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hi ive been a memeber here for a little while but lurked for months . Well i have a 2000 base deville and i love it . But i developed an overheating problem one day after i washed the engine and then got the car washed . About 10 min after i got out of the car wash it overheated . I thought i just got a sensor wet but not the case. I had a blown headgasket and after a lot of thinking i decided to go through with it . I had a gm dealer do it who has done about 6-10 other headgasket jobs on the n*. Well they did the head gasket and it still overheated . They didnt magnaflux the heads or block but check the heads for being flat and i guess were fine. Well they thought they had air in the system or maybe they did . But they tried things and still over heating . SO they check further and found the waterpump to be weaping and they said we will fix that and that must be where the air is coming in . Welp they changed it and same thing . So out of ideas they had the radiator flushed thursday , and installed it friday . They got some crap out of it but nothing the guy who flushed it thought it would cause a car to overheat. O and btw the week before when they gave it back to us since they thought they fixed it they let it sit and run for 3 hrs and no overheating . and then that night after we paid for it it overheated. So up to current they radiator they run it saturday and its fine and then monday morning and its fine , monday afternoon it overheats again .

Now this car has been checked for compression and it passes. it also passes the coolant leakdown test too . And they also analyzed the exhaust and no water it in. Normal reading . SO now they are stumped and like want me to tell them what to do with it . when i had this done they said they warrantee it for 12 months or 12000 miles. And i allready paid for it .

so has anyone else had this many probs with it . now i also cant believe that the car would crack a head or something since these cars have camel mode and can run with no coolant in them . But do you guys think its a crakced head or air still in the system .

I mean it can run for hrs idle and not overheat but then overheat when driving . Im sorry if i missed anything but this makes me mad this subject since ive allready spend 2500 and havent had my car for over a month and a half.

So what should i do , anyone ever heard of this many probs.
 

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1996 Deville (sold), 2000 Mustang GT
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That is a very strange situation, very strange.

It may sound dumb but did they do both headgaskets? ANother member had a caddy dealer only replace one of the headgaskets, only to have to tear the motor down a second time to do the other.

Second question is did they timesert the block when they repaired the headgaskets? THe reason most n* headgaskets fail is because the headbolt threads pull out of the block. The timesert kit replaces the threads with bigger ones that won't back out. I know they did the tests for a headgasket but its possible that when they torqued done the head the bolts backed out since the threads were bad. Find out from the dealer exactly what they did with the threads in the block.

Other than that maybe a bad thermostat? Or something more serious like a warped head or cracked. You will be suprised at how much stuff a dealer lets slip by. It may be time for a second opinion. Just very strange.
 

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The Northstar Tuner
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That is a very strange situation, very strange.

My first question is did they timesert the block when they repaired the headgaskets? THe reason most n* headgaskets fail is because the headbolt threads pull out of the block. The timesert kit replaces the threads with bigger ones that won't back out. I know they did the tests for a headgasket but its possible that when they torqued done the head the bolts backed out since the threads were bad. Find out from the dealer exactly what they did with the threads in the block.

Other than that maybe a bad thermostat? Or something more serious like a warped head or cracked. You will be suprised at how much stuff a dealer lets slip by. It may be time for a second opinion. Just very strange.

You have NO clue on what a TIMESERT IS!!!!!
I am not impressed by Timesert Insterts for Northstar head bolts!
I have installed a hundred or so, but I have installed them all but 1 on 99 and prior blocks. I have passed on several block that would never hold a Timesert. The block are just too badly deteriorated on the 99 and prior to hold Timesert inserts MOST of the times.
A Timesert insert just makes the bolt bigger. It is not a permanent part of the block. You put the little piece of crap in the block. Then you heat the block and it expands leaving the insert loose. Just like if you heat a rusted nut.


Pitted 99 block Before cleaning
2.jpg
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Pick in a hole after it has been drilled for a timesert
3.jpg
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Pit after hole has been drilled
5.jpg
4.jpg

hi ive been a memeber here for a little while but lurked for months . Well i have a 2000 base deville and i love it . But i developed an overheating problem one day after i washed the engine and then got the car washed . About 10 min after i got out of the car wash it overheated . I thought i just got a sensor wet but not the case. I had a blown headgasket and after a lot of thinking i decided to go through with it . I had a gm dealer do it who has done about 6-10 other headgasket jobs on the n*. Well they did the head gasket and it still overheated . They didnt magnaflux the heads or block but check the heads for being flat and i guess were fine. Well they thought they had air in the system or maybe they did . But they tried things and still over heating . SO they check further and found the waterpump to be weaping and they said we will fix that and that must be where the air is coming in . Welp they changed it and same thing . So out of ideas they had the radiator flushed thursday , and installed it friday . They got some crap out of it but nothing the guy who flushed it thought it would cause a car to overheat. O and btw the week before when they gave it back to us since they thought they fixed it they let it sit and run for 3 hrs and no overheating . and then that night after we paid for it it overheated. So up to current they radiator they run it saturday and its fine and then monday morning and its fine , monday afternoon it overheats again .

Now this car has been checked for compression and it passes. it also passes the coolant leakdown test too . And they also analyzed the exhaust and no water it in. Normal reading . SO now they are stumped and like want me to tell them what to do with it . when i had this done they said they warrantee it for 12 months or 12000 miles. And i allready paid for it .

so has anyone else had this many probs with it . now i also cant believe that the car would crack a head or something since these cars have camel mode and can run with no coolant in them . But do you guys think its a crakced head or air still in the system .

I mean it can run for hrs idle and not overheat but then overheat when driving . Im sorry if i missed anything but this makes me mad this subject since ive allready spend 2500 and havent had my car for over a month and a half.

So what should i do , anyone ever heard of this many probs.
I have never seen a cracked head.
Find out if the dealer is using this tool Vac-N-Fill (GE-47716)
This is a required tool and they must have it. They may not have used it, but they should use it on a Northstar.

If they use this tool and remove all the air from the system with this tool and then the air come back it has a Combustion Camber leak into the cooling system!
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Tool info http://216.182.211.32/techlink/images/issues/feb06/TLFeb06e.html#story1

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It is possible that they did not clean the head bolt holes properly and stack the sealer. This will cause the threads to break out of the block. Also the block has an air dam built at the top of the cylinder liners. It protects the the head gasket. The dealer may have removed it by mistake.
Air dam
1.jpg
 

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Is it losing coolant?

Does it overheat in every driving situation or only at certain times? Hills/mountains, heavy traffic, cruising on flat highway,suburban driving?

Stop at a radiator shop and have them do an exhaust gas test on the coolant.
 

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Discussion Starter #5
they did both headgaskets and they did not use timecerts . They said they have done some and not all of them needed it .

My father and i went up last night to talk with them and they are gonna take the engine back out and send the heads out to check them , get them magna fluxed .

? why would they need to timecert the block if all the bolts torque down ? Wont it be fine .

It isnt loosing coolant either it usually overheats when they get to a hill or something but it doesnt cool down . I just dont understand how it could eb fine for like a day or two and then screw up .

they also replaced the thermostat , and the surge tank cap .
 

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Really sounds like a shoddy repair, especially since every other part of the cooling system has been replaced and you are still experiencing problems. You may be better off cutting your losses and replacing the engine or wait till the dealer gets the headgaskets repaired correctly. Although its weird that it isn't losing coolant.
 

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The Northstar Tuner
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Really sounds like a shoddy repair, especially since every other part of the cooling system has been replaced and you are still experiencing problems. You may be better off cutting your losses and replacing the engine or wait till the dealer gets the headgaskets repaired correctly. Although its weird that it isn't losing coolant.
This is an 00 not a 99 and prior. The material used in the block casting was redisigned for 00. It has a better blend. I have not seen an 00+ that could not take a Timesert.
 

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they did both headgaskets and they did not use timecerts . They said they have done some and not all of them needed it .

My father and i went up last night to talk with them and they are gonna take the engine back out and send the heads out to check them , get them magna fluxed .

? why would they need to timecert the block if all the bolts torque down ? Wont it be fine .

It isnt loosing coolant either it usually overheats when they get to a hill or something but it doesnt cool down . I just dont understand how it could eb fine for like a day or two and then screw up .

they also replaced the thermostat , and the surge tank cap .
Magna Flux inspection involves magnetizing the part to be inspected and covering it with a petroleum solution containing fine magnetic particles which are attracted to the magnetic field disruption caused by a crack. The cylinder heads are made from aluminum and are non-magnetic. Somebody there is full of crap. Crack inspection of aluminum alloy parts involves cleaning the part and applying a dye penetrant solution which is then rinsed off. A dry powder is applied to the part which draws the dye from a crack showing the location of the crack. Things don't sound very good about the shop that is doing your work. If what you have told us is accurate they are totally unqualified.
 

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they did both head gaskets and they did not use timecerts .
It isnt loosing coolant either it usually overheats when they get to a hill
It's the head gaskets. If they had Timeserted all 20, you would not be having this problem. Kind of add to Koz's statement. They are unqualified.
 

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Agreed, the dealer should have timeserted the block. Of course, if the factory timeserted the blocks to begin with, the Northstars wouldn't have the terrible reputation for unreliability they have earned, and GM wouldn't have lost so many loyal customers.
 

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Agreed, the dealer should have timeserted the block. Of course, if the factory timeserted the blocks to begin with, the Northstars wouldn't have the terrible reputation for unreliability they have earned, and GM wouldn't have lost so many loyal customers.
How terrible "Really" is the reputation. When it comes down to it the N# is one fine engine.
 

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... Of course, if the factory timeserted the blocks to begin with, the Northstars wouldn't have the terrible reputation for unreliability they have earned, and GM wouldn't have lost so many loyal customers.
This would be a good topic for a new thread. I'll bet a cost-benefit analysis was done and someone got a promotion for the cost savings of NOT using inserts at the factory. This is the problem with the domestic auto-makers; short-term thinking. I’m sure the failing head gaskets are doing more damage to customer loyalty than can be accurately measured. The word gets around at the golf courses and country clubs.
 

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Its got a lot to do with the headbolts pulling out. But my mechanic thinks its that gm/cadillac used a very cheap aluminum (hence too soft) for the engine block. I am not sure how much truth there is to it, but it would make sense.
 

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Its got a lot to do with the headbolts pulling out. But my mechanic thinks its that gm/cadillac used a very cheap aluminum (hence too soft) for the engine block. I am not sure how much truth there is to it, but it would make sense.
AJ has eluded to that. I believe he said the 2000+ are better.
 

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I would say they did not have to timesert the engine at the factory, but adding larger/longer bolts and stressing the coolant change at 5 years probably would have eliminated 90% of the HG problems.
 

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Those poor little aluminum threads never stood a chance. They are just overstressed. They are only about 7/16 inch diameter and pretty fine. The bolts are grade 8+ hardened steel and torqued to over 95 lb-ft! It really became clear to me when I torqued my head bolts down. I had a two foot long torque wrench and was busting a nut getting to the required angle. I just kept thinking that there is no way aluminum threads could ever handle this (I had just installed the Norm's "boat anchor" inserts so I wasn't worried.)
 

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I would not waste my time with the current shop, nor with the current head bolts from GM. As the bolts do work from GM, a better solution is to insert all 20 holes with Norms inserts and use the ARP stud kit for Audi/Volkswagon. Your torque value is 65ft lbs for aluminum heads.

Gm techs can whine all they want, but the results when done as suggested, are less prone to repeat failure. You can look up my prior write up on this subject.


MAK
 

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Those poor little aluminum threads never stood a chance. They are just overstressed. They are only about 7/16 inch diameter and pretty fine. The bolts are grade 8+ hardened steel and torqued to over 95 lb-ft! It really became clear to me when I torqued my head bolts down. I had a two foot long torque wrench and was busting a nut getting to the required angle. I just kept thinking that there is no way aluminum threads could ever handle this (I had just installed the Norm's "boat anchor" inserts so I wasn't worried.)
I like his inserts. I just have used them both and can see the best of both worlds. On a 99 and prior norms is the best way to go. I wish the tooling was more like timeserts.
 
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