By on May 28, 2009

TTAC commentator jpcavanaugh writes:

My mother is in her mid 70s. Of course, she drives a 2006 Buick LaCrosse with about 10k miles. It is the first GM car in our family since the 1970s. She planned to remain a loyal Ford customer for life after 20 happy years with a pair of Crown Vics, but she won the Buick in GM’s last Hot Button contest.

I recently learned of this stuff called DexCool that is the factory-fill radiator coolant. From what I have read, I do not much care for this stuff. If it were my car, I would drive quickly to my independent mechanic and flush the system with the old-fashioned green stuff. So what do I tell mom to do? The choices, as I see them, are (in order from my least to most favorite ideas):

1.  The car only has 10K miles, coolant is probably fine, leave it alone.

2.  Even though the car only has 10K miles, try to get the Buick Dealer to flush it and refill it with the green stuff, which they probably don’t stock and which they will probably refuse to do.

3.  Even though the car only has 10K miles, have the Buick dealer flush and fill with fresh DexCool, and to do this every 2 or 3 years, even though the mileage intervals will be really low.

4. Her Ford dealer offered to service the Buick to keep her as a customer, and she might be willing to do this, as she had always been quite happy there. Take the car to the Ford dealer now, get it flushed and refilled with green stuff then make sure the Buick dealer never ever touches the cooling system.

5.  Leave it alone till the warranty is up in October, take it to the Ford dealer, have it flushed and refilled with whatever they use and have the car serviced there from then on.

Sajeev replies:

No matter where I look, there are far too many valid concerns about Dex-Cool. So, yes, flush it out and never look back.

But I think time and low mileage are on your side, so wait for the warranty to expire and go to town on that cooling system. Make sure the Ford dealer knows the repercussions of not flushing out all the old stuff: aside from goo-ing up the cooling system, Mom can lose her heater when D-Cool mixes with green stuff and slimes the heater core, Ghostbusters style.

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24 Comments on “Piston Slap: Pushing the Hot Button to Slime GM’s Dex-Cool?...”

  • avatar

    If you choose the flushing route, be sure the wash the hell out of that cooling system.

    If some Dex-Cool remains, you will be fubard.

  • avatar

    This topic is debated as commonly as oil preferences.

    The biggest problem with Dex cool is that it will tend to gunk up if the cooling system is compromised – adding contaminated water or old-style green coolant are the two most common ways to break it.

    Further, the aluminum systems that use it, have both the coolant color and the lack of red rust working against them to give any indicator of when the coolant is failing.

    There were problems in the early years of the changeover but in general I would not recommend a swap in a 2006 (2000+ or so) vehicle.

    You should still flush the system per recommendations. A lot of the problems occurred because people didn’t have the visual indicator (green turning brown) they had with the old stuff and therefore didn’t do a flush when it was needed.

    If despite all of this, you decide to go forward with a changeover, you’d better use a universal coolant or make sure the entire system is purged of all Dex Cool. This means an active flush (multiple times, maybe) and removal of block drain plugs, etc. As sting mentioned any mixing of the two and you’ll be a lot worse off than before.

    My standing recommendation is to do regular flushes as recommended with Dex Cool. Do it on a more frequent green coolant schedule if you are paranoid.

  • avatar

    The original DexCool was indeed bad shit if used incorrectly. It had an organic additive that became worthless when it came in contact with chlorine. The DexCool made since 2006 is different, and can be safely used with chlorinated water without the mud. Many people think it’s all the same, but the old stuff is no longer available. If your car came with the old (pre 2006) DexCool do not change it over to the green stuff, just use the new DexCool and it will be fine.

    In short, your mom’s car should have the new stuff in it, I’d leave it alone. If you’re concerned, just have a flush done with the new stuff and you’ll have no issues.

  • avatar

    As if we all needed another reason to run away like your ass is on fire, from even the thought of buying a Gov’t Motorz junkpike piece of absolute drek.

    I had Dexcool in a 1997 Cavalier, and thank God that I broomed the car after only 2 years.

    Constant brake rotor warping (and an absolute refusal by the local Chevy dealer to correctly fit new rotors, instead of continually “turning” them and making the cheap components even worse).

    Then there were the driver’s side windshield wiper which would clamp onto the car door and stay there while the right side one worked.

    Then there were the mysterious periodic electronic transmission glitches.

    Never more, for me.

  • avatar

    I have been using DexCool in many of my family’s cars for about 12 years. Subarus, Chevys, Fords. I have never had any hint of trouble. My parents’ Impreza has over 140k miles and has had nothing but DexCool for the past 12 years, knock on wood. This coolant was developed by Total (yes, not ChevronTexaco) and I trust them.

    I think a lot of problems with DexCool have to do with a) poor cooling system design, b) long change intervals, c) using tap water. I change it every 3 years and use only distilled water.

    Stop bothering your mother, Sajeev :) Just tell her to pay for a coolant change at her Buick dealer every 3-4 years and everything will be fine.

  • avatar

    I had a problem with DexCool on 3.1L engine in a ’01 Buick Century. I paid about $800 to replace intake manifold gaskets and flush the cooling system. I’ve got $400 back from the DexCool settlement.

    I don’t believe there were many DexCool problems with 3.8L engines or any newer ones, like 3.6L in LaCrosse. If I’d be you, I wouldn’t mess with the current coolant for another year or two, but I would keep an eye on it’s condition – clouding, change of color, etc.

  • avatar
    Eric Bryant

    Some “fun” reading on Dexcool:

    Links to Part 2 and 3 are at the bottom of the first page. No endorsement is expressed or implied, and I have no association with the responsible entity; I just thought that it’s one of the better articles on the topic.

    As for me, I lost an engine due to Dexcool. The intake gaskets on the Vortec 350 in my ’96 GMC failed and dumped most of the coolant into the oil sump during a hot start. After the rebuild, I now use the yellow Prestone “mixes with everything” stuff.

    Anyways, back to the question at hand – I’d personally leave it alone for right now, and change out the coolant at the five-year mark (which, considering that this MY2006 vehicle could have been built in 2005, is probably not far away). Changing it out sooner would not be a bad idea, considering that the vehicle’s low mileage likely indicates that the car frequently sits unused or sees a lot of short trips. Back when Dexcool was introduced, either scenario would have called for a shorter change interval than the claimed 5yr/50K. I don’t know what is now indicated for vehicles with this usage profile.

  • avatar

    My nightmares with Dex-Cool go back to 1996 and is worthy of an editorial in itself but, I won’t bore you with it here.

    That being said, immediately after taking delivery on my 2008 Corvette, I drove straight to the auto center and had the Dex-Cool power flushed out.

    Getting rid of Big Brother OnStar was a little bit harder…

  • avatar

    For a car that is being driven 3,300 miles a year, I can’t see the value of getting rid of the Dexcool. For what it’s going to cost you to do a flush that works, you can replace the Dexcool every year for several years.

    Just sitting in the engine the Dexcool isn’t doing any harm. If she’s driving 3.3K miles a year the odds of needing to add any water (chlorinated or otherwise) are about zero. Any problems that are going to show up aren’t going to show up for a long time, if ever. (See the poster that says Dexcool has been fixed).

    If she drives it 3.3K each year average for the next 5 years you’re only going to have 27K miles but the car will be 8 years old by then and essentially valueless anyhow.

    So, I think that the odds of not actually getting all the Dexcool out of the system and having it go wrong are higher than that of having the Dexcool give you a problem over the next 5 years, and having an annual replacement of the Dexcool when you do your annual oil change (you do change the oil at least once a year, don’t you?) should keep the problem away for as long as it’s going to matter.

    Finally, I have learned too many bitter lessons with my own aging mom about attempting to do something to help her (on the same order of flushing Dexcool and replacing it with green stuff – think changing insurance carriers, cell phone companies, et al) and having it all become too much hassle. Of course, I get it taken care of in the end, but to my mom, it’s just proof than I’m really still just 11 years old.


  • avatar
    John Horner

    Getting rid of Dexcool is an ok idea, but the “green stuff” is almost impossible to get now. Since Grandma has a good relationship with the Ford dealer, she could go there and have them replace it with the coolant used in new Fords (G-05) these days, which is a different advanced technology long-life coolant than Dexcool. It isn’t easy to find a shop/dealer you like and trust … so going to her long time Ford dealer for service makes all the sense in the world to me.

    With the 2006 changes to Dexcool she is probably not going to have a problem, but if it makes you feel better, go with the modern Ford stuff. Option 5 makes the most sense to me.

  • avatar

    Notice that most Dexcool horror stories usually involve 90’s models and some early 2000’s. The Dexcool in your 2006 is fine. I have it in my Impala with 47K with not a hint of trouble. My parent 2001 Bonneville with 99K has suffered no issues. My buddies 2006 Impala LTZ with 50K has had no issues. Exercise common sense and you will be fine. Break open the owners manual if you have one with the car and see what it says. A good rule of thumb with any of today’s antifreeze is to chop the recommended change interval in half from what the manufacturer says for normal driving conditions which seldom exists today. I always follow the severe intervals when it comes to coolant and transmission fluid. Your Buick with only 10K miles should be fine for now. If your car has the 3800 it will be the newer series III version which uses a composite steel upper and lower intake manifold. These engines have so far proven to be very bullet proof and far better than the series II motors before them.

  • avatar

    I have ranted about dexcool on ttac before. The last time, I went into detail about my experience with it but here a quick rundown of what I know:

    Dexcool is considered an OAT coolant. OAT stands for Organic Acid Technology. It was designed for aluminum engines (presumably because of the problems with the Cadillac HT4100 engines in the eighties, but that is just my speculation) Problem is, when they allowed it, they put it into every GM product all at once. It seems to attack their older iron block pushrod engines that previously had the older, green (alkaline) coolant.

    Ford was the only other automaker that tried Dexcool. It was in the 1999 Mercury Cougar and it was a disaster. They switched back to the green stuff in 2000 and to this day they have a “No Dexcool” sticker on the coolant bottles of every vehicle they sell.

    European cars have used a non Dexcool, Hybrid OAT since atleast the 1990’s Ford and Chrysler since about 2003 (theirs is yellow) and Toyota’s Hybrid OAT coolant is red and is commonly called “Toyota Red” They are all very similar, but different from Dexcool.

    Bottom line, look at pictures of what happens to the GM 3800 engine with Dexcool and make a decision. After loosing an engine to Dexcool, I decided to go with a Hybrid OAT coolant like EVERY OTHER AUTOMAKER EXCEPT GM. It works fine and did not further coat the cooling system with crud.

    Dexcool is a brainchild of the company who brought you the Corvair, the Vega, the “Dieselized” gasoline engine, the Buick 231 V6, the V8-6-4, the HT4100, the Cimmaron, The Northstar Engine, a “throwaway motor” that will leak an alarming amount of oil and dissolve its head gaskets before 150K miles.

    The company is a loser. For every good thing they make, there are 3 things that they do that range from questionable to horrific.

    Bottom line: Drain the Dexcool before it goes south (before 40,000 miles) and refill with the yellow Ford coolant. Or even toyota red. (or any other coolant that a car company that could be considered a “going concern” uses.) No green stuff, save that for your classic cars. Then that car should last 8-10 years or so, maybe.

  • avatar

    I had a ’99 Intrigue that ran this stuff (3.5 Shortstar V6). Really, never had any problems with it other than the occasional topping off. I had it flushed at around 100K miles, replaced with more Dex Cool, and ran it to 135K until I sold it. I did make sure to tell the kid who bought the car from me never to mix the two types of coolant, and gave him my 1/2 empty bottle of Dex.

    As for the writer, it’s his mom’s car, she barely drives it, and the car is new. I don’t see a need to do anything about the coolant for a while.

  • avatar

    My mother is in her mid 70s. Of course, she drives a 2006 Buick LaCrosse with about 10k miles.


  • avatar

    Too many problems with Dex-Cool. I understand your concerns.

    But that doesn’t mean you should go back to the old “green stuff”. Advances have been made.

    If it were my car, I would do a *complete* flush of the existing coolant, and I would replace it with PEAK Global LifeTime mixed with distilled water. Good stuff, will last forever in case she forgets to replace it, and won’t have nasty chemical reactions in case the corner greasemonkey tops off the reservoir with god knows what.

  • avatar

    The only thing missing from the equation is that Dex-Cool’s color should have matched that of Jim Jone’s grape kool-aid.

  • avatar
    George B

    Keep the Dexcool, but change the coolant much more frequently like every 2 years. If not premixed, only use distilled water. Since it’s your mother’s car and you don’t have control over what coolant is added in the future, there is a risk that someone else mixes in some Dex-Cool with an incompatible replacement coolant. The other issue is warantee coverage. Replacing Dex-Cool with something else might void part of the warantee.

  • avatar

    Texaco/Havoline made DexCool. Not GM. The problem has to do with components that didn’t react well with DexCool including gaskets and the radiator caps. Not every vehicle with DexCool had problems.

    Here is a list of vehicles that did.

    No need to change the coolant. It should be fine.

  • avatar

    The issue with Dexcool was the fact that its organic anti-corrosion additives were incompatible with the gasket materials GM was using for a while. GM supposedly “changed” the materials used in some of these gaskets around 2003 or so, but the issues continued after that – my parents’ 2003 Chevy Venture still had the same intake manifold gasket issues that their ’98 Venture did.

    In short, I’d flush out the Dexcool ASAP. It has no genuine advantages over other coolants and it seems to cause all sorts of problems wherever it gets used.

  • avatar

    Thank you all for your suggestions and advice. I am now armed with some knowledge for the next visit with Mom when she asks me what service the car needs to have done. The goal is for this car to last as long as she does, which should be a while. No more than she drives, there will be no reason to replace this car when it is 10 years old and has 25000 miles. She has always taken good care of her wheels, so good maintenance should not be a problem.

    In my sheltered little non-GM world, I had never even heard of Dexcool until about 6 months ago. Npbheights sums up the litany of GM sins quite nicely, and this adds to it. That said, the Lacrosse is the first GM car I have driven built after about 1968 that has a real feel of quality to it. Everything you touch feels good and substantial. The car feels heavier than it is (but GM has always been good at this) and is not a bad car to drive. I just wish I could get the radio to play something besides Lawrence Welk.

  • avatar

    The days of Prestone fits all cars is gone.
    Aluminum engines are much more at risk than Detroit Iron of years gone by. Every mfg has their own spec additives. It isn’t worth the few extra bucks not to use GM recommended coolant when recommended.

  • avatar

    Dexcool is fine in most cars EXCEPT GM products and most Fords. Go figure. I don’t care if they’ve got the latest greatest gaskets in the intakes… FLUSH IT. Add some gasoline, BURN IT.

  • avatar

    I thought that DexCool got the blame for GM’s crappy assembly and crappy gaskets. I use to own an Alero with the 3400 in it that had the lower intake manifold gasket go like every other one.
    A lot of people blamed DexCool for eating away at the gaskets, but apparently as a cost saving measure GM slightly changed the assembly method. Along with a cheaper gasket, they used fewer bolts. In addition to not securing the gasket as tightly they were often over tightened and often not properly aligned… leading to shorter gasket life. Gaskets go, coolant leaks…. very slowly and often in to the engine so there is no tell tale stain on the floor and very little, if any, white smoke. Nobody checks their coolant level and when the idiot light comes on the dash the damage is done…..

    Since most people expect that the gaskets on their engine will start leaking a bit later in life than 42k miles, they blame it on the coolant.

    My first and only experience with GM quality.

  • avatar

    From my personal experiences, the “gunk” was actually pellets that are put into the cooling system at the factory that are designed to seal leaks in the system.

    I’ve had several cars this dexcool and never had a problem with any.

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