Have a new 07 coupe. GM says to use Dex Cool for the engine coolant, yet have read horror stories about alleged Dex Cool sludge problems. Do forum members use Dex Cool to top off the coolant reservoir -- or some other product?

Thanks

 

sludge prob. came form people mixxing green and red and using bad water...
also most sludge cars had other prob. like overheating....
rather than get them fixed they would put stop leak in the coolant...
so its a combination of many things..
use dex cool..
no problems....

udriveslow

 

 

Follow GM's directions to the letter for any car part/fluid and you won't (knock on wood) have a problem.

 

Dex-Cool. Using a coolant other than Dex-Cool could result in non-covered warranty claims involving any part of the coolant system.

 

 

 

Glen Looper in Rockville, MD. is true expert in automotive cooling system and has taken apart hundreds of Dexcool user's cars. Note his DexCool link on his webpage www.loopersc.com Some really nasty possib ilities

 

Here's my issue with the stories - for each one there are thousands of dexcool cars with no problems.

I have yet to see one expert, mechanic, or anyone else give a chemical or scientific reason as to why dexcool, which was developed specifically for aluminum engines, is causing problems. All we see or hear is circumstantial stories. There are many - including me - who have had dexcool cars for years, and followed the simple directions - clean potable water or dexcool only as additives - without problems.

So until I see some real evidence of why and how dexcool might do harm, I will stick with the manufacturer's recommendation.

Just my .02

 

No problems with Dexcool in my 96-
at last count that's 11 years old....

 

Thats my son name-Dex

 

Gel use to occur if the cooling system was low and there was lots of air in the system.

Gel does not occur if the vehicle is serviced/maintained properly. Also, I believe that Texaco reformulated Dex Cool.

 

I've been told that some of the alleged problems likely happened because the antifreeze was not drained and replaced with fresh antifreeze within a reasonable operating time period. When antifreeze loses its anti-corrosion properties, it can start eating away at metal.

 

Agree about the only problems might be if Dexcool is allowed to run low in a system. It may allow rust and gel in the iron block portions.

Keep the system serviced, that is topped up, correct level in the overflow container. There should be no problem.

And, as always, I don't think the majority of people that read this forum will go to 100,000 miles before changing their antifreeze.

I think 3 years or 50,000 miles, which ever comes first, would be a good, extremely conservative time period for changes.

 

Appears to be a complex topic with many facets:

"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.

Left: Drop-center, “vented” radiator pressure cap. GM found this cap (like the Stant 10231) to be less helpful than a Spring-center cap (shown below) in controlling the formation of contaminants in the cooling system. If contamination forms, the debris fouls the valve and restricts its ability to seal. In turn, the coolant boils at a lower temperature. Coolant loss is accelerated and so is the accumulation of contaminants.

Left: Spring-center, sealed radiator pressure cap (like the Stant 10230). This is the preferred cap for GM applications that are more prone to accumulating cooling system contaminants.

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."

See http://www.imcool.com/articles/antif...l-macs2001.htm for pictures.

 

I have had four GM cars with DexCoo and have no problems;

98 Grand Prix GT 125K, flushed at 5YRS
00 Intrigue 80K, Flushed at 5YRS
04 Grand Prix GTP 30K

I have not heard any horror stories from actual owners of DeCool cars.
Frank

 

Then he mist be

 

I think a little research will help answer this. I get fustrated when I hear things like, "I heard", "I read", "Someone told me" etc.
The problem is someone may of had a problem and they were the problem and blamed it on the product rather then come clean with their mistake.
Last, If it is such a problem why would a big corporation like GM turn a blind eye to it?????? Its only going to cost them money to fix it.
I think we need a scoop research and a dash of common sense here.
Okay I am on a roll, I always ask someone that gives me information that attacks a product this question, where did you get the info and can it be verified!
Okay, I'm done!

 

YOU BELIEVE WHAT A SHADE TREE MECHANIC OVER A GM WORLD CLASS CERTIFIED, AUTO AND DIESEL ASE MASTER CERTIFIED TECH THAT HAS WORKED ON HUNDREDS OF DEX COOL VEH. PER WEEK.......

DO ME A FAVOR AND TOP OFF YOUR COOLANT WITH GREEN..
ITS WAY BETER THAN RED....BECAUSE GM DOESNT KNOW WHAT THEY ARE TALKING ABOUT...




LET ME KNOW HOW THAT WORKS OUT FOR YOU......









UDRIVESLOW

 

I always appreciate the comments from forum users on any vette-related topic. I originally posed the question because of numerous web postings about alleged Dex-Cool issues and related litigation against GM from car owners with charges and claims of cooling system problems. Since my 07 is a huge investment, I want to ensure I'm always doing the right thing.