This is a cross post from Club GP (orignal poster is someone else) but plenty of LS4 folks are noticing their dex cool coolant appears brown like chocolate milk with <20,000 miles on their cars. There are some horror stories posted within the thread......anyone else experience this? Personally I might be taking a trip to the dealer and see what their "official" word is.

 

I heard this is just the nature of dexcool. It gets all clumpy. Why does GM still use it? Who knows? Anyone?

 

I thought it only does that if air is introduced into the system from too low of coolant?

 

I've got the crud in mine too...but the coolant is still orange'ish and liquidy. Car gets damn hot but the gauge never runs above 1/2.

 

No crud or clumps and 1/2 on the gauge collant still looks new.
In the GP it a few years old and still fine.

 

Dexcool is a good product if, if, if, if, if you do a flush every 20,000 or 2 years. Do not go by the 5/100000 mile thing from GM. Trust me, flush your car every 20k or every 2 years and it will thank you.

 

As a molecular design, Dexcool is quite old. GM keeps using updated versions for different purposes (I think we have Dexcool IV?) and it often reacts by getting really clumpy. Although I have some horror stories of it turning brown and hard as a rock, it usually just browns at the top of your coolant bottle.

 

Dexcool reacts poorly to air in the system. If properly maintained and flushed it's fine. Drive around on low tires for long enough and your tires will wear out and look crappy just like that guy's coolant in that image. It's all about how you maintain your vehicle.

 

Thats is the same way my GTO looked and my other GM products. Other were saying it was an additive the added to the dexcool. I dont know but I never had any cooling issues.

 

Thats not quite fair to say, 15,000 is way before any sort of necessary coolant flush.

 

I work for a Buick/GMC and it's common in all the cars...

Just about every overflow tank has this brown buildup due to air being present. most of the techs here pull the overflow tank off and hose them out when a car comes in for routine service.

 

I had the same looking stuff in my expansion tank also but also noticed that the water level was low. So I added some DISTILLED WATER!! From my dehumidifyer. Yes waster from a dehumidifyer is distilled water. Or you can by it. DO NOT USE WATER FROM YOU HOSE!!!!!
Dexcool hates it and it will add wear to your gaskets!!