give me a call when you get to Marietta (exit 1, I77). I'd like to get a picture of the "twins", my car and yours.

[Texas Jim]

The only thing that I can see that these failures have in common is the overheating. I'm going to completely withdraw my theory of carbon buildup being the cause of the cracking. It doesn't appear that the causes for the overheating always needs to be pulled head bolts either. Maybe it has something more to do with the "limp home" mode of operation. From all of this information, my suggestion would be "If the engine gets hot, shut it off immediately".

Jim, If you end up heading south on I77 during your trip through Ohio, give me a call when you get to Marietta (exit 1, I77). I'd like to get a picture of the "twins", my car and yours.

I will probably start a thread on the trip...now that I have learned how to post pics..

I am taking my laptop so that I can keep up with whats going on.

I am not sure of my route yet or just where we may be going...

We don't make many firm plans when we take off driving...we just "GO" and see where we end up at.. LOL

But coming down that way is a good possibility...

[Cadillac Jim]

Looking at post number 80,

Link to Post #80

the block was cracked when you started it, going by the description of a sudden leak a few minutes after the engine was started the first time after major work. I would suspect that something gave way during the Timeserting operation, going by the location of the leak.

[edb150]

Looking at post number 80,

Link to Post #80

the block was cracked when you started it, going by the description of a sudden leak a few minutes after the engine was started the first time after major work. I would suspect that something gave way during the Timeserting operation, going by the location of the leak.

No way it was cracked as I filled it with coolant and it sat an hour while I finished assembling it. i do this to try and get the system full before startup. The crack is fresh not to mention that I really look these motors over while ther on the engine stand getting the lower case and pan resealed. It troubles my mind but we will get past it somehow.

[Cadillac Jim]

Uh, after assembling an engine that had just undergone work, including Timeserting -- which includes deep block-drilling and tapping, then stud insertion, then re-torquing -- the engine was filled with oil and coolant, and started. A few minutes later the break out of the side of the water jacket manifested itself; broken metal manifested itself without being touched. Whatever was there happened before the engine was assembled.

I have seen people in a shop rolling a brand-new 427 short block, right from the Chevrolet dealer, across the floor like a barrel, to move it. A big block can take that kind of abuse without damage, except possibly scratching the tin plating on the pistons, but just about anything else would risk a perforation of the water jacket. I would infer from your post that the block wasn't protected on an engine stand 100% of the time while it was out of the car. Even on an engine stand it could have been bumped or hit by accident. Or, it could have been hit while it was being removed or replaced into the car or engine cradle subframe. A less likely scenario is that some misstep in the Timesert installation damaged the block. It's very possible that nobody realized that the block was damaged when it happened.

Your description of what happened tells me that whatever it was, it didn't just happen because of some problem with the block from the factory. It happened *to* the block between the time the hood was raised to pull the engine and the time the car was next started.

If the cause is a simple small perforation of the water jacket, I would look at welding it.

[firefoot0315]

Like Adallak said earlier, I'd like to hear where GM weighs in on this phenomenon/trend/whatever-you-want-to-call-it.

[BodybyFisher]

I am going to call around to my scrap yard friends and see what I can find out.

I do know one thing, there are a LOT of AHOLES out there that put PURE WATER into there cooling system when then are leaking or using coolant because it gets TOO expensive to keep putting COOLANT into a broken cooling system, I can't help but think that many of these engines have been frozen sitting in junk yards or someone driveway.

[bdbarb]

Cracked block here on a 2003 SLS, just rolled into 94k miles. I took her in for an oil change at the local dealer. The next day the antifreeze was low. Refilled at the dealer. The next day the antifreeze was low. Took it to the dealer for a pressure test, 140 dollar diagnostic. They found a hairline crack in the front by the oil filter. They cannot find a new block for this, recommended a junk yard block and doing a rebuild. They put pins (a chemical tab) that are ok in liquid but when hitting air will seal the crack in the antifreeze. This is warned to NOT be the permanent fix, only temporary until a new block can be installed. It's always been well maintained, I'm the second owner as of 63k miles. The dealer mechanics all stood around and between 6 people, all agreed that this is the typical death of the 32 Valve Northstar. I love my car, but am going to make sure the next Cadi I purchase has the 3.6 liter v6 in it.

[Texas Jim]

bdbarb...

Well if all six of them agreed... then all six of them are wrong...

That IS NOT the typical death of the NorthStar... and especially not at that mileage.

There are a LOT of Northstars that go 200,000 plus miles and never have that problem.

Mine has 132,000 on it and I have never had an issue with it...

[Cadillac Jim]

If it has a crack in the block in the front by the oil filter, it was very likely caused by mechanical damage, like driving over a curb and hitting the oil filter, a lift pylon or floor jack on the engine instead of the frame, etc. This is *very* rare.

I once had a friend who came to the USA from central America and bought their first car. When it was three years old, it needed a battery and the dealer convinced her that changing a battery was so expensive that she would be better off trading the car in, and she did. This was NOT a GM car or dealer (it was an import make that I'm not going to identify because there is no way that the manufacturer would tolerate that if they knew).

The fact that all of them agree that it's a crack, and that this is "typical" and are using words like "end of life" have me thinking

I think you should get a second opinion. It doesn't have to be a Cadillac dealer, or even a new car dealer, but try to find someone honest and ASE certified through your friends and associates if you don't have another dealer nearby. Tell them *nothing* about your recent experiences, just that you just got the car and are losing coolant; you want a clean sheet of paper.

[rockfangd]

That is news to me. I have not run into any cadillac with a cracked block And I have seen many from all generations with the Northstar. My opinion is that is way too much of a coincidence to occur right after an oil change. Did you see the crack for yourself?

[Cadillac Jim]

This is a Topic from 2010 in which a couple of cracked blocks were shown. These were clearly stress cracks, one of them clearly from force on the oil filter or adapter. Another time we had some guy come on and say that block cracking was a problem, but a red flag came up early when he stated that you could put a screwdriver through the water jacket of a Northstar (you can do that with a lot of engines, including some iron ones). It turns out that he was rolling them around on the floor instead of using an engine stand when they were out of the car. My thinking ever since is that if someone comes up with a Northstar block that is actually cracked, look for mechanical abuse like high-centering or jacking the car up by the oil filter or some such.

[rockfangd]

Lol I love to roll my Northstar on the floor. Who doesnt

[Cadillac Jim]

Lol I love to roll my Northstar on the floor. Who doesnt

[truant]

1999 Deville. 225k miles on the chassis. Third engine, second transmission. That should say a lot all by itself. Interior is near mint, except the steering wheel which shows the thin dye'd layer wearing through the unecessarily cheap material selection.

First two engines were from GM directly. Both died of head-gasket failure. The second time they told me they couldn't get a GM block because GM had stopped making them, so Jasper it was.

The current engine is from Jasper. They did a good job on it, timeserts, and otherwise full service, and it runs fantastic. However, it cracked after 150k-175k miles of babied service. 25-45minutes each way, highway, daily driver, etc etc.

I do all my own work, except for the engine and tranny swaps. The tranny died during the brief service of engine number two (leaking fluid past some plate or other.. I forget).

Some members wish to say that the nothstar engine, an engine ironically named after a star that never moves, is very reliable. I disagree on the facts of the matter. Nearly 100% die of headgasket failure. After the "repair" they now seem to crack after roughly 3000 hours of service, or heat cycles, whichever you wish to count.

My crack went undetected for some time, but I always noted some weeping coolant, which try as I might, I could not locate. After recently replacing the starter, having removed the air intake, servicing everything on the top-side.. including new heater hoses on the backside, where I found the silicone hoses disintegrating in my hands as I handled them. I thought for sure I had found the source of the weep. However, by sheer accident, I left the radiator cap loose returning to work monday. I parked it, rejoicing at the improved 'feel' of the engine with the new intake gaskets, and at lunch noticed all of my coolant on the ground.

Ironically, the pressure cap had been holding a vacuum on the system all this time, but releasing it revealed the crack.

Some suggest mishanding of the car. Mine has never kissed a curb, been jacked in the center, in an accident or other. This car has been well loved.

My engineering analysis of the crack, it is a simple heat-cycling metal fatigue crack in the maximum stress area of the block. Yes, I am an engineer.

The root cause is improper metal casting design, which failed to properly model or otherwise acount for the differing rates of expansion in aluminum castings across varrying thicknesses. This creates stress focal-points, and a maximum temperature cycle life. It's easy to test for, even using technology only available in the 90's, but I digress.

The actual design failure was the head-bolt design. But contributing to this problem is the new head-bolt rework configuration.

The goal of the rework is simple: Push the design beyond any warantee period, to escape the financial risk involved with a mass-recall. I work(ed) in the industry, you could ask how I know, but I'd only say "here's your sign".

Three engines... all with seemingly fatal flaws. One, a statisical blip. Two, bad luck. Three??? From the same owner???

The british made an ALUUMinEUm V8 engine for 40-50 years. They bought the design from GM years ago. Those engines are fine..

The northstar was not properly tested. I have proof, but I cannot share the documents for obvious reasons.

Now, the 1999 model.. newer models may have been fixed. My documentation stops in 2001. But generally speaking, this caddy owner.. who hs enjoyed 12, that's 12 nice cars.. is probably going to leave it at 12, and try something else. Gosh i really wanted an SRX too.

Warm regards.. but cold feet (no fluid in the heater core anymore, uhh ohh, another $15).

[PAUL T]

I had a business partner that had a 2000 Deville. After about 120,000 miles it started loosing antifreeze. We suspected a headbolt pulled but when he took it to a local mechanic he said it was a cracked block. My friend just put some stop leak in it and it stopped the leak. He drove it for another 20,000 miles then traded it off. The stop leak held all the rest of the time he had it.

[Cadillac Jim]

There are over a million Northstar engines out there. About 15% of them (see survey elsewhere on this site) have head gasket problems. Most head gasket problems follow a period of four to seven years without a cooling system flush, which is required every three to four years with red antifreeze. The North Star is the standard for navigation and has been for thousands of years.

I'm sorry you had bad luck with your car. Please come back when we can help you.