DexCool antifreeze forms sludge on Chevrolet Impala

Problem Description

(30 people reported this problem)

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Viewing 1-17 of 17 comments
2003 Chevrolet Impala - 3.4L V6 100,000 mi,
Same sludge. I didn't know what it was so I flushed the system, replaced a couple hoses a refilled with new Dexcool. The sludge continued to reappear. I have flushed again. I didn't know this may be related to the Dexcool until reading this site. The car now has close to 130,000 miles. I replaced the thermostat which fixed an overheating problem, but the thermostat may have failed due to sludge build up. My heater core does not work properly and I'm about to replace that. I also went and purchased a new radiator being that if there's sludge everywhere else it probably ruined the radiator also. Is my engine ruined? Do I have recourse against GM? I don't know.

Discovered brown sludge in neck of radiator fill port while doing routine check and maintenance. Obviously going to have more sludge down in the engine as the car now has 135,000+ miles on it. Don't mind doing a flush, or even two, but what can I use to clean this sludge, or do I even WANT to? Perhaps if I clean the sludge out, who knows what leaks may suddenly appear. If I can get it good and clean, with no side effects, I'd go back with good old green stuff, but local Walmart doesn't even carry the green stuff anymore. All they have is the "works with any color antifreeze" version. I'm not sure what's in that stuff. It does not say Dexcool anywhere, but I have to wonder what it is that's in the bottle.

2003 Chevrolet Impala - 3.8L V6 178,342 mi,
I just bought this 2003 impala 3800 series 2 and it had a random miss fire. So needless to say I changed spark plugs and wires car runs like a champ. But as the car got hotter I noticed my fans weren't cutting on so by luck I decide to check the radiator and nothing but sludge brown like mud and thick. Anybody best steps from here???

2010 Chevrolet Impala - 3.4L V6 113,000 mi,
I have a 2010 impala with a 3.5 v6 and had a code for a coolant thermostat. Replace the thermostat and filled coolant and now overheats. Whats the issue?

2003 Chevrolet Impala - 3.8L V6 224,878 mi,
Car started over heating unexpectedly and trying to see what's the problem

2003 Chevrolet Impala - 3.4L V6 86,929 mi,
Getting hot lot of sludge build up on radiatior cap replaced water pump previous and flushed system still gets hot

2003 Chevrolet Impala - 3.8L V6 50,000 mi,
Not yet fixed. Brown sludge in the radiator which is causing the heater to stop working and the engine temp starts to jump around a lot.

I just discovered white slime on the underside of my 2003 Buick Century radiator cap and radiator filler neck. I think this is uniquely a GM DexCool problem because I have never seen this slime in any of the many non GM cars I've owned in the past. I flushed the cooling system 6 months ago with equal parts DexCool and distilled water so i shouldnt be having any problem like this. I know GM has settled lawsuits in the past over there DexCool 100,000 mile recommendation causing peoples engines to fail but if theres still a problem with DexCool they need to change their formula.

2003 Chevrolet Impala - 3.8L V6 77,000 mi,
I took my car to the dealership where I've been buying my cars, and having them do maintainence and service work. They told me that the price they quoted me includes a flush, replace a radiator hose and the sepentine belt. It cost $760.00! They advised me to have a radiator flush soon, unfortunately, they did'nt tell me that sludge was building up and more problems would be forthcoming. The second time I took it in they quoted the repair at $500.00. I asked why this new leak they found was'nt seen during my first visit. The advisor told me it is brand new! I just found out that there's sludge in my radiator because I inspected it yesterday! Now, I'm in the process of finding a reputable auto mechanic in my area, which is tough. I'll update this as soon as the problem is fixed. Thank you.

2006 Chevrolet Impala - 3.4L V6 91,602 mi,
I just notice this brown like sludge today. Was doing a fluid inspection on my car today as I usually do every couple month or so. At 1st I though it was clay until I touched it and it was nice and soft. This sight said around 100,000 miles mine just has 91,000. Tomorrow I'm planning to do a full radiator system flush including the heater coil. I'll update in a month or so to let you guys know if it ce up again.

Black sludge in coolant resiviour also over heats after about ten minutes.

2003 Chevrolet Impala - 3.4L V6 45,000 mi,
DexCool antifreeze formed brown gel-like sludge, first observed at radiator cap. Supposed to last 100,000 miles. Lawsuit settled for cases where engine failed. Flushed system and replaced coolant. Keep air out of system by ensuring coolant reservoir always at proper level and check radiator periodically by removing cap.

Kept on flushing radiator with cleaner putting more coolant. So far hasn't appeared again. First replaced radiator.

2004 Chevrolet Impala - 3.4L V6 100,000 mi,
I am not sure how this can be fixed other than that I am having to have work done to my car and replace a lot of parts that are damaged by the Dexcool turning to sludge. I have had to replace the heater core, water pump, and have had the engine flushed around 4 times. Now, I am being told I need to have the Accessory Belt Tensioner and Serpentine Belt replaced as well as the Power Steering Pump, Radiator Cap, and Thermostat. GE should come up for a fix to this happening in their Chevy vehicles!

I just took my car to Firestone because of no heat. They said the Dexcoolant in the radiator had turned to sludge. They refused to remove it and suggested I go to a dealer.

2004 Chevrolet Impala - 3.8L V6 95,880 mi,
Intake manifold began to leak. During the repair, Dexcool sludge was discovered as the cause - eating away the gasket and pitting the manifold. A "universal" high performance coolant was used in place of Dexcool upon completion of the repair.

2004 Chevrolet Impala - 3.8L V6 162,000 mi,
I bought the car with 159k miles and after a month or so I was going through everything on the car and noticed the brown sludge in the radiator. Sorry, long story not so was a leaking transmission cooler line that was internal to the radiator tank just below the radiator cap. Before I replaced the radiator, I flushed the transmission, then replaced the radiator. With new radiator installed, I flushed the cooling system to get rid of the sludge in the cooling passages in the engine. It was a little unorthodoxed but it worked! I poured a couple scoops of Tide powdered laundry detergent in the radiator and filled with straight water. Installed the cap and ran it at normal operating temperature for about 30 minutes. Drained the system and did it a second time. Then I connected a flush kit that connects inline to the heater core, connected a garden hose, removed the radiator cap, turned on the water and started the engine and let it run at normal operating temperature again and let it go until completely clear water (no soap bubbles) came out of the radiator filler neck. I then drained the water and refilled with regular green ethylene glycol antifreeze. I also replaced the overflow tank because it was full of sludge also.
Note: Additionally, this car also had a slight shudder in the transmission that was most noticeable during acceleration and deceleration. Once I replaced the radiator the shudder went away, presumably caused by the constant loss of pressure in the valve body in the transmission. Hope this is helpful!