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Discussion Starter #1
I'm close to pulling the trigger on either a '02 or '04 Deville. Both have approx 55K on them and are in almost pristine condition. My question has (of course) to do with the Northstar reliability. After reading this forum and seeing the amount of failing head gaskets reported, I'm wondering if this model is even worth considering. Can someone confirm whether the 2000+ yr heads & gaskets been redesigned or not? I've seen two posts on '00 up failures with relatively low miles, few compared with the 90's vintage, but is it just a matter of time? I know the coolant should have been changed by now, but should it have something other than DexCool?
 

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1996 Cadillac Fleetwood Brougham
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In my Seville, I have been using normal coolant not Dex Cool .I think logic of it that neither Dex cool or extended life coolant thingy don't run to Northstar engine considering you will have to change the coolant no late than every 2 years .With the green or blue Castrol coolant change it 1-2 years .
I believer '03 and up Northstar engine yet to be reported bad headgasket .
I don't know but if I were you I'd pick up '04 DEville .
 

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White Diamond '03 DHS (with DTS floor shift)
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In 2000 they changed the head bolt length and thread pitch to make them more reliable, but there are no guarantees in life. Use Dex and change it at the required intervals or sooner.
 

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1996 Cadillac Fleetwood Brougham
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LOL, you know Dex Cool is said to change 5 years or 100 K miles ,right ? In other words it requires no maintenance or less maintenance to other stuffs However Northstar requires to change the coolant every 2 years or sooner .So if this is the case let's say you put a Dex in it and haven't changed it 5 years hence . What would happen ?
Most likely your heads would go bad ,this is very contradiction of what Dex cool says :alchi:
 

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The Northstar Tuner
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I am 100% sure you can do more damage changing the coolant than leaving it in!:rant2:
I can prove it 100%
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The coolant does not dissolve the head gaskets!!!!!!!:rant2:
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Come on guys. Just think about it. Coolant is not some magic solution.
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If you get an air bubble in the cooling system when performing a cooling system service you can over heat the engine and do more damage than the Magic Fluid ever could do. One hot cycle and if you add cold water or premix then you could really do it in.
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The only way to add coolant in a Northstar in MY opinion is to pull a Vacuum about 20"+, draw in the coolant premix, pull a Vacuum again about 25"+, Draw in the coolant again, You could do it one more time if needed. I have done it 3 times several times. Two times is all GM calls for.
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theory: Carbonation is held in soda pop under pressure. If the coolant has air in it or even microscopic air bubbles it can become trapped. If you release the cap on the soda the carbonation will come to the top. If you pull a vacuum it will lift the air to the top and the soda will be flat. The same goes for the air trapped in the cooling system. I pull a vacuum on master cylinders to get microscopic air out of the system. I do it to power steering systems also. It takes about 25 t0 30" before it really pulls out the fine air.
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If you leave air in the system that does more damage than coolant could ever do. I have a lot of Facts on this and the magic orange stuff. The way it is made out on this forum it is like battery acid.
 

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'93 STS (sold), now looking for a CTS Wagon soon!!
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Vacuum? I dropped a good/used North* in my '93 STS a year & a 1/2 ago.

My car has 130,000 miles and running great ( old engine had 121,000 - new replaced had 122,000 ). Please explain your coolant method?

Also, I found out ( upon removal ) that my tranny was rebuilt less than a year before I got the car. I suppose I should change the tranny fluid, but the coolant thing I'd like to hear about.

I believe in servicing the car, but "don't fix which is not broken".
 

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The Northstar Tuner
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Old fill proceedure
Cooling System Draining and Filling
Tools Required
J 26568 Coolant and Battery Tester

Draining Procedure
Caution: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

Remove the coolant pressure cap.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
Remove the front air deflector. Refer to Front Air Deflector Replacement in Body Front End.
Place a drain pan under the drain cock.
Open the radiator drain cock.
Drain the cooling system.
Remove the surge tank. Refer to Radiator Surge Tank Replacement .
7.1. Clean the outside of the surge tank.

7.2. Pour out any fluid.

7.3. Thoroughly clean the inside of the surge tank using soap and water.

7.4. Thoroughly flush the surge tank with clean water and drain.

Install the surge tank. Refer to Radiator Surge Tank Replacement .
Inspect the coolant condition.
Follow the appropriate procedure based on the condition of the coolant.

• Normal in appearance--Follow the filling procedure.

• Discolored--Follow the flush procedure. Refer to Flushing .

Filling Procedure
Notice: The procedure below must be followed. Improper coolant level could result in a low or high coolant level condition, causing engine damage.

Close the radiator drain cock.
Install the front air deflector. Refer to Front Air Deflector Replacement in Body Front End.
Lower the vehicle.
Important: Use a 50/50 mixture of DEX-COOL antifreeze and clean, drinkable water.

Slowly fill the cooling system with a 50/50 coolant mixture. Refer to Approximate Fluid Capacities in Maintenance and Lubrication.
Install the coolant pressure cap.
Start the engine.
Run the engine at 2,000-2,500 RPM until the engine reaches normal operating temperature.
Allow the engine to idle for 3 minutes.
Shut the engine OFF.
Allow the engine to cool.
Top off the coolant (1) as necessary.
Inspect the concentration of the engine coolant, using the J 26568 .
Rinse away any excess coolant from the engine and the engine compartment.

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Document ID# 1258545
2005 Cadillac DeVille
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http://www.fiero.nl/forum/Forum2/HTML/082514.html
more on the VAC-U-FILL
 

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White Diamond '03 DHS (with DTS floor shift)
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I am 100% sure you can do more damage changing the coolant than leaving it in!
Please tell me you are not suggesting that we don't change the coolant. It does loose it anti corrosion capabilities after a while.

This is the first time I have ever heard of pulling a vacuum in a cooling system. The Northstar is self purging as I think most systems are (assuming of coarse that the purge line is not clogged). I've never had a problem with air in the system.
 

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The Northstar Tuner
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Please tell me you are not suggesting that we don't change the coolant. It does loose it anti corrosion capabilities after a while.

This is the first time I have ever heard of pulling a vacuum in a cooling system. The Northstar is self purging as I think most systems are (assuming of coarse that the purge line is not clogged). I've never had a problem with air in the system.
It should be changed at normal service intervals.
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How could you get the air out?
how do you mix the water and coolant?
You don't shake the contanter to mix them together do you?
That would be like shaking a bottle of brake fluid and then adding it into the brake system.
The Vacuum lifts the air out of the system.
this is a picture of brake fluid
View attachment 33430
 

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White Diamond '03 DHS (with DTS floor shift)
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How could you get the air out?
I let the system purge itself like it is supposed to.

how do you mix the water and coolant?
I premix it. Yeah, I think I do shake it, but the bubbles come to the top long before I pour it in. I have never had a problem.

That would be like shaking a bottle of brake fluid and then adding it into the brake system.
Brake fluid I could understand, but coolant is a lot thinner than brake fluid.
 

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'93 STS (sold), now looking for a CTS Wagon soon!!
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Please tell me you are not suggesting that we don't change the coolant. It does loose it anti corrosion capabilities after a while.

This is the first time I have ever heard of pulling a vacuum in a cooling system. The Northstar is self purging as I think most systems are (assuming of coarse that the purge line is not clogged). I've never had a problem with air in the system.
I wanted to check out the vacuum method, but when I replaced my engine, there was not a drop of coolant.... I had no problem.

But thanks for letting me see what you were talking about.
 

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'93 STS (sold), now looking for a CTS Wagon soon!!
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About brake fluid...... I removed the dirty fluid at the top, pour in fresh fluid. and did what my motorcycle mechanic suggests...... Quickly pat the brake lever ( or peddle ) really fast, and watch the air pulse out of the return hole).
 

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I let the system purge itself like it is supposed to.


I premix it. Yeah, I think I do shake it, but the bubbles come to the top long before I pour it in. I have never had a problem.


Brake fluid I could understand, but coolant is a lot thinner than brake fluid.
The best car to watch it on is a Craptera. I will get a picture of a Deville. My point is that the air gets trapped in the coolant. If it take one high heat cycle to get it out. that can do more damage than 3 or 4 year old 36k coolant.
 

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LOL, you know Dex Cool is said to change 5 years or 100 K miles ,right ? In other words it requires no maintenance or less maintenance to other stuffs However Northstar requires to change the coolant every 2 years or sooner .
Where'd you read that? That is mis-information. Vehicles built in model year 1995 and prior required coolant changes every 2-3 years, filled with conventional coolant. Vehicles built in model year 1996 and later require coolant changes every 5 years or 100,000 miles, filled with Dexcool. The Northstar doesn't require a different (or shorter) coolant change interval than any other Dexcool-filled GM engine.

So if this is the case let's say you put a Dex in it and haven't changed it 5 years hence . What would happen ?
Most likely your heads would go bad ,this is very contradiction of what Dex cool says :alchi:
No, it's not a contradiction. The recommended service interval for Dexcool is 5 years or 100,000 miles. Your heads don't "go bad" when using Dexcool. At the furthest stretch of that argument, you could say that the coolant could use its anti-corrosion properties over time and natural processes would then start to eat away at the head gaskets. But that's the very POINT of Dexcool. It doesn't loose its anti-corrosion properties nearly as quick as conventional fluids. That's why you had to change conventional (green) coolant in 2-3 year intervals. Your engine would start to corrode otherwise. Dexcool doesn't require a change until 5 years, because its chemical composition is different from conventional chemicals. It's an OAT coolant -- Organic Acid Technology. Different from old green coolant.
 

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I had no problem with "trapped air" when changing my coolant or the coolant
in any other Northstar Cadillac. I've worked on MANY different cooling systems
in my 25 years as a technician and don't see the Cadillac system as difficult regarding trapped air.
The key is measuring the amount of coolant drained so you know how much will fill the sytem
back to where it was before draining it.
Then slowly filling the surge tank until you have replaced the entire amount.
If it doesn't take it all, let the car cool and usually the level will drop and it will take the rest.
Like Ranger said, make sure the purge line is clear if you have a problem.

Now I once replaced a cylinder liner in a Renault R5 turbo and after getting the
engine back together had a hell of a time bleeding that cooling system.
It's a rear/mid engine car with a front mounted radiator.
 

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Discussion Starter #18
:alchi: Holy crap. I just wanted to know whether the heads were different. Suffice it to say there is some debate about changing the coolant. I'm guessing the '03's up haven't showed up with blown gaskets because most don't have the mileage on them yet. Not sure whether I want to get involved in something that needs this much debate over what should be normal maintenance. :confused:
 

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White Diamond '03 DHS (with DTS floor shift)
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Don't let this discussion scare you. We are knit picking. The Northstar requires the same cooling system service as any other engine for the same reasons. Neglect them and they'll suffer the same consequences.
 

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Not sure whether I want to get involved in something that needs this much debate over what should be normal maintenance.
There SHOULDN'T be this much debate. It's all spelled out very simply in the owner's manual. There are those who chose to not follow the owner's manual, and there are those who do. That's all the debate is about.

Buy one of those used DeVilles with confidence. When I was looking for a car to replace my '97 (sold, not broke), I looked at various model years from 2000 to 2004. Not once did a question of head gaskets arise in my mind. I haven't looked back since. :thumbsup:
 
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