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2007 Cadillac STS-V Black On Black
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Discussion Starter #1
I know our owners manual recommends the use of DEX-COOL with a 50/50 mix but I've been reading up on it and have found some concerning info. Apparently it causes corrosion and other internal junk buildup - http://www.consumeraffairs.com/news04/2006/08/gm_dexcool.html

Some discussion on another forum - http://www.g6performance.com/forum/showthread.php?t=12484

Anyone have any such issues?

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It looks like GM is aware of that fact that this stuff shouldn't be in the vehicle for more than 5 years or 150000 Km's. I have no idea when/if the coolant was ever changed in my car but I hope it was. I'm definitely going to do a coolant flush & change asap but I'm not sure if I should convert to the green stuff or not. Maybe I'll see what the old coolant looks like first.
 

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2007 STS-V, 2007 Escalade, 2003 Escalade EXT, 2014 ELR
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I've been using Dex-Cool since my 96 Vette came with it from the factory, I've never had any issues with it but I do maintenance on schedule.

I had a friend who is a GM tech and asked him about this several years ago. He did tell me that he saw some pretty bad engines from Dex but the common theme was those engines were running an open system leak and were constantly drawing air into the system through a leak for an extended period of time. Those systems seemed to gunk/gel up. He never saw those issues on a cooling system that was in good shape.
 

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2007 Cadillac STS-V Black On Black
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Discussion Starter #3
I've been using Dex-Cool since my 96 Vette came with it from the factory, I've never had any issues with it but I do maintenance on schedule.

I had a friend who is a GM tech and asked him about this several years ago. He did tell me that he saw some pretty bad engines from Dex but the common theme was those engines were running an open system leak and were constantly drawing air into the system through a leak for an extended period of time. Those systems seemed to gunk/gel up. He never saw those issues on a cooling system that was in good shape.
Alright well that's good to know. As far as I know there's no leaks in my car (fingers crossed it stays that way) so as long as I get it flushed & changed asap and then change it whenever needed, i should be good.
 

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2006 STS-V, 2004 Pontiac GTO, 2008 Pontiac G8 GT, 1999 Chevrolet Suburban LT 4x4
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This is nothing new and has been an age old argument. A lot of 3800 owners squak about it too as 3800's were prone to issues with the UIM and LIM gaskets.

I'm a former GM tech. As long as you maintain your cooling system with routine checks and/or draining flushing, you will be 110% fine. You could have the same issue with an old school Ethylene-Glycol (green) coolant too, if left unmaintained.

The issue is in part the long or extended maintenance interval that DexCool is supposed to provide. Much like many other things under the hood, it's meant to last 100,000 - 150,000 miles. In most people's cases, that much mileage gets amassed over 5+ years. So add that amount of mileage, over a long period of time, and the general automotive consumers propensity to put off normal routine maintenance, THIS is when issues most likely come up with DexCool.

In some cases it's a case of which came first... The chicken or the egg! The "gunking" up comes from air intrusion into the fluid. In a properly operating cooling system, it is sealed, purges air, and will operate in a small amount of PSI. So if air is getting in, there is a breach somewhere. Faulty radiator cap, overflow tank cap, gasket failure, leaking hose, etc... In the case of the 3800, the faulty UIM/LIM gaskets. Then again, add on that the average consumer doesn't do preventative maintenance on their vehicle, this only exxagerates the issue. So by the time the failure is well known, it's wayyyy too late.

Again, never had a vehicle that had been properly maintained come in with an issue. Never myself as a mechanic, have I had an issue (but again, I drain/flush all mine on a regular basis, so typically my coolant is as fresh as my oil). It was always it was those that looked like they went through a war zone and never once had their cooling system checked in 5 years/100k that had problems.

FWIW, Chrysler (and a few others, I think ford is one), that uses a slightly modified version of GM's Dexcool called G-05. GM's DexCool is an "OAT" coolant. That stands for "Organic Acid Technology". G-05 is called a "HOAT" coolant or "Hybrid Organic Acid Technology". It too doesn't have ANY issues if you properly maintain it through the life of the vehicle as you own it.
 
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