Timeserted Northstar

[adallak]

Scheduled coolant changes likely reduce the probability of Northstar’s notorious headbolts- pull-out problem. I heard many times that electrochemical reaction between steel bolts and an aluminum block might be responsible for the same problem as well.

1. Are they stainless bolts?

2. Anodized steel?

I assume the aluminum internal threads are not treated.

3. Does the factory coat the bolts with something before screwing them in?

Now, I heard many times that the timeserted engine is better than new one… It may be true or not. It usually takes some 6-8 years before the bolts fail. Probably timeserted engines just did not have enough time passed to fail again. I do not know. The insert is steel as well, right? So there will be the same electrochemical process between the insert and the block.

4. What is the thread pitch (external) of timesrts?

Thank you.

[MrEldo97]

Scheduled coolant changes likely reduce the probability of Northstar’s notorious headbolts- pull-out problem. I heard many times that electrochemical reaction between steel bolts and an aluminum block might be responsible for the same problem as well.

1. Are they stainless bolts?

2. Anodized steel?

I assume the aluminum internal threads are not treated.

3. Does the factory coat the bolts with something before screwing them in?

Now, I heard many times that the timeserted engine is better than new one… It may be true or not. It usually takes some 6-8 years before the bolts fail. Probably timeserted engines just did not have enough time passed to fail again. I do not know. The insert is steel as well, right? So there will be the same electrochemical process between the insert and the block.

4. What is the thread pitch (external) of timesrts?

Thank you.

To answer your questions:

1. No

2. Black Nitrate

3. Yes, a thread sealer

4. I'll check, though the outside thread pitch is coarser than the inside.

My Timesert repair has 18,000 miles on it.

[KHE]

Scheduled coolant changes likely reduce the probability of Northstar’s notorious headbolts- pull-out problem. I heard many times that electrochemical reaction between steel bolts and an aluminum block might be responsible for the same problem as well.

1. Are they stainless bolts?

2. Anodized steel?

I assume the aluminum internal threads are not treated.

3. Does the factory coat the bolts with something before screwing them in?

Now, I heard many times that the timeserted engine is better than new one… It may be true or not. It usually takes some 6-8 years before the bolts fail. Probably timeserted engines just did not have enough time passed to fail again. I do not know. The insert is steel as well, right? So there will be the same electrochemical process between the insert and the block.

4. What is the thread pitch (external) of timesrts?

Thank you.

The aluminum threads in the block are not treated with any coating.

The Timeserted Northstar engine is stronger than new - there is much more surface area that is in contact with the block due to the larger outside diameter of the inserts. There is then steel on steel contact between the head bolt and the Timesert.

[adallak]

Scheduled coolant changes likely reduce the probability of Northstar’s notorious headbolts- pull-out problem. I heard many times that electrochemical reaction between steel bolts and an aluminum block might be responsible for the same problem as well.

1. Are they stainless bolts?

2. Anodized steel?

I assume the aluminum internal threads are not treated.

3. Does the factory coat the bolts with something before screwing them in?

Now, I heard many times that the timeserted engine is better than new one… It may be true or not. It usually takes some 6-8 years before the bolts fail. Probably timeserted engines just did not have enough time passed to fail again. I do not know. The insert is steel as well, right? So there will be the same electrochemical process between the insert and the block.

4. What is the thread pitch (external) of timesrts?

Thank you.

To answer your questions:

1. No

2. Black Nitrate

3. Yes, a thread sealer

4. I'll check, though the outside thread pitch is coarser than the inside.

My Timesert repair has 18,000 miles on it.

1. Is the same thread sealer used with timeserts?

2. Can you compare the outside thread pitch of a timesert to one of 1993-1999 Northstar headbolt threads.

3. What is the pitch of 2000 and 2004 Northstar headbolts. These are the years the pitch was changed.

Both milage and time contribute in bolts pulling out. The first represents an integral amount of stress on the bolts, while time (obviously including one the engine idles or is off) contributes into extent the thread has been affected with electrochemical reaction (if there is such reaction between sealed threads of the bolt and aluminum block).

[adallak]

Scheduled coolant changes likely reduce the probability of Northstar’s notorious headbolts- pull-out problem. I heard many times that electrochemical reaction between steel bolts and an aluminum block might be responsible for the same problem as well.

1. Are they stainless bolts?

2. Anodized steel?

I assume the aluminum internal threads are not treated.

3. Does the factory coat the bolts with something before screwing them in?

Now, I heard many times that the timeserted engine is better than new one… It may be true or not. It usually takes some 6-8 years before the bolts fail. Probably timeserted engines just did not have enough time passed to fail again. I do not know. The insert is steel as well, right? So there will be the same electrochemical process between the insert and the block.

4. What is the thread pitch (external) of timesrts?

Thank you.

The aluminum threads in the block are not treated with any coating.

The Timeserted Northstar engine is stronger than new - there is much more surface area that is in contact with the block due to the larger outside diameter of the inserts. There is then steel on steel contact between the head bolt and the Timesert.

Apparently if timeserts fail they, will fail rather at aluminum/steel than steel/steel contact areas. If a larger pitch solves problem, why we see 2000 generation Northstars with the same problem? Not large enough? Is the bolt pitch on 2000 Northstars smaller than external one on first generation timeserts? How about 2004 bolts? For some reason, I seriousl doubt coolant has much (if anything) to do with bolts pulling out. Collant obviously cannot even get involved because there is a thread sealant (unless the latter degrades as well). Any way, it's a shame to see so many Northstars failing because of this relatively minor problem. Minor in terms of possible solutions available but never taken place.

[JasonA]

From what I understand, the problem is significantly reduced from 2000 on. The bolt threads were elongated I believe in 2000, and the pitch stayed the same. Then in 2004, the pitch was also changed, and the bolts may have been elongated again. Even with changes to the head bolts, head gasket issues are not impossible to have, on any engine. Someone on the Chrysler minivan forum had his 3.8L V-6 engine in for head gaskets at only 27,000 miles. Those engines are known to be generally bulletproof and good for at least a quarter million miles, and are certainly not known for head gasket failures. But stuff can always happen.

[BodybyFisher]

I believe that there are multiple modes of failure

1) I do believe that once the anti-corrosive package is used up in the Dexcool it becomes acidic and damages the head gaskets. I believe this because the GURU said so and believe him to be a man of character.

2) I believe that in some cases there are casting defects, the change in the aluminum that AJ showed us was either due to a bad casting or a change in the aluminum over time either from acid, electrolysis, etc

3) I believe that the older Northstars were designed with 'just adequate' bolts and they were redesigned twice as a result. I think at 111K miles its just a matter of time with mine.

4) I can't help but think that if carbon is allowed to build up on the piston and allowed to knock, that the knocking is PUSHING the head up physically, the guru disagreed with this theory, but it stands to make sense.

I used to think that head gasket problems were the result of the high compression that equated to high output (275 and 300 HP), but if you look at the Ford 32 valve 4.6 it puts out 280 HP and I do not believe they are susceptible to head gasket problems. I would love to compare the two engines side by side and see the differences in head bolts, block and metallurgy

[BodybyFisher]

Here is something to drool over, and I HATE Fords (http://en.wikipedia.org/wiki/Ford_Mustang_SVT_Cobra)

Debuting in early 2002, the 2003 Cobra came with a supercharged 4.6 L DOHC engine rated at 390 hp (291 kW) and 390 lb·ft (529 N·m) of torque. It was later determined that Ford had underrated the Cobra, as actual output averaged 430 hp (321 kW) and 430 lb·ft (583 N·m) of torque. Numerous improvements were made to the powertrain and driveline to handle the increase from the previous model year. A cast iron block was used instead of aluminum, with stronger internals (forged Zolner pistons and Manley H-beam connecting rods) to handle the 8 psi (55 kPa) of boost delivered from the supercharger. Other improvements include the use of an aluminium flywheel connected to a Tremec T-56 six-speed transmission, 3.55:1 rear axle ratio and stronger 31 spline half shafts with revised upper and lower control arms

[Ed Hall]

The questions was whether a timeserted Northstar was better than new. Well, it depends on the condition of the engine being rebuilt. From what I hear from those that do this job of timeserting these engines regularly, there are a certain significant percentage of engines that come through in which the block is rejected. The bolt holes are too corroded to ensure that even timeserts or bigserts would hold for a long period. The way that the mechanic determines whether or not the block is usable is to examine the shavings when drilling out the bolt holes for the timeserts. If the shavings look powdery, the block is toast. Anyways, this is just something else to be aware of if you're thinking about timeserting your Northstar engine.

[BodybyFisher]

The questions was whether a timeserted Northstar was better than new. Well, it depends on the condition of the engine being rebuilt. From what I hear from those that do this job of timeserting these engines regularly, there are a certain significant percentage of engines that come through in which the block is rejected. The bolt holes are too corroded to ensure that even timeserts or bigserts would hold for a long period. The way that the mechanic determines whether or not the block is usable is to examine the shavings when drilling out the bolt holes for the timeserts. If the shavings look powdery, the block is toast. Anyways, this is just something else to be aware of if you're thinking about timeserting your Northstar engine.

Yes this is what we learned from AJ, did we determine what does this?

[JimD]

.... For some reason, I seriousl doubt coolant has much (if anything) to do with bolts pulling out. Collant obviously cannot even get involved because there is a thread sealant (unless the latter degrades as well).

Based on years of reading (and saving) comments by our nameless guru on headgasket issues, I hold the position that gasket failure leads to bolt hole thread contamination. Headbolt threads are treated to address the galvanic reaction of steel against aluminum. The gasket is designed to keep the bolt dry since coolant in contact with the steel/aluminum junction would behave as an electolyte.

Treated steel bolts in a dry aluminum hole and galvanic corrosion is contained. Life is good.

Then the gasket fails for any number of reasons including poor service intervals or plain old bad luck. When the gasket fails in such a way as to allow coolant (electrolyte) to contact the bolts, bad things begin to happen to the steel/aluminum junction. Eventually, the galvanic corrosion and thread damage will reach a level where the clamping force is reduced and the gasket damage becomes obvious.

None of which explains why the bolt specifications were changed for 2000 and again during the 2004 model year. Our guru started feeling the heat in 2006 and no one had an opportunity to put the question to him.

[Bruce Nunnally]

I would prefer that engines never have head bolt / head gasket issues. However, if they do have a problem, in my opinion the problem in the case of the Northstar is that it is such an EXPENSIVE problem. This seems to be caused by a combination of the FWD packaging, the engine/transmission coupling, and Cadillac Dealer profit expectations on repair work. If this was a RWD vehicle and easy to replace the head gasket with the engine in place, this might be a $1,200-$1,500 repair. At that price level it would be bad but manageable. When you talk about deciding between a) a $5K repair or a $2K Remove&Replace plus a used engine or c) a new engine install at the dealer for $10K, THAT's the problem!

I would like to see Cadillac offer a service & warranty program for the Northstar that 'warranties' the engine for any head gasket repair and head bolt service will cost the customer no more than $2K per occurance for the life of the Cadillac. For example, you have a Cadillac with 145K miles on it, and the head bolts pull. You bring it in to the dealer, and they timesert the heads and change the gasket, you pay $2K, and you drive home.

[KHE]

Scheduled coolant changes likely reduce the probability of Northstar’s notorious headbolts- pull-out problem. I heard many times that electrochemical reaction between steel bolts and an aluminum block might be responsible for the same problem as well.

1. Are they stainless bolts?

2. Anodized steel?

I assume the aluminum internal threads are not treated.

3. Does the factory coat the bolts with something before screwing them in?

Now, I heard many times that the timeserted engine is better than new one… It may be true or not. It usually takes some 6-8 years before the bolts fail. Probably timeserted engines just did not have enough time passed to fail again. I do not know. The insert is steel as well, right? So there will be the same electrochemical process between the insert and the block.

4. What is the thread pitch (external) of timesrts?

Thank you.

To answer your questions:

1. No

2. Black Nitrate

3. Yes, a thread sealer

4. I'll check, though the outside thread pitch is coarser than the inside.

My Timesert repair has 18,000 miles on it.

1. Is the same thread sealer used with timeserts?

The threadlocker is factory applied to the replacement head bolts. There is no way to reliably apply it in the field - that is why replacement head bolts are included with the kit and must be used. It is not the same threadlocker that is applied to the Timesert to help retain it to the block. From memory, that sealer is Loctite 260 or 262. The Timesert is mechanically swaged into place with the installation tools and the threadlocker is there for added insurance.

Scheduled coolant changes likely reduce the probability of Northstar’s notorious headbolts- pull-out problem. I heard many times that electrochemical reaction between steel bolts and an aluminum block might be responsible for the same problem as well.

1. Are they stainless bolts?

2. Anodized steel?

I assume the aluminum internal threads are not treated.

3. Does the factory coat the bolts with something before screwing them in?

Now, I heard many times that the timeserted engine is better than new one… It may be true or not. It usually takes some 6-8 years before the bolts fail. Probably timeserted engines just did not have enough time passed to fail again. I do not know. The insert is steel as well, right? So there will be the same electrochemical process between the insert and the block.

4. What is the thread pitch (external) of timesrts?

Thank you.

The aluminum threads in the block are not treated with any coating.

The Timeserted Northstar engine is stronger than new - there is much more surface area that is in contact with the block due to the larger outside diameter of the inserts. There is then steel on steel contact between the head bolt and the Timesert.

Any way, it's a shame to see so many Northstars failing because of this relatively minor problem. Minor in terms of possible solutions available but never taken place.

Keep in mind that the internet exaggerates the perception of failures in cars - rarely does someone seek out the internet to brag how trouble free their car is. They seek out the internet for help on issues they're having with their car. For every one with bad headgaskets you read about, there are thousands of cars that do not have the problem. My '96 has 128,000 miles on it and the engine has never been touched. It also has had regular coolant changes since I bought it at 54,000 miles....

[JasonA]

My former '97 has over 165,000 on it now. Besides the water pump, no seals have ever been replaced in that engine. Runs like a champ still.

[adallak]

My former '97 has over 165,000 on it now. Besides the water pump, no seals have ever been replaced in that engine. Runs like a champ still.

You are one of those 85% lucky ones,

[CadillacETC1997]

1997 ETC HGS failed at 100K and were replaced by the dealer

now she sits at 107K and im 99% sure they have gone again appointment is scheduled for Monday...

thank god for 12mth/12k warranty

[MrEldo97]

now she sits at 107K and im 99% sure they have gone again

If so the dealer screwed up the job - most likely the tech working on your car rushed it and took short cuts to get the job finished under book because he's working flat rate.

You can't rush this job! I made my Timesert repair myself, followed the instructions implicitly and I now have 18 months and 18,000 miles on my repair

and my '97 Eldorado runs exceptionally well.

[CadillacETC1997]

im not worried about it

like i said the dealers gonna have to eat it

its still under warranty...

[BodybyFisher]

im not worried about it

like i said the dealers gonna have to eat it

its still under warranty...

If I were you, I would be worrying.

You did not specify if the block was timeserted at the time of the repair 7K miles ago. I just looked back and none of the threads you started involved head gaskets, overheating, etc but you have been a member since mid 2006. You were the member who commented that Wester's could hack the Northstar.

They probably did not timesert the engine, and if they did, they did not do it correctly given how fast it failed. Typically, unless you ask, and pay for it, they will not automatically timesert the engine block.

Now, if what you say is true and the bolts pulled again:

1) if they did timesert your block and a timesert pulled, now their only recourse is a bigsert and dealers typically don't do them. They will blame the failure on the block metal being damaged from corrosion and they will say you need a new block (read that as engine). Honestly, the block's aluminum COULD be damaged from corrosion and not salvageable, see a post by AJ on the subject.

2) if they did not timesert your block and a bolt pulled and it needs head gaskets again. You can bet the warranty company will put up a kicking and screaming fight NOT to pay for this repair again. You will probably be shown corroded aluminum and informed that the block needs to be scrapped.. The warranty company will NOT pay for the timeserts (foolish if you ask me for them not to pay for timeserts on the initial repair to do the job correctly and avoid problems), you would need to pay for them, assuming of course they agree to do this job a second time, which if they do, will amaze me. The warranty company's beef is really with the dealer and why the repair did not hold 12K miles, when Do It Yourselfers continually get it right and drive off into the Northstar sunset with a properly repaired engine. You can bet that the dealer will show the reasons your repair failed. It will be interesting to see what comes out of this, please post what happens.

All the while, you will steam up and the bottom line is that GM's good reputation suffers because of poor repair procedures. IF GM has not issued a bulletin on the proper method of RE-INSTALLING the head bolts by now it is a shame. The problem that arises is the extra cost of timeserting, who forks that up, the dealer, the tech or GM? So the status quo remains, the dealer will keep repairing NSs without timeserting them. They cant say to you as a customer, listen we will "FIX" this but if you really want it FIXED you need to PAY $800 for timeserting. So they remain mute. GM gets hurt over this.

Me?, as a strong proponent of "if you don't do it right, don't do it at all", if I were GM, I would build it right when I casted it, with STEEL inserts strongly impregnated into the block aluminum. But that is me. And for those bean counters that say it will cost too much money, BS, sit down and watch HOW THEY BUILD IT, on the DISCOVERY CHANNEL for a month, and tell me how much of an problem it would be.. It might add $8.00 to the cost of each engine but MILLIONS to their reputation, and that is the point! Get the bean counter OUT of the equation when it comes to reputation.

They should pay one mechanic and a helper a SALARY, a good salary to do this type of work. Trying to get this work done with time constraints is foolish. But who would pay for that? GM? or the dealer? see the pattern here? So who suffers?, GM's reputation and you the customer

Given that time is money, the DEALER, is NOT the place to get a complicated and time consuming job done. Start to think about alternative plans if they come back and say the engine is NOT salvageable so as not to be disappointed and caught off guard when they do.

As I said, it may be legitimately NOT salvageable or the failure could be because it was not timeserted.

[BodybyFisher]

If I was a younger man, I would start a shop to do this kind of dealer non profitable work and fine tune the procedure down to a science. Its all about outsourcing, let the dealer mechanics do the safe, profitable stuff quick turnaround things like brakes, oil, leaks, etc. , and send the time consuming work out to a specialist, like they do with transmission rebuilds....

[MrEldo97]

I would prefer that engines never have head bolt / head gasket issues. However, if they do have a problem, in my opinion the problem in the case of the Northstar is that it is such an EXPENSIVE problem. This seems to be caused by a combination of the FWD packaging, the engine/transmission coupling, and Cadillac Dealer profit expectations on repair work. If this was a RWD vehicle and easy to replace the head gasket with the engine in place, this might be a $1,200-$1,500 repair. At that price level it would be bad but manageable.

To be sure. The biggest problem with Timeserting a Northstar is that d**n FWD configuration. I spent more time dropping the cradle and re-installing the cradle than doing everything else...

[MrEldo97]

If I was a younger man, I would start a shop to do this kind of dealer non profitable work and fine tune the procedure down to a science. Its all about outsourcing, let the dealer mechanics do the safe, profitable stuff quick turnaround things like brakes, oil, leaks, etc. , and send the time consuming work out to a specialist, like they do with transmission rebuilds....

Excellent idea!!!!!

[KHE]

My bet is the dealer did Timesert the engine the first time and screwed something up. Now, they will say that the block is unreparable and want $ for a reman engine since dealers do not typically use the Bigsert. I don't buy the "some blocks can't be repaired because the shavings are powdery either...

The flat rate compensation system at dealers is flawed and needs to be replaced with a syatem that provides fair compensation and guarantees a quality repair.

[jerrymac]

As far as the question, is a timeserted NS better than new, I can only say that I hope I never have to find out.

Although my 97 Eldo ETC has only 64,000 miles on it, it is however over 10 years old and has never had any type

of engine problems or overheating problems. In fact, the only parts that I have ever changed are brakes, blower motor, and just recently, the fuel pump. The blower motor was the worst of them to change. I haven't owned the car since it was new, but since I've had it I change the coolant every 2 years, but I don't use the Dexcool.

I use the same coolant that we use in the Mack trucks at the dealership that I wrench at. It's rated protection is 5 yrs, 300,000 miles and is silicate free, and comes already premixed at 50/50 right out of the container. I don't know for sure if the regular coolant changes help to prevent possible problems, but then again, I am pretty sure that it can't hurt.

[MrEldo97]

The flat rate compensation system at dealers is flawed and needs to be replaced with a syatem that provides fair compensation and guarantees a quality repair.

To be sure, that's the heart of the problem. Dealers treat techs like slaves. The hourly rate now is generally $100.00, in some cases more, and the techs don't see much of it. And then there is the inflated prices for pasrts... Of course the dealers scream poverty if not for their charges. But...How many dealership owners have become gazillionaires?