2yrs for dexcool is some seriouse PM.. if your dexcool is turning brown it is mixing with something.. Green coolant, stop leak additives, or oil are the 3 main ingredients that turns dexcool brown.

 

Actually, it is low coolant level that is the main cause of the sludge issue. It's a problem GM has been trying to address ever since they spec'd the stuff from Havoline. With your stated automotive experience, I'm suprised you aren't somewhat familiar with that fact??

GM recently paid over $30 million to settle outstanding lawsuits against them due to Dexcool failures. I believe it was over 40,000 claims.

The simple fact is while most newer GM/Dexcool vehicles make the 5 year mark with no issues, some still do not. The easy and inexpensive way to avoid the problem is to simply change it every 2 years like any other coolant.

Here's what to expect when the coolant goes bad:

Dexcool Pictures

Dex-cool Contamination

 

carloscrx, I for one would like to see the pix of the rad you cut apart. I haven't cut an H3/H3T rad in half to see the internals. It would be very interesting to see.

 

Yes I will post the pics I was goin to make myself an all aluminum rad. But when I see the transmission cooler is aluminum I just change my mind I think it would be very hard to find a cooler like that and my point of view is not worth it making an aluminum rad un less u have turbo or supercharge .if my new rad last for 50000 mi. ill be happy,ill post pics later so u see is really well made .

 

To Hummerz credit, i have talked to several dealerships who have seen this before. All of them can tell you what happened but none of them can tell you why! I have also been unable to find the cause in the research I have done. The two possible causes given by Hummerz are two I have come across. Again, anyone can tell you what happened and the simple fact that in all of the cases I have found, nobody has been able to provide the cause. I personally don't care where the info came from and I want to thank Hummerz for sharing it as this has been bugging the **** out of me. The potential causes you have given do make sense and I am curious which is more probable. My curiosity is in the rate of corrosion between the two and the manner in which it corrodes. Corrosion resulting from improper PH levels means it is likely that the acidity is uniform throughout the system. In the process of Electrolytic corrosion, do you know if it is uniform as well? It seems to me that due to current involved, it may attack aluminum in concentrated areas such as a joint or surface scratch. Anyway, I appreciate any info anyone can provide that will lead me to the cause so if you have answers please share the info.

 

Pics are up..

 

Wow, I have seen dexcool coolant in vehicles looking like that(rusted color), however there were other problems: original coolant in a 10+- yr old car, leaking intake manifold, blown head gasket,...
Coolant only goes low for 1 reason: Leak...
I was stating that if your coolant turned brown within 2yrs, there is another problem. CONTAMINATION!
I would change the dexcool in my vehicle if it was discolored, and before 5yrs...
Preventative Maintenance is the KEY!

 

Dexcool has a lower akaline level than traditional green coolant. The higher alkalinity levels of green coolant lead to harmful corrosion in aluminum engines and are the reason why Dexcool was developed.

The issues with the sludge formation in Dexcool have been reported in some nearly new vehicles with less than a year and less than 10k miles on them. The PH levels of the coolant weren't an issue, but the coolant level often was. The key factor in sludge formation is when a Dexcool vehicle's coolant sytem has not been properly filled when new, or inproperly flushed/refilled at some point and as a result, air pockets become present in the cooling system which can lead to corosion of some exposed non-aluminum components which corrode at a faster pace due to the lower alkalinity level of Dexcool.
Dexcool is good for protecting aluminum, but not as good as regular coolant at protecting other metal components.

Those exposed corrosive areas then keep on churning out sludge particles which settle in various nooks and cranies and at the bottom of the radiator as I pictured in my earlier post.
The sludge then creates an even higher pressure environment in the cooling syetem which causes seal leaks and wear to the water pump.

The keys to maintaining a clean Dexcool system are:
A) Don't let the coolant level fall below normal and if it does, properly flush and refill the system to remove any air pockets.
B) Change the Dexcool regularly. It is not that expensive or time consuming and 2 year changing is cheap insurance against the known problems of Dexcool.
If kept full and fresh, it'll do it's job just fine.