oil(?) in coolant reservoir

[Firebirdjones]

I've never had a problem with Dexcool,,,,but I never leave it in there for the 5 year service intervals they recommend either. I change it every year just like any other antifreeze.

The corrosion you speak of happens with the regular antifreeze as well if left in the system too long. I've seen the brown sludge in the older cars as well that use standard antifreeze.
It all boils down to poor maintainance.

[99RTA]

I have to disagree...NOTHING EATS LIKE DEXCOOL! I've seen systems TOTALLY destroyed, i'm talking so much damage its hard to believe. I think GM was smart going to it for their dealers sake of filling their pockets with repair money. But it bit them in the butt. Dexcool is without a doubt one of the worst products of all time. I can't think of any other automotive product that has caused so much damage. What suprises me is people who never had trouble with it tempting fate when there are MILLIONS of damage claims out there over it.

[shady milkman]

omggggwwaaadddd....its nothing to worry about..my dipstick is/was nasty...its from moisture ..if you realize that its all over the coolant stick..much higher then the coolant level...i bet you do alot of short trips dont you ?? its a nasty brown on the stick from the moisture not being burnt off ..that will happen when you mostly go to op temp

[Firebirdjones]

I have to disagree...NOTHING EATS LIKE DEXCOOL! I've seen systems TOTALLY destroyed, i'm talking so much damage its hard to believe. I think GM was smart going to it for their dealers sake of filling their pockets with repair money. But it bit them in the butt. Dexcool is without a doubt one of the worst products of all time. I can't think of any other automotive product that has caused so much damage. What suprises me is people who never had trouble with it tempting fate when there are MILLIONS of damage claims out there over it.

I don't think anyone is depriving you of your opinion. I'm just not that convinced, seeing as how I've had 4 vehicles with it,,,,currently have 3 in the stable with it,,,and I just don't have a problem with it in any vehicle.
I also have 7 other cars that use plain old green antifreeze and they too will get the same ole brown goop in them if they aren't serviced regularly. So I don't blame it soley on the brand or type of antifreeze.
In my experience I see it as not being routinely tested and changed no matter what you use.

[Firebirdjones]

What suprises me is people who never had trouble with it tempting fate when there are MILLIONS of damage claims out there over it.

You know what I see in that statement??? Millions of people that don't service their cars. I see it all the time. It's amazing how people treat their automobiles. As long as it runs I just fill it with gas Some people just don't know how, but most just don't care to do it or don't want to spend the money.
Antifreeze ranks right up at the top as one of the most ignored services on a car, right up there with brake fluid. I've seen 10 year old cars that have never had it changed.
When GM came out with a 5 year antifreeze it was a mistake in that it made people think they could ignore it for years. Bad move.
Test any antifreeze with in 12 months of a fresh change and you would be surprised how acidic they become.
Mixing with tap water and/or flushing with tap water does not help matters either.

[rbob93]

My car has lived on DexCool since new.
I change it every spring......system is like new.

[99RTA]

My car has lived on DexCool since new.
I change it every spring......system is like new.

Well thats cost effective! Why would you want any coolant in there that needs to be changed EVERY YEAR and could start eatting your engine?

[99RTA]

omggggwwaaadddd....its nothing to worry about..my dipstick is/was nasty...its from moisture ..if you realize that its all over the coolant stick..much higher then the coolant level...i bet you do alot of short trips dont you ?? its a nasty brown on the stick from the moisture not being burnt off ..that will happen when you mostly go to op temp

Now there is well informed opinion....he must work for a dealer!

[Wesman]

Well thats cost effective! Why would you want any coolant in there that needs to be changed EVERY YEAR and could start eatting your engine?

Dexcool itself doesn't eat anything. Its not corrosive, nor damaging to metal. However, It can sludge up when left in the cooling system too long.

GM isn't the only one to use dexcool. Many other manufacturers use variants of Dexcool that are basically the same forumla, but dyed a different color and with a different name on the bottle.

[shady milkman]

Now there is well informed opinion....he must work for a dealer!

not quite ..i rarely go to the dealership..but good try..i was informed by several mechanics that is the reason....same with your oil fill cap..will have that milky shit on the bottom sometimes if you dont let your car get to op temp to burn off the moisture

[99RTA]

Dexcool itself doesn't eat anything. Its not corrosive, nor damaging to metal. However, It can sludge up when left in the cooling system too long.

GM isn't the only one to use dexcool. Many other manufacturers use variants of Dexcool that are basically the same forumla, but dyed a different color and with a different name on the bottle.

dexcool turns into an extremely strong acid.......better read up junior.

[Tbenton01]

Have a problem that seems to even baffle the local mechanics I talk to on this. Hope someone out there has an idea. Earlier this spring, had a mechanic notice an oily sludge, mixed in with the coolant on the dipstick going into the coolant reservoir. Had the coolant changed, to flush the crap out. Was fine through this summer, but when I checked the coolant dipstick, a week ago, I noticed the same sludge.
Weird thing is, it only seems to be in the reservoir (fill) tank, but if you pop the radiator cap next to it, the coolant is completely clean. Mentioned this to another mechanic and he thought it could be a blown head gasket. Thing is, the car runs and idles great, their are no leaks in antifreeze or oil (on the ground), no overheating problems, and starts up fine everytime. Only issue I can think is that sometimes I'll get a loud "pop" coming from the exhaust. Usually just when I give it alot of gas, shifting through gears. This only happens at initial startups, and immediately goes away. Not sure if that's just the way the exhaust is (SLP "loudmouth") or backfiring. Sorry to ramble on, just hope someone has a thought on this.

I know this is an old thread but LAZARETH COME FORTH!! LOL Anyways. I'm dealing with this issue as well. To describe the sludge, it's like algae slick in your hand but brown like mud. Like him it was only in my coolant reservoir. Radiator was completely clean. I took it to a mechanic who is very reputable he said "Blown Head Gasket" previous owner was a Chevy Mechanic. I was hoping he didn't pull a fast one on me. So i did all the tests, checked oil (Fine), Flushed Coolant and lo and behold it's Dex-Cool Orange...i was like well.. Shit. Flushed all that crap out and put some universal in hoping it won't do it again. I flushed the radiator out a few times and took the reservoir out it was super easy 2 bolts and the hose. Flushed it out with water but couldn't get the death cool sludge out. So i put white vinegar in there shook it up really good and a good majority of it came out no problem. So it still had me worried about blown head gasket i checked plugs, compressions, and even bought the Combustion tester kit and it stayed blue. The car runs great and doesn't ever get hot which was strange so i think i just had bad coolant. I'm bout to change out the water pump because it's making a strange noise. Could i drain the block of all that crap when I do that? I have the loudmouth as well and mine back fires a little when i gas it and am flying through the gears so i think that's normal.

[Nailheadguy455]

Dexcool is a demon when it comes to mix-metal heads. It does little to nothing when it comes to Steel block/steel head. Any other Mixture between block/heads/radiator and your're looking for trouble. Best bet is, "Water Wetter" or the Prestone universal. If you are mixing your own (not using 50/50 out of the bottle) try to use distilled water. Ive followed these guidelines through a ton of GM engine builds and I haven't had a problem.