dex-cool

I have a 97 chevy venture. I have owned it for 5 yrs. just now reaching 90,000 miles. I am a mechanic I know of the problems concerning dex-cool antifreeze. I have worked on several related problems due to dex-cool in my driveway for friends. Cooling system sludge, intake gaskets, blocked heater cores and valves, head gaskets, sludged oil pans due to obvious head and intake gasket leaks, oil pumps, and so on. Going back to my 97 venture, I have always gave up to date and regular maintenance on my venture. Just the other day it starts acting a little funny, I went out to check the coolant, its sludge, I flush and change the coolant. Dex-cool continue to sludge again I replaced the oil and coolant. My belief on this situation is that the engine seal gasket. plugs allowed a bi-chemical oil, fuel, vapor, and so on to contaminate the cooling system which sludges the engine. I am now in the process of replacing my engine due to a loss of oil pressure. Which I am going to document. I believe once the engine became sludge in the cooling system, it insulated the block from transferring heat properly to the water which in return caused hot spots in the block. Which caused the breakdown in the oil which caused the block in the oil pump. Being it is aluminum block and it transfers heat and cold properties efficiently this is all easily inderstood . Now add to the fact that this cooling system has became completely faulty at doing its job due to the sludge and the dex-cool properties. We recognize the fact that the dex-cool has sludged, the radiator has sludged, heater core, heater velves, and general cooling passages, add to this the resistance that the water pump has taken on due to the sludge, which I believe causes premature failing of the water pump and cooling system. Which obviously explains the end of the means for the engine. I believe that these can be chemically proven easy enough in a lab by breaking down the dex-cool. Then submitting it too the various bi-chemicals created by the engine relating to different metal properties, exhaust gas properties, oil, fuel, and then possibly by someone going down to get a lube, oil, and filter chnge and them topping it off with the wrong anti-freze. Let's get this stuff into a lab, let's shake it up, stir it up, and let's see what the true sastitics of this is, there are too many people and too many things to say this is not happening. Thank you for your time and please contact me and let me know. I wil be pulling the engine out this weekend and having the radiator flushed, would anybody like any of this stuff? i think it is readily availabe any where you go. I would be glad to help if I can, I still owe 3000.00 on the van and it is going to cost me 1200.00 to attempt to resolve the issue and I will not be running dex-cool and I believe if someone runs dex-cool from their car they should not void of their warranty. I believe other anti-freeze out there have alot better track record for there age than dex-cool could even attempt. Thank You

http://www.girardgibbs.com/dexcool.html
Thats where that letter went.
Pass it on ...... Thanks Kc Joplin Mo.

The problem isn't with Dex-Cool directly, it's with people not paying attention to their fluids. Dex-cool starts to gunk up when air is introduced into the system. People with leaky coolant systems or those that don't keep the overflow tank properly filled usually are the ones who end up having a large air pocket at the top of the radiator. So the gunk starts forming, cycling through the system.

The leaking gaskets are not the fault of the problems with Dex-Cool. Dex-cool problems are the result of the leaky gaskets (amung other things). GM has a definite problem with the early 3.1 and 3.4 engines. But blaming it directly on Dex-Cool is just trying to find a scapegoat to blame. In reality, they were just poorly engineered.

dex-cool is total garbage.they claim it will last up to 100,000 miles which is bull.there is some kind of chemicial in that stuff that justs sluges up and makes big time problems.thats the reason head gaskets blow all the time becasue it eats at the material.there is another antifrezze out there that is eqaul to dex-cool but better.i have never seen regular antifreeze sluge up when it gets air in the system.where did u come up with that being for dex-cool.

just all in all dex-cool is junk and i wouldnt ever put that in any of my cars.just my :2cents:

Actually cdru is correct. The big mistake GM made was saying the Dex Cool was good for 5 yrs/150,000 miles. This caused a lot of people to "neglect" their cooling systems since it appeared they didn't have to service it that often. As a result air infiltrated the cooling system causing sludge to build up in the system. Dex Cool should be treated as the old ethylene glycol antifreze, and needs to be drained roughly every 2 years, or 30,000 miles, along with a cooling system flush and replacement of the radiator cap. The cap has been known to fail and let air into the cooling system as well. Using a new cap is insurance against this from happening. Vehicle owners should also keep a vigilant eye on their coolant resivoir tank and not let the level go below the reccomended lines on the tank. Constant refilling of the resivoir tank indicates a problem, which needs to be looked into immediately for the cause.

What I have noticed on my Silhouette is that the hose going into the over flow tank goes through a grommet. The grommet does not make a good seal and the coolant slips by the grommet with the motion of the van. Now, the position of the over flow hose into the tank is such that when you hit your brakes the coolant is sloshed forward and gets by the grommet. I have noticed dried "pink" Dex-cool on the outside of my tank around this grommet. I keep and eye on my reservoir tank and add very little Dex-cool to keep it at the proper level. I should just put a sealer around the grommet and be done with it.

you have to be carful not to mix the green with the red, i have been told by a GM engine designer about 2 years ago that doing so will cause the rubber hose's to rot, but at the same time prestone now has a coolant that can be mixed with any colour coolant, and it's green

Mixing the two won't cause your hoses to rot. It will however introduce sillicates into your antifreeze. The whole point of Dex-cool is to remove (or at least greatly reduce) the silicates which can drop out of the solution and form large deposits, eventually clogging the system.

I have found out that when Dex Cool forms a "sludge" It is hard to flush out of a cooling system.What kind of chemical would you use?Diesel 1962....

Like Cdru said
Dexcool is not the problem it is the way people use it.
If your car came with Dexcool put dexcool back in it.
It is made and designed for the modern engine.
The only problem with it is it does not last as long as the manf. says.
Just like the 100k before tune up.
It should be changed ever 50K or 3 years and you will have no problems with it.
MT :grinno:

what you need to do if you have a dex cool system is #1 regular flushes like what has been mentioned on here already. #2 use some type of flush cleaner stuff to break up the deposits and whatnot in the cooling system. #3 a good power backflush should dispel any crap in the main cooing system. this leaves the heatercore which youre going to have to flush manually. if you dont re-use dex cool make sure the stuff you use is silicate-free. its friendlier to the iron/aluminum part combinations of your engine. the block is iron as opposed to aluminum. your engine is basically a battery, two disimilar metals in the presence of a catlyst. thats what causes pitting and stuff in the cooling system.

Very interesting RahX, and I wonder if that is what is causing the intake manifold gaskets to fail setting up a sort of electrolosis eating into the gaskets.Repeat after me:

DEX-COOL DOESN'T EAT GASKETS

Dex-cool is not the cause of the gasket leak, a poorly designed gasket causes gasket leaks.

It would be very interesting for someone to post good quality pictures (close up) of a failed intake gasket. I''ve looked at many gasket designs over the years as an engineer, and I'd be happy to put my two cents in as to the design of the gasket and the cause of the damage (as much as could be determined via a picture)....Glen

A mechanic friend of mine calls it Death-cool.

He suggested after the 5 years of 150k miles are up and its time to change it, to go with Prestone or something other than Dex-cool.

You need to Service it.
As stated at the first of this post it is not the coolant you use it is the service that you give it.
Green yellow red or orange or dex cool.
If you go with a 3 year or 50K service on the cooling system you will have no problems with any of them.
Mt

From a service standpoint, the Venture is so poorly designed, in my opinion, GM designed it so the owners could not or would not work on it. For instance, whoever heard of having to, "roll an engine," to install new plugs?Have you owned other minivans? Each one has their quirks. My parents owned a Astro a long time ago that required removing some dash compoents and the firewall to get to the rear of the engine. Rolling the engine forward is nothing new. Many other makes using the 3400 require it. I beleive some of the 3800 require it (Grand Prix for instance but down quote me on it).

Cdru proffeses again: "The whole point of Dex-cool is to remove (or at least greatly reduce) the silicates which can drop out of the solution and form large deposits, eventually clogging the system." VERY, very, very rarely does Prestone cause jelly-like clogging, but jelly clogging seems to be a prety common problem with DexCool. Properly maintain it and it won't "jelly up" as you put it. Neglect it and other problems effecting it and it will cause problems.

It would be very interesting for someone to post good quality pictures (close up) of a failed intake gasket. I''ve looked at many gasket designs over the years as an engineer, and I'd be happy to put my two cents in as to the design of the gasket and the cause of the damage (as much as could be determined via a picture)....GlenWhen mine original one failed, it was obvious where it was leaking from. The orange sealing gasket surface was crushed in several places allowing it to leak. Sorry I don't have any pictures of it.

Otherwise, I don't believe anyone can say unequivocally what is or isn't causing the gasket failures. It isn't feasable, but if we ran pure 100% plain water in the system, would the same gasket fail same as a system with DexCool?The difference between the new and old gasket styles is the addition of the metal inserts around the 4 bolt holes, preventing the gasket from being crushed. Once the updated gasket is used, the instances of intake manifold problems drops signifiantly.

And yes, if you had used water (or even your precious Prestone antifreeze) the same problem would have occured, presuming the water didn't boil off on it's own or otherwise evaporated.

Another question comes to mind; Did GM use that gasket material JUST on the 3.4 engine, or did they use the same material on the gaskets for the four cylinders and V8's? However, if it is the same material used in all their engines then there is something unique in the 3.4 causing gasket failure. If it was NOT the same material, then why did GM use a different material in the 3.4 gaskets and why did they chose to fix something that wasn't broke?All GM 3100 and 3400 engines used this gasket from 96 to 2003 before it was redesigned. 4-cylinders are inline, so they are a drastically different style of engine so the same situations don't apply. The 3800 is a 90 degree engine, as compared to the 60-degree engines the 3100 and 3400 engines are, so the situation is different as well, different model of gasket. It also uses a plastic intake (which is prone to cracking/leaking as well). I do beleive however that the 3800 intake gasket has a similar problem but it's not nearly as prevelent. GTP Dad might be able to say more though.

It's not necessarily a gasket sealing material problem in itself, it was how it was designed that allowed the leak. AFAIK, that actual physical plastic and/or rubber materials are the same.

The difference between the new and old gasket styles is the addition of the metal inserts around the 4 bolt holes, preventing the gasket from being crushed. Once the updated gasket is used, the instances of intake manifold problems drops significantly.

As I think I posted elsewhere, the inclusion of load stops (the metal inserts) tells you that the gasket was being overcrushed either by the initial torqueing or by motion caused when the engine heats up/cools off, etc. The "vee" arrangement drives relative motion that can also scrub or overcompress an intake gasket.

Also, the fact that GM modifed the torque sequence, increased the bolt length, and added loctite to the threads means that the root cause of this failure is load loss and/or overcrushing of the joint. I'm not sure if the latest TSB does all of these things, but I seem to recall they did.

Loctite reduces loosening of the capscrew, torque sequence makes you spread the gasket properly, and the longer bolt makes a longer "spring", so you get less bolt pre-load loss during operation. Check out exhaust manifold bolts - they usually are long with spacers to increase bolt stretch and reduce load loss when they heat up/cool down etc.

I've not heard about any postfix (2003+) owners talking about their gasket failing, and I would think they would have enough time on them to start seeing issues. So it would appear the fix is effective, yet Dex-Cool is still in use.

Hard to look at a gasket and say the material is the same, so they might also have changed the polymer. However, a poorly designed joint will fail no matter what coolant you use, and this appears to be a bad joint design.....just some thoughts - I'm not trying to provoke conflict.....Glen

I've not heard about any postfix (2003+) owners talking about their gasket failing, and I would think they would have enough time on them to start seeing issues. So it would appear the fix is effective, yet Dex-Cool is still in use.


I replaced my intake gasket in August 2002 with the updated version, and my van now has more miles on the new gasket, than the one that failed. And I still am using DexCool, just changing it out every 2 years / 30,000 miles along with a thorough flush. No problems so far...(knocks on wood :lol:)

I told you in another thread, everyone is entitled to their own opinion and you are wasting your time doing all that typing, but it serves to support the old adeage; "The human mind is such a wonderful thing, if you try hard enough you can rationalize anything away."No where have I said you were not entitled to express your opinion. I openly welcome yours and anyone elses opinion. I'm not going to argue some areas of the vehicle were poorly designed and probably could have been designed better or more accessable.

All I did in my posts above is try to stop the myths that are often perpetuated here, such as the original topic of this thread, Dex-cool causing the gasket problems. I won't ever correct someone's actual opinion on something. But when you or anyone else spreads misinformation, you can expect to be corrected. If you choose to ignore what I say and beleive what ever you want to, well, I guess that's your perogative. But at least others might be able to make an informed decision on their own.

You yourself presented several questions such as who ever had heard of rolling an engine forward, whether other substances other then Dex-cool would leak the same way, or if it was only the 3400 engine gasket that has the problem. I tried to answer them factually and to the best of my ability. If you meant to ask them as retorical questions, well, ignore my post then.

I am currently of the opinion that the gasket is the problem and not Dex-Cool. Here's why.

I have a 1995 Mazda Protege that I bought new (inline 4 cyl, iron block/alum head). After 2 years (30K miles), I replaced the green coolant with Prestone long life orange coolant. I believe Prestone Orange is very similar to Texaco's Dexcool, and in fact, is compatable with it. This product had just come out on the market, so I guess I was a guinea pig for trying it. I now have 192K miles on the original engine and it still runs perfectly. No coolant leaks, no visible gasket failures, no coolant disappearing, no overheating, no gunk in either the overflow tank or the radiator. I have maintained it according to Prestone's recommendations which were originally 4 yr./100K and then replaced with 5yr./150K miles.

I also have a 2001 Olds Silo that just had the latest version of GM's intake manifold gasket replaced under warranty. The original gasket and the first replacement, done in Oct. 2002, both failed.

On the next Protege oil change, I will be sending a sample to Blackstone Labs for analysis. I am curious to find out if any trace of anti-freeze is in the engine oil via a tiny leak in a gasket. Based on the exterior signs and how well the car is running, a don't believe there is any problem with using long-life coolant in this Mazda Protege. I will post the results in a few months. This is just one example from a "long-term" user of orange coolant.

Joe

'95 Mazda Protege
2001 Olds Silo

It would be very interesting for someone to post good quality pictures (close up) of a failed intake gasket. I''ve looked at many gasket designs over the years as an engineer, and I'd be happy to put my two cents in as to the design of the gasket and the cause of the damage (as much as could be determined via a picture)....Glen

Here are some links a couple of pictures of a failed intake gasket on a 3.1 v-6

http://home.comcast.net/~gslzmedia/illustrated_2180_s.JPG

http://home.comcast.net/~gslzmedia/illustrated_2184_s.JPG

This is from my 95 Monte Carlo 3.1 V6 engine. When I bought the car it had 94,000 miles on it and I had the intake leak around 125,000 miles. I don't even recall what fluid was in it when I did the repair. From everything I've read, GM started installing Dex-Cool in 1996 and later vehicles but the person who owned the vehicle before me was a women who was big on having her car serviced regularly so dex-cool may have been installed at one point. In one picture you see a piece of the gasket inside the water port which is the inner ring portion of the gasket that was made out of a hard plastic type material that had completely broke down and entirely missing. So what do the pictures indicate as far as probable cause?

"I am currently of the opinion that the gasket is the problem and not Dex-Cool. Here's why. etc, etc.)" WRONG. Just one more item on a long list of GM's stupid engineers screw up's. So what's new?

Let me ask you a question: How much sorrier could GM get than looking at a gasket turned to hard goo then cop out and not replace it for free? I'm a senior citizen and saw quite a few diesel and gas engines torn down and never saw a gasket that looked anything like the pictures. Oil deterroriates rubber and causes it to swell and get mushy the same way that gasket looks, so it had to be the DexCool acting on the gasket, or the gasket succumed to the DexCool, a two fold problem and a double GM idiotic screw up.

Think about it. If they put Prestone in a brand new vehicles I bet my eye teeth the gasket would have never failed. Or use a good gasket to start with because AFTER the fact FelPro developed a gasket that would stand up to DexCool. Then to, when they first came out with Dex Cool GM went totally stupid and said leave the DexCool in 5 years or 100,000. Did you read one of my previous posts? Family member had a radiator repair shop for 30 years then my bro-in-law took it over. He said he can't count the number of heater cores that he has cleaned out and how many vehicles ran hot because the DexCool jellified in the cooling system. He kept some of the jelly and showed it to the customer and gave them a chioce of putting it back in or switching to Prestone.

You better believe, early on GM KNEW there was a problem with DexCool and if they had been smart they would have done a recall and taken the DexCool out and put in Prestone. BUT, if the vehicle is still under warranty you MUST use DexCool or void the warranty. Stupid, stupid, stupid GM. Then when it leaks they want you to pay for their stupid double screw up and then GM wonders why people quit buying their product. WHY? Because hard working people like me threw down their hard earned money for a sorry vehicle and told millions of people to F--- Off and it pi--ed us of greatly. That ain't all, I had a Venture Van and one thing after the other went wrong and they have a chronic problem with the windows getting loose like mine did.

GM burned me and every chance I get I bash them and that gasket problem lost them millions of customers and I AM GLAD IT DID and if GM goes down the tubes I'll p--- on their grave and dance at their funeral. I traded that piece of a junk Venture for a Ford Taurus and all I have done is typical maintenance repairs and I kick my butt because Fords served me wll for many, many years and why I went to GM product I will never know.

I'm American and I buy American products, did four in the military and earned my right to bitch but before I'd buy a GM product I'd buy a Honda.

"As I think I posted elsewhere, the inclusion of load stops (the metal inserts) tells you that the gasket was being overcrushed either by the initial torqueing or by motion caused when the engine heats up/cools off, etc."

Say WHAT? Did you look at the pictures? Man please, maybe it was over crushed but that gasket has turned to soft jelly goo because of a reaction to the DexCool. Let's say it was overcrushed, then why did GM's engineers let millions of engines go out the door with a crushed gasket? Why did the DexCool turn to jelly when exposed to air? Even if it was overcrushed, why did the gasket take on such a hideous gooey appearance like no other gasket I have ever seen? Heating up & cooling off only served to compound the problem/reaction from the gasket deterroriating because of DexCool.

OK, bad gasket exposed to sorry DexCool, two GM screw ups. When I finally got rid of that sorry Venture van I said never again will a GM product sit in our driveway, and I wonder how many people said the exact same thing when GM copped out and wouldn't make good on their stupid mistakes that cost me and others a whole big wad of my hard earned money.

This thread is way too old to continue, but for what is worth, I've had in the family 5 GM cars/trucks with dexcool changed at 80 k, never had an intake failure. Inludes 3.1 and 3.4 engines.

GM burned me and every chance I get I bash them and that gasket problem lost them millions of customers and I AM GLAD IT DID and if GM goes down the tubes I'll p--- on their grave and dance at their funeral. I traded that piece of a junk Venture for a Ford Taurus and all I have done is typical maintenance repairs.
So what are you still in the Venture forums if you hate them and GM so much? Looks like your Taurus is giving you problems as well as evidenced by your posting in that forum. Are you going to get rid of that one now too? Remember no one car or car company is perfect. I've owned over 20 cars, trucks and vans so far all American brand, and will continue to do so. My most recent purchase was a 2006 Chevrolet Uplander, the replacement for the Venture, and I am very pleased with it. And yes it has DexCool in the cooling system. I also intend to keep an eye on it and change it every 2 to 3 years as part of my preventative maintenance program.

I've been a tech for 23 years and I believe that the design is the fault.If it was the dex-cool then why not the small block intakes?Head gaskets? or what have you.There are enginerring faults in all.Ford 3.8?That thing was junk,till you did the head gaskets.Then it was fine.Mitsubishi 2.4 dohc.Gotta change the belt and cover evry 60,000 k,cover warps kills the belt.They all have them.For me,it's not the coolant,as stated 8 million times before in this thread it is the lack of maintenance.How many shop owners here or even techs have had a customer say" I'm at 100,000k I need my plugs changed"?.Why,because they are told that they will last 100,000k.

"Looks like your Taurus is giving you problems as well as evidenced by your posting in that forum." Let's see now, new tires not really trouble with the car. They do wear out you know. Rebuild starter is a maintenance thing and some last longer than others. Replace PCV is maintenance, clean MAF, can of fuel injector cleaner in gas tank, new battery and things that go bad with age and time but I don't call them problems per se. Naah . . . Problem is when you have to shell out $700. to get the intake gasket replaced and apparently lots of others who wanted to file a class action lawsuit against GM and said they would never buy another GM product.
Here you go GM, just for you. :thefinger

I've owned a lot of Ford products and never had any big problem with them anything like that Venture that was a pure dog. If GM had done the right thing and stepped up the plate and warrantied the gaskets they would be a hell'ava lot better off because in my opinion the way they dumped on people was about as dumb as any company could get and it came back and bit them in the butt and I am so glad it did.

"Looks like your Taurus is giving you problems as well as evidenced by your posting in that forum." Let's see now, new tires not really trouble with the car. They do wear out you know. Rebuild starter is a maintenance thing and some last longer than others. Replace PCV is maintenance, clean MAF, can of fuel injector cleaner in gas tank, new battery and things that go bad with age and time but I don't call them problems per se. Naah . . . Problem is when you have to shell out $700. to get the intake gasket replaced and apparently lots of others who wanted to file a class action lawsuit against GM and said they would never buy another GM product.
Here you go GM, just for you. :thefinger

I've owned a lot of Ford products and never had any big problem with them anything like that Venture that was a pure dog. If GM had done the right thing and stepped up the plate and warrantied the gaskets they would be a hell'ava lot better off because in my opinion the way they dumped on people was about as dumb as any company could get and it came back and bit them in the butt and I am so glad it did.
What part of the 3.8 lt Ford have you forgtten?Class action suit like crazy,if you squezed the right srvice counter person it came under warranty.Ford never once gave into the head gasket deal.How many 3.8's are out there.Soreass,Windcraps and god only knows,man I could go on for a month.Talk about a one sided opinion.At least have the sense to admit that they all have thier own issues,but to sit and crap on one and the praise the allmighty for another because they have had no issues at all is just plain old tunnel vision.Dude if you think ford is with out costly problems you are just MISINFORMED.

Misinformed? HeHeHeHe . . . Yeah, been on this planet 66 years did my time in the military and have successful business all from being misinformed. Thanks to guys like me who did their military time you are entitled to your opinion and have every right to speak your mind, so be it.

Thank you, but I'll stick with Fords and Hondas and I'd rather have someone crap in my mess kit than drive a GM product. Henceforth I shall not grace you by replying to your mad meanderings, so rave on, rave on . . .

"Schooling produces intelligent people, but you can't fix stupid . . . "

Here's one for Fords and Hondas that have served our family and kids and grand kids so well. :worshippy

Misinformed? HeHeHeHe . . . Yeah, been on this planet 66 years did my time in the military and have successful business all from being misinformed. Thanks to guys like me who did their military time you are entitled to your opinion and have every right to speak your mind, so be it.

Thank you, but I'll stick with Fords and Hondas and I'd rather have someone crap in my mess kit than drive a GM product. Henceforth I shall not grace you by replying to your mad meanderings, so rave on, rave on . . .

"Schooling produces intelligent people, but you can't fix stupid . . . "

Here's one for Fords and Hondas that have served our family and kids and grand kids so well. :worshippy
Somehow we went from a "GM is crap" issue to how great you are for standing up for me and my rights.For that alone sir all I can say is Thank You!Anyman that has gone to war for me and my country deserves at least a Thank You.I am sorry that you had to get mechanical teachings from the military.Not really real world stuff.Works great for other things,tanks & jeeps or what have you.I think you missed the point about being misinformed.It was not a shot about your knowledge,it was about the fact that Ford has dropped the ball as well,and cost alot of peeps some big time dough.Once again,your sour taste for GM has led you into a one sided opinion.As you said,you fought for us so we could have our one sided opinions.

A hush falls on the room.

the vortec 350 in the tahoes burbans ect also leaked death cool.buy a gm flush it out install reg green antifreeze.bottom line dex-cool is crap!!!!!!!!!!!!!
dont see fords leak,toyotas,dodge ect.just chevys since they started using it.....................

the vortec 350 in the tahoes burbans ect also leaked death cool.buy a gm flush it out install reg green antifreeze.bottom line dex-cool is crap!!!!!!!!!!!!!
dont see fords leak,toyotas,dodge ect.just chevys since they started using it.....................
Here is a good website with a better understanding of the coolants out there. http://autorepair.about.com/cs/coolingsystem/l/aa052601c.htm .It is not recommended to flush out and refill with etylene glycol based coolant (green) because it offers a different "protection package" than the DexCool which is an OAT (Organic Acid Technology) based coolant. The OATs are longer term coolants and are dyed a different color to differentiate them from conventional coolants. One problem with switching to "the green stuff" could be a shorter water pump life. (Plus if the vehicle is still under manufacturer's warranty, switching will void it.) Here is a paragraph from that website that sums it up: "So the bottom line is this, if your car came from the factory with Dexcool®, use Dexcool® for replacement or to top off. If your car came from the factory with standard "green" antifreeze, use that for replacement or to toping off. Case in point, Dexcool® has been known to cause head gasket and water pump failure on some Ford OHC V-8's."
As I have stated before, if you treat the DexCool like conventional coolant, and flush and refill with fresh coolant on a regular basis, there is a lesser chance of problems occuring from contaminated coolant.

My lumina ('97) had 2 intake leaks at 2 different times
Under warranty - dealership fixed for free and re-used Dex-Cool

2nd time - out of warranty - had a trusted local mechanic fix it. With out asking - he flushed the entire system, and used normal green antifreeze.

time will tell if there is any difference