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Discussion Starter #1
Hi there fellas,
I just got a brand new N* engine put into my 99 STS. The previous engine's head gaskets blew after about 60,000 miles. Is this going to happen to my new engine when it gets 60,000 on it? I am wondering how I can avoid this problem with my new engine. Any precautions/maintenance tips? Should I sell it soon?

Thanks,

-Mike
 

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White Diamond '03 DHS (with DTS floor shift)
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While it is not unheard of, it is not as common as one would think by reading this forum. People come hear when they have a problem so your view here is a bit skewed. Just sold my '97 Deville with 107K and never had a problem. Many others here with much higher milage and no problems.Then there are the unfortunate ones like yourself. I wouldn't worry about it. Especially if you have a "new" engine.

The biggest thing you can do to help prevent it is change the coolant as required in the owners manual.
 

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02 STS
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I would add, and this is 100% speculation, do the Carbon blow out technique regularly too...

Almost every post from members complaining about head gaskets starts with... "I don't understand... The car has been babied since new"

I have never seen a post like "I love to drive the snot out of this car... Guess I pushed her too hard and the head gaskets blew"

PS... I drive the snot out of mine, and I have already changed the coolant once. No problems (so far) I'm just over 60,000 Miles.

While I hold my breath over mine... Good Luck with your new motor
 

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Ranger said:
While it is not unheard of, it is not as common as one would think by reading this forum. People come hear when they have a problem so your view here is a bit skewed. Just sold my '97 Deville with 107K and never had a problem. Many others here with much higher milage and no problems.Then there are the unfortunate ones like yourself. I wouldn't worry about it. Especially if you have a "new" engine.

The biggest thing you can do to help prevent it is change the coolant as required in the owners manual.
I agree with Ranger, and I'll note that a 99 is almost two years overdue for a coolant change, regardless of the mileage. The Dexcool coolant used in Northstars from 96 to present is good for 5 years or 100k miles, whichever comes first. If the additives become depleted from lack of changing, there is nothing protecting the cooling system or the head gaskets from corrosion. Was the coolant ever changed in your 99 as far as you know? Now that you have a new engine, the coolant is good for another 5 years assuming they used Dexcool.
 

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93 STS N*
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I have a 93sts w/190000km changed coolant when I bought it, it was at 130000km when I bought it. The original coolant was the green coolant, I changed it to dexcool is there a problem from upgrading to dex from the green??? I'm pretty sure I have no head gasket problems, never over heated when I owend it, are there any sings of head gasket going either then blowing white smoke and over heating. Only problem I sometimes get is code p132 but it turns on for a couple of seconds, also the car doesn't really like to slow down when I let off the gas unless thats normal?
 

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pimpjuice01 said:
I have a 93sts w/190000km changed coolant when I bought it, it was at 130000km when I bought it. The original coolant was the green coolant, I changed it to dexcool is there a problem from upgrading to dex from the green??? I'm pretty sure I have no head gasket problems, never over heated when I owend it, are there any sings of head gasket going either then blowing white smoke and over heating. Only problem I sometimes get is code p132 but it turns on for a couple of seconds, also the car doesn't really like to slow down when I let off the gas unless thats normal?
It's fine to mix green and orange coolants, but you will need to change it out every 2 years or 30k miles for the rest of the car's life, no matter which coolant you put into it from now on. Orange to green coolant is more of a downgrade than an upgrade. Also, be sure to use the supplement as recommended in a hose and not in the surge tank.

If it doesn't slow down when you let off the gas, you may have a sticky throttle cable or blade, or the spring is broken or you have a vacuum leak. You should clean the throttle body to begin with and look/listen for leaks after checking the throttle cable and blade spring. Use the Search feature above or look in the Tech Tips section for TB cleaning procedures. It's documented here many, many times.
 

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Hello and congratulations on your new engine. I have been looking everywhere for either a rebuilt or used, or new engine, and was told none are available anywhere in the nation. Consider yourself fortunate to have one. With that said, I really would like to know where you were able to find your engine? Currently I am using ThermaGasket to patch blown head gasket, so be nice to have backup plan just in case.

Avoiding blown Head Gaskets? All you can do is stay away from red line, keep cooling system maintained properly. I still have no idea why mine blew.
 

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Not sure about the... stay away from red-line... I red line mine about 7 time a week... By my count she has been past 6500 at least 600 times since I have had her... No issues with the Motor, Trans or Suspension...

A clean combustion chamber is a happy combustion chamber!
Not to mention the N* sounds awesome over 5000 RPM!
 

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Discussion Starter #9
rfishing said:
Hello and congratulations on your new engine. I have been looking everywhere for either a rebuilt or used, or new engine, and was told none are available anywhere in the nation. Consider yourself fortunate to have one. With that said, I really would like to know where you were able to find your engine? Currently I am using ThermaGasket to patch blown head gasket, so be nice to have backup plan just in case.

Avoiding blown Head Gaskets? All you can do is stay away from red line, keep cooling system maintained properly. I still have no idea why mine blew.
THANKS EVERYONE FOR SPEEDY REPLIES. I appreciate all the input and comments.

RFISHING, as to where I found the engine, I do not know, because Gooley Cadillac in St. Clair Shores, Michigan did all the work under warranty. It was about $7800 of parts and labor for the new engine install. It also took 18 days from diagnosis of gasket failure to completion of overhaul. If you want to contact this dealership, the # is (586) 772-8200.

As for the redlining, (aka WOT carbon cleaning method) I am not sure if it is bad or good, based on the opinions of the forum members. I dont see how it can be so great for the engine. On the other hand, it seems that it cant be really bad, either. I just dont see how a motor of this caliber (the Northstar), which is a magnificently-engineered masterpiece, can blow headgaskets when redlined. So, I tend to keep in between. No redlining, and no babying.
 

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You are all right... No-one is sure why head-gaskets on N*'s "go"... There are lots of theories... Thermal expansion, micro cracks, bad batch of Mexican gaskets in '97, coolant corrosion...

Here is mine... The N* engine has a very tight quench area within the combustion chamber. This is the "squish" space between the top of the piston and the bottom of the head. "Babied" engines tend to build up carbon deposits in this space. This reduces the combustion space and can lead to knock and ping... But it also creates a nasty carbon sandwich where the piston starts to transmit mechanical force through the carbon build-up to the head... This hammering action, if it occurs, is guaranteed to weaken/strip head bolts and damage a head gaskets...

One thing I could never understand, and our ex-guru could never answer is why can hot rodders swap heads on the aluminum LS1 block without timeserts and we can't.

I would love to talk to a mechanic who does N* timeserts to see if the majority of these engines are full of carbon... If they were this would solve this mystery and provide an easy and free procedure for all of us to protect our engines.
 

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Discussion Starter #11
That is a great theory.
I am still confused though, as to HOW can WOT burn off carbon. Is it because the cylinder gets hot? If so, this doesnt make sense because I would think the cylinder stays the same temp when running, no matter what the rpm is. Am I right or no?:hmm:
 

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White Diamond '03 DHS (with DTS floor shift)
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I once asked out former guru that question. As usual, his answer was quite lengthy and detailed. I think it had something to do with increased heat and cylinder pressures or something like that. I wish I had saved it.
 

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speaking of head gaskets lol reading this has got me thinking... ive added coolant to my car twice since i bought it in october now i have never gotten a low coolant warning, and the temp guage never goes past 1/2 way mark.. but where is the coolant going lol.. its had about a gallon added since oct. oh this is on the 96 sls 129k miles. i had the oil changed the day i bought it and the tech said it was really watery but didnt know how old it was either ( it was really gross) but didtn look like it had coolant mixed ( also has the green coolant)
 

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Eldorado 95
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Once upon a time in the past I bought a new BMW 525 TDS touring with my the last money I had. At this time I my son was just be born, I was building a new house for my family and my old VW Rabbit goes to junk. I drove the BMW with smooth hands, no full speed, every service but after 2 years the head gasket gots blown out. I payed at least 7000.- German Marks for the repair of this kind of shit, even the car has runned 55Thousend miles. In 1999 after this BMW my financial situation was enormiesly better and I bought an new Jaguar XJR Sedan, everyone of my friends was warning me because of this car, too difficult, too expensive and so far. Well I turned the key of the car at the dealer and I drove very slowly for the first 10 miles, but as I reached the german autobahn I took a race with a Porsche 993 and I won!!. From this time on I never spared my cars and today my jag had runned 80thousend miles without a damage. This means the same for my 96corvette or my 95eldorado. What I want to say is, you can spare your car to death, like we say in bavaria, but when I put the pedal to the metal, I finally have enough fun though even a repair isn`t quite so bad as without. The head gasket damege comes or it comes not. Greetings from bavaria
 

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1989 Sedan DeVille is now just a fond memory ....
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The bottom line best thing you can do to avoid head gasket damage is to keep your cooling system in top condition at all times! If your engine starts to run hot shut her down and find out the cause immediately!

I have had two cars that blew head gaskets within two weeks of overheating. I do not think that was a coincidence.
 

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White Diamond '03 DHS (with DTS floor shift)
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Just drain and refill the cooling system at least every 5 years with 50/50 DexCool and distilled water. Don't forget the cooling system suppliment (sealant tabs).
 
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