Is DexCool bad?


lewisp
04-30-2008, 08:31 PM
Hi all,
Haven't been to the Buick boards before, but AF gave very helpful advice on my last car, so I'm back!
I have a 2000 Century, 3.1, 70K miles, owned it for about a year. Today at an oil change, the mechanic pointed out a bunch of gunk under the coolant system cap. He recommended flushing out the DexCool that I have in there and replacing it with the plain old green stuff. He said he sees lots of 3.1s especially that have the plastic parts kind of chewed up by the Dexcool, for example the intake gasket, which sounds awfully expensive! (I think I do have some leak in the coolant system already, because I've had to add DexCool a couple times in the last two months since I noticed it getting low. Hopefully there's not terrible damage already?! :shakehead) I've been reading that the brown gunk happens usually when you mix the green and the red stuff, and I don't know what the previous owner/dealer put in there, though I assume the recommended DexCool. Now I've also called around and heard from another mechanic that DexCool is fine. Any experience here?
So I assume I need a coolant flush to get the gunk out, and I have a few questions:
1. is it likely they'll get all the gunk out in one flush, if it's pretty dirty? (don't really know how dirty it is, just saw the cap)
2. though the book recommends the DexCool, will it damage my car to run the regular green stuff? Or do I just need to change it more often.
3. relating to #2, I know it's bad to mix even a little of the red and green stuff -- is there any way to make certain that there are no traces of the red stuff left in the system, before they put the green stuff in?
Sorry so long! Thanks for any help!

'97ventureowner
04-30-2008, 11:13 PM
Hi all,
Haven't been to the Buick boards before, but AF gave very helpful advice on my last car, so I'm back!
I have a 2000 Century, 3.1, 70K miles, owned it for about a year. Today at an oil change, the mechanic pointed out a bunch of gunk under the coolant system cap. He recommended flushing out the DexCool that I have in there and replacing it with the plain old green stuff. He said he sees lots of 3.1s especially that have the plastic parts kind of chewed up by the Dexcool, for example the intake gasket, which sounds awfully expensive! (I think I do have some leak in the coolant system already, because I've had to add DexCool a couple times in the last two months since I noticed it getting low. Hopefully there's not terrible damage already?! :shakehead) I've been reading that the brown gunk happens usually when you mix the green and the red stuff, and I don't know what the previous owner/dealer put in there, though I assume the recommended DexCool. Now I've also called around and heard from another mechanic that DexCool is fine. Any experience here?
So I assume I need a coolant flush to get the gunk out, and I have a few questions:
1. is it likely they'll get all the gunk out in one flush, if it's pretty dirty? (don't really know how dirty it is, just saw the cap)
2. though the book recommends the DexCool, will it damage my car to run the regular green stuff? Or do I just need to change it more often.
3. relating to #2, I know it's bad to mix even a little of the red and green stuff -- is there any way to make certain that there are no traces of the red stuff left in the system, before they put the green stuff in?
Sorry so long! Thanks for any help!
The general answer for your main question is no, Dex Cool is not bad for your car.
First let me answer the questions you asked in your post.
1) There is a chance you might not get all of the gunk and debris out of the cooling system with one flush. A lot depends on the technician's experience and what process they use. The more experience and better equipment can get most of the junk out of your cooling system out on the first attempt. With that in mind it might be a good idea to take the vehicle to a radiator shop or an independent shop that specializes in radiator services/cooling system flushing.
2) There is a very good probability that you could damage your system by running the green coolant. Here is a link to an article saying why you should continue running Dex Cool in your system if your car came with it from the factory:http://free-auto-repair-advice.blogspot.com/search/label/Dex-Cool .
Putting it in simple terms comparing Dex Cool to the old standby ethylene glycol coolant is like comparing apples to oranges. Dex Cool is formulated for modern engines while the green stuff is good for your grandfathers old Chevy.Dex Cool is an OAT (Organic Acid Technology based coolant and is specifically made for your modern engine.
#3 Is really a moot point if you stick with what you are supposed to use as recommended by the vehicle manufacturer. You can't always be sure if you get all the Dex Cool out of your system.

The problems related to Dex Cool can be traced to poor gasket materials and design and air getting into the cooling system and causing sludge. Newer style gaskets have been introduced lately to correct the first problem, and the second one can be rectified by making sure all the air is bled out of your system, and by checking your radiator cap to make sure it is working correctly.
Proper maintenance is the best way to ensure a well operating cooling system. Checking the condition of the coolant and changing it out on a regular schedule, (some follow a 2 to 3 year or 30,000 to 40,000 mile time period,) making sure your radiator cap is functioning properly and keeping the level in your overflow tank where it should be are some of the ways to accomplish this. And do not mix Dex Cool with other coolants as it diminishes the effectiveness and protection package Dex Cool affords your engine and can cause issues in the future.

RTjman
05-07-2008, 11:05 AM
Lewisp,

Hey I figured Id give my 2 pennies on your post. Well, my '01 Buick Centruy Custom had the exact same dexcool sludge/intakegasket problem, as alot of these do. I waited (procrastinated) for quite some time while reading posts, talking to different people, hoping my engine block wouldnt explode... Basically, I knew it'd be around 5-6 hundred bucks and I thought it was bull that GM would have such a wierd issue like this and not do anything (recall) about it- even IF it is an older model. But yeah, long story short: I managed to get it done at a small shop for 425 bucks, and aside from a hose coming from the intake gasket getting a little loose one time, i havent had a problem with it since! (knock on wood). I like the green coolant better, as it is more readily available and alot less expensive, in the case that more is needed. I dunno wether I helped or not... But I HAVE been there, and thats what i did :)
-Ray

northwichita
08-28-2008, 08:54 PM
Type in dexcool in a search and see for yourself the responses. Lawsuits, consumer complaints, etc etc.

I've bought vehicles with brownish sludge disguised as radiator fluid. Multiple flushes later, I still see traces. I won't buy it / use it if I can help it. I'm sure it works if it's replaced, but people don't bother, and it turns really bad.

Chevy59Diesel
08-28-2008, 10:03 PM
My 99 Yukon had it in the system when I bought it. It had 69K on it and the intake gasket was bad as well as the waterpump. Chevy garage did the repairs under an aftermarket type warranty. Before the repairs were done I changed out the red for green, what I found out is that the red and the green DO NOT mix, the red (dex-cool) is lighter and floats to the top in the radiator. When under pressure it goes to the overflow bottle first draining it off and replacing it with green was easy, and yes it all came out. By the way the Chevy garage blamed my change for the bad gasket and water pump...BULL. I have since put another 60k on it with no trouble at all.

BNaylor
08-28-2008, 10:23 PM
:rolleyes:

Dex-cool works fine as long as it is replaced NLT 5 years or 150K miles, whichever comes first. But the same is applicable to any anti-freeze. Sooner or later it should be replaced as part of preventive maintenance. Also, the aftermarket extended life coolants should not be mixed with Dex-cool regardless of what those companies that make it claim. The issue with '97 and up Buick Century models with the GM 60 degree 3100 V6 engine was the lower intake manifold (LIM) gaskets and IMO not the Dex-cool. The sludge many experience is a result of combustion by-products and oil getting into the cooling system due to the flaky LIM gaskets.

I still use Dex-cool in my '01 Regal GS with no issues. Also, in our '02 Olds Alero with the 3400 V6 which had the LIM gaskets replaced. The Dex-cool was drained, cooling system flushed and new Dex-cool installed well before 5 years since that came before the 150K miles. There are millions of GM cars on the road today that still run Dex-cool so go figure.

richtazz
08-29-2008, 02:36 PM
I agree with Bnaylor that the intake issue is unrelated to Dex-cool. The only knock I have against Dex-cool is that it doesn't truly last the advertised 5yrs/150k miles without developing sludge. Sludge is formed by contaminants such as combustion by-products and air intrusion into the cooling system, and flushing and replacing the coolant is the only solution to sludge. The intake issues on the 3.1/3.4's are caused by a junk plastic framed intake gasket, combined with a bi-metal engine and very low intake bolt torque values. I've done many intake jobs on these cars and used the improved-design metal-framed intake gaskets and fresh Dex-cool and haven't had a leak issue or a sludge problem yet. If you want to save money and switch to the Prestone Extended life coolant instead of Dex-cool, I've used it as well with no adverse issues.

BNaylor
08-29-2008, 03:16 PM
I'd like to point Rich that you can and will get the sludge if the LIM gaskets are bad on either the 3100/3400 and SII 3800 with even Prestone Extended Life Coolant so I would not let my guard down. Switched to Prestone EL on the wife's '99 Regal LS well over a year ago. Canned the Dex-cool but with a very thorough cooling system flush. When the LIM gaskets finally went bad around 132K miles I noticed there was the sludge especially in the coolant reservoir and forming on the radiator filler neck and cap. So the sludge is not limited to Dex-cool only. However, never got the sludge with the Dex-cool.

Blue Bowtie
09-13-2008, 09:55 AM
Is Dex-Cool bad? Well, I wouldn't drink it.

For use as a coolant, however, not only is there nothing wrong with it, but almost EVERY vehicle manufacturer is using the same OAT coolant for their original factory fill, including Chrysler, Honda, Toyota, Nissan, and even the Europans are catching on. That includes Cummins and Caterpillar in some of their large engines. The product isn't the problem. Ignorance of maintenance and monitoring is the problem. Monitor pH, DS, and TSS, Make sure the system is full and completely purge of entrapped air, and change the coolant when necessary. Most of all, DON'T mix it with anything but clean water or more DexCool.

BNaylor
09-13-2008, 09:16 PM
Good advice. However, I would stipulate distilled water but to each his own. GM's claim it is OK to use tap water to mix/dilute Dex-cool doesn't make sense.

Satellite
09-18-2009, 10:05 PM
much to my surprise I found out it was red and realized later the rad cools the tranny as well, geuss that is the formula, auto parts told me that there rad is allso different from green, to all the other posts on sludge man I have seen some rotten green gunk from down in the swamps of many a Rad:grinyes:

3800Bird
09-13-2010, 03:56 PM
I have owned 2 different 1999 pontiac firebirds which have the 3800 engine one of which formed the sludge under the radiator cap. After some more investigating i found the the one with the sludge had bad intake gaskets,they looked like they had melted and the other car had the newer style gaskets. so i do believe it could be faulty gaskets. other than that one case ive never had trouble with DexCool. on a different note i work for the city fleet dept here and we use DexCool in all our heavy fleet including a fleet of over 100 automated garbage trucks, which in the summer are constantly stopping and going in over 100 degree temps.

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