Saw this on C6 and thought you all would like to read it! Enjoy, guys and gals!
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Some cars had considerable trouble that was traced to air leaks - mostly caused by the pressure cap.


Joint GM and Texaco Report:


"GM’s Jay Dankovich and Equilon Enterprises’ (Texaco) Stede Granger directed a 2-year study of thousands of DEX-COOL cooled vehicles. Armed with the results, they really didn’t have anything bad to say about the coolant. In fact, they strongly defended the product’s reputation. What they revealed to the audience is that specific models of GM vehicles have specific cooling system contamination problems. And essentially, that DEX-COOL is not the culprit!

What was said at the presentation? Besides the video, Jay and Stede included their personal observations about the study. At the end, they fielded several questions from the audience. Here’s a recap of their entire presentation:

1. Keep the cooling system filled. In fact, fill the reservoir bottle to “Hot” level when the system is cold. Problems arise when a system’s coolant level is not maintained. (Fleet vehicles receiving regular maintenance, and with reservoirs kept slightly above normal, do not show signs of contamination. This even applies to the specific “problem” vehicles.)

2. The coolant problems found in this survey were caused by system contamination, and not due to the breakdown of DEX-COOL.

3. Check and keep the pressure cap clean and functioning. A contaminated and/or malfunctioning cap causes low coolant levels, which in turn causes overheating and a greater loss of coolant: the notorious vicious cycle. No matter what the vehicle, if the cooling system acts suspiciously, test the pressure cap.

4. On the ST vehicle models mentioned in the GM DEX-COOL video, you “must” replace all suspect radiator caps, especially those with a Drop-Center design, with a Stant Model 10230 or 11230 (Spring-Center type). (Just do it.)

5. Make sure that the coolant is at a 50-50 mix. Often, the flush water was not being removed from the engine block. Consequently, when a 50-50 mix is added to the system the resultant mixture could approach 30-70. Like any fluid that has been diluted beyond its recommended levels, the lowered level of inhibitors will not be able to protect the coolant system effectively. Low levels of inhibitors can cause pitting on aluminum surfaces and general corrosion of cooling system metals.

6. A safe method of achieving a true 50-50 mix is to first determine the actual capacity of the system (use the owner’s manual). Then add 50% of “that” amount of undiluted DEX-COOL (or any coolant), and top it off with water.

7. Mixing a “green” coolant with DEX-COOL reduces the batch’s change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine. In order to change back to DEX-COOL however, the cooling system must first be thoroughly drained and flushed.

8. Bacteria cannot live in a hot, Ethylene Glycol environment and is therefore not a threat to DEX-COOL.

9. While there have been intake gasket failures on CK Series, V8 powered vehicles for various reasons, DEX-COOL has never been found as a cause.

10. Use a refractometer to check the condition of DEX-COOL. Its inhibitor package is strong enough that if the batch still provides proper freeze protection, it is probably still providing proper corrosion protection as well.

11. DEX-COOL can handle the minerals in hard water better than silicated conventional chemistry coolants. Drinkable water is suitable for top off.

12. In ST Blazer applications where the radiator cap is mounted at an angle to the ground, the vehicle is more susceptible to radiator cap contamination and its related problems. The Stant 10230 is a wise choice for these vehicles."

 

YEAH RIGHT... I dont buy anything Texaco or GM says about their evidence that proves how great DEXCOOL is for your car. Funny the GM spin always finds fault elsewhere but other manufacturers' customers do these same "other things" to their cars and never have a problem. Reason? THEY DON"T USE DexCool. My '95 Cadillac's DexCool was supposed to never need changing for at least FIVE years. After 4 years and 68,000 miles the head gaskets leaked and Cadillac said I needed to replace the motor. Now GM says flush and replace Dexcool every year or 24K miles.
I am only one of the thousands of people supporting the class action legal effort against Texaco and GM and we've heard this spin several times in the past.
Do a GOOGLE search on "Dexcool class action suit" or visit this link and get the the other side of the story:

http://www.consumeraffairs.com/autom...m_dexcool.html

ALSO, You should seriously consider replacing the DEXCOOL in your GM cars with another brand or have it flushed out of your car every 12 months or 18K miles.

 

Dexcool is

 

I don' even use Dexcool in my LS1. That's how much I hate that stuff.

 

Dexcool is the Asbestos of coolants. Junk.

 

I have 3 GM vehicles using Dex-Cool

1. 2001 Monte Carlo (115,000 miles)
2. 2000 Silverado (96,000 miles)
3. 1996 Corvette (82,000 miles)

Not a single issue with any of them. No sludge in coolant recovery tank.

Yes, I have heard about the class action lawsuite ZRWON pointed out. I agree there are thousands of people with issues. But on the other hand there are literally millions of these cars on the road with no issues too.

So, as with most everything else Your Mileage May Vary.

 

The best thing I have done in a long time is get that crap out of Camaro SS, and Silverado. I could not believe the sludge build up in my LS-1. I had everything flushed and went back to the proven 50-50 in all of my cars including my 89 coupe.

 

Often times, especially these days, the real problem is the car was not properly maintained or another problem occurred (like the radiator cap going bad) and the fix was delayed by an owner that was simply "too busy". We've become this crazed consumer culture that tolerates little inconvenience such as lifting the hood and checking fluids when we get gas. How often do you see anyone doing that at your local filling station these days? And when we fail to do our part (ie: maintain our cars by checking coolant levels) then we rush out and sue someone when the car fails prematurely. Ridiculous. I've had 3 cars with Dexcool and never had a problem. And these weren't low mileage cars either. . .Properly maintain your GM car and it will last as long as any Toyota or Honda.

 

I guarantee you there are '93 or '94 MY cars with the Northstar motor that came with conventional coolant from the factory that had a head gasket fail within 4 years or 68,000 miles as well. That sort of anecdotal evidence doesn't mean anything.

 

I've had several Chevys without problems. My 03 monte carlo had dexcool and it blew a gasket. I don't know if the evidence is anecdotal or not, but it cost me money. That's how I see it. And when I read up on the problem on various sites, I found out that I wasn't alone. Personally, I'd shy away from it. But that's my opinion and everyone is entitled to their own.

Matthew

Oh, btw, my car was properly maintained, so to me it wasn't an issue of neglect.

 

I don't think the general himself could have said it any better.

All it takes is one blown head gasket or a failed heater core and people seem to agree. Dexcool sucks!

 

The key problem causing these failures in the Northstar is failure to add and maintain the coolant additive. It is an organic sealant that comes in powder or tablet form and must be added to the coolant any time the system is opened (ie: to check or add coolant). A very common scenario is that the owner takes his car to Jiffy Lube or Instant Oil Change for the radiator flush and they flush it out and don't add the additive. The owner thinks he's performed the required maintenance and is totally unaware that the service was performed incorrectly.

 

I am two for three in the problem area.

2001 Grand Am problems at 30K
2003 GMC 2500HD problems at 4K
2002 Z06 no problem but will be changed shortly

Just do not trust the stuff, I now run Prestone yellow.