just curious about dexcool

[2002 gt4me]

I've heard of the dexcool coolant in gm 3.1's eating through the gaskets causing coolant to get into the oil eventually causing serious problems. My friend recently had this happen on a 2000 impala, has anyone heard of this issue with the 3.8's? Just curious if i may have to worry about this down the road.

[GTP Dad]

Dex works for some folks but not others. I guess this can happen with anything. The 3.8 NA engine has had more problems with lower intake manifold gaskets than the 3.8 SC. The older models had more problems than the more recent models as GM did improve the gaskets. If you have Dexcool, you really don't need to change it out, if you decide to do so make sure you totally flush the cooling system at least twice and then use the new Prestone high mileage coolant as a substitute.

Of course anytime coolant gets into the oil it is not good so if you have a gasket issue with the new coolant the same damage can occur or with any coolant for that matter.

[MT-2500]

Dexcool is no worse than any other type of coolant.
With any type of coolant it needs serviced and flushed ever so often.
Dex cool in the real world does not last as long as the manufactures claim.
Forget that 5-7 year 150K deal.
Also dexcool is a little sensitive to air getting in the rad.
Always keep that coolant recovery tank half full.
Forget the 5-7 year 150K deal on dex cool
Use the 3 year 50K flush and clean with it or any other type and you will have no problems.
MT

[pressurerat]

Dex cool is bad news in my opinion. I don't know how many cars I have seen where dexcool has seemed to be the culprit, dozens I suppose. It is very corrosive to aluminum, in my estimation. In engines with aluminum parts that use dexcool, I would say that corrosion occurs at twice the rate of the good old green stuff. I have seen in happen in new cars and classic cars that switched over. I don't know why it happens this way ; I do not fully understand the chemical or metallurgical aspects. I am, however, an ASE certified auto mechanic and have been doing this for about 10 years professionally, and about 10 additional years as a novice. It does seem to cause early gasket failure, I'm really not sure why. I would flush it ALL out (dexcool and green DO NOT mix) and put green antifreeze in it. I did this with my last two GM cars and had no problems. The previous ones, you guessed it, needed manifold gasket replacement. YMMV

[MT-2500]

Originally Posted by pressurerat

Dex cool is bad news in my opinion. I don't know how many cars I have seen where dexcool has seemed to be the culprit, dozens I suppose. It is very corrosive to aluminum, in my estimation. In engines with aluminum parts that use dexcool, I would say that corrosion occurs at twice the rate of the good old green stuff. I have seen in happen in new cars and classic cars that switched over. I don't know why it happens this way ; I do not fully understand the chemical or metallurgical aspects. I am, however, an ASE certified auto mechanic and have been doing this for about 10 years professionally, and about 10 additional years as a novice. It does seem to cause early gasket failure, I'm really not sure why. I would flush it ALL out (dexcool and green DO NOT mix) and put green antifreeze in it. I did this with my last two GM cars and had no problems. The previous ones, you guessed it, needed manifold gasket replacement. YMMV

Well before I can accept the idea that Dexcool is bad for/on gaskets I think we need some documented proof.
Do you have any? If so post it back.
How much ASE certification do you have?
Are You ASE certified on engine rebuilding and coolant systems and gasket replacement?
What does ASE certification say about Dexcool?
MT

[BNaylor]

Too many variables and conspiracy theories out on Dexcool. I've had good luck with it.

Here is Dexcool drained out of the radiator in my GTP when I replaced it with Prestone Extended Life last year. The car is now over 8 years old. The Dexcool was replaced at around 80K miles. It still looks good to me. Probably would have made 100K miles. I saved this for a rainy day.



BTW - The Dexcool was replaced due to preventive maintenance not corrective. No overheating or degradation of the cooling system or manifold gaskets.

[pressurerat]

Originally Posted by MT-2500

Well before I can accept the idea that Dexcool is bad for/on gaskets I think we need some documented proof.
Do you have any? If so post it back.
How much ASE certification do you have?
Are You ASE certified on engine rebuilding and coolant systems and gasket replacement?
What does ASE certification say about Dexcool?
MT

Easy there killer. I clearly stated all of this as my opinion. You don't have to like it, or question my integrity for that matter. Yes, I do have ASE certification on engine rebuilding(gaskets included!), cooling systems, air conditioning, brakes, etc. since you asked. All of my additional dealership training is with Chrysler vehicles and does not matter either, as I no longer work for a dealer. I'm just letting folks know I have some experience in the field of auto repair, and I'm not some yahoo kid working in his back yard . I'm not the best mechanic in the world, and there is always some new issue in vehicles cropping that I have never seen before...I don't know it all. Furthermore, I don't care what kind of antifreeze you use, and I cant 'prove' anything. It's not nice to post on a forum only to have someone cross examine me as if I were on trial. Lighten up. It was just my 2 cents worth.

[richtazz]

The biggest issue with Dex-Cool is the claim it lasts 5yrs, 150k miles, it doesn't. The fact that it is silicate free keeps it from picking up the sludge-making combustion by-products that get in the coolant and keeping it suspended. Dex-cool doesn't prevent the formation of these deposits, and because it's left in so long, it gets dirty and the sludge ends up somewhere in the cooling system. As Dex-cool ages, it gets corrosive, and actually damages the aluminum and plastic components it was originally designed to protect.

[Madmunky]

A friend of mine put that stuff in her Sunfire figuring anti-freeze is anti-freeze (may of mixxed the red and the green) next thing she knew her car was dead on the side of a busy highway at 2 in the morning. When she took it to her mechanic he told her it was because of the coolant...not sure on the details...

Jamie

[BNaylor]

Originally Posted by richtazz

The biggest issue with Dex-Cool is the claim it lasts 5yrs, 150k miles, it doesn't.

I don't know about the 150K mile claim but it definitely lasts well over 5 years.

The Dexcool I drained out of the ole GTP below looks as if it came right out of a new container of Dexcool. No visible contaminants whatsover. However, as you can see even I don't take any chances and replaced it with the Prestone Extended Life.



But it is info worth sharing and shows that not all of us have bad experiences with Dexcool. Just my two cents.

[MT-2500]

Originally Posted by pressurerat

Easy there killer. I clearly stated all of this as my opinion. You don't have to like it, or question my integrity for that matter. Yes, I do have ASE certification on engine rebuilding(gaskets included!), cooling systems, air conditioning, brakes, etc. since you asked. All of my additional dealership training is with Chrysler vehicles and does not matter either, as I no longer work for a dealer. I'm just letting folks know I have some experience in the field of auto repair, and I'm not some yahoo kid working in his back yard . I'm not the best mechanic in the world, and there is always some new issue in vehicles cropping that I have never seen before...I don't know it all. Furthermore, I don't care what kind of antifreeze you use, and I cant 'prove' anything. It's not nice to post on a forum only to have someone cross examine me as if I were on trial. Lighten up. It was just my 2 cents worth.

Well I am sorry if I hit a sore spot. I plum forgot about how touchy an ASE certified Tech might be.
But how was I to know how certified you was until I ask.
But you made the statement.

Dex cool is bad news in my opinion. I don't know how many cars I have seen where dexcool has seemed to be the culprit, dozens I suppose. It is very corrosive to aluminum, in my estimation. In engines with aluminum parts that use dexcool, I would say that corrosion occurs at twice the rate of the good old green stuff.

I understand it was stated as just your opinion but.
Perhaps you could explain this in a little more detail. Or tell us how you have determined or found corrosion from dexcool occurs twice as fast as with green stuff. Or why it you have determined or found out it causes early gasket failure?
I assume you are taking about a coolant system with dexcool that has been properly serviced.
And with all due respects to a certified tech but just a curious mind here so take no offence please but the more info the better all of us can understand things.
MT

[pressurerat]

Originally Posted by MT-2500

Blah blah blah prove it blah blah blah MT

OK. Next time I'll bring photographs, a 40 mule team, and the best defense attorney $100 will buy!

[MT-2500]

Originally Posted by pressurerat

OK. Next time I'll bring photographs, a 40 mule team, and the best defense attorney $100 will buy!

Pressurerat you last answer does not even deserve to be answered.
But here goes.
ASE gasket certified???
You fell hook line and sinker for that one.
Well pressurerat if you cannot give a dissent intelligent answer to a simple question it sure makes us wonder about things.
MT

[richtazz]

I didn't realize antifreeze was such an emotional subject. You guys need to relax. Unless the green stuff says Dex-cool compatible, don't mix them. They will turn to gel and do what happend to Madmunky's friend. I still won't mix them. Either flush it all out clear and start over, or top off with what you have. Just my

[MT-2500]

Originally Posted by richtazz

I didn't realize antifreeze was such an emotional subject. You guys need to relax. Unless the green stuff says Dex-cool compatible, don't mix them. They will turn to gel and do what happend to Madmunky's friend. I still won't mix them. Either flush it all out clear and start over, or top off with what you have. Just my

10-4 on that richtazz
All is cool here. I was just trying to get a answer to a question answered.
Here is a little more info on mixing the stuff I have picked up along the way.
MT

Mixing orange and green leads to brown coolant. Mix orange juice and lime juice and get brown juice. Mix orange KoolAid and green KoolAid and get brown KoolAid. Hey, orange and green will make brown, or some yucky shade like that. Now, as for what it will do to your cooling system, it won't do anything except take the protection level of the orange down to regular green. It has been disputed time and time again about the real useable life of orange anyway, but the orange is supposed to be used for more than just its life expectancy. DexCool has different lubricating qualities and corrosion inhibitors that are SUPPOSED to be more compatible with the vehicle it came in. Green has been rumored to attack those same solder joints and gaskets and provide less lubrication to the water pump.
If your system is supposed to have DexCool, then put DexCool in it. If it is supposed to have green, put green in it. (Please note also that unless the bottle is specifically marked that it contains 50% water, you will need to dilute the gallon you buy.) There are numerous other colors out there too, depending on the manufacturer's requirement. If you are just topping off, you can get the universal long-life coolants, which are usually yellowish. On the other hand, if you are topping off, that means you have a leak somewhere, and you should find out where that is before it possibly costs you a very expensive engine repair bill. If you don't see it leaking outside or smell it outside the car, then it is usually leaking inside the engine. Please note that I said USUALLY - there is only one way to know for sure, and that is to find out where it is going with the cooling system under pressure. If you cannot do this yourself, then pay a professional to do it. Engine bearings really hate antifreeze/coolant, and it usually doesn't take too long to do damage.
DexCool systems are notorious for turning to a muddy pudding, and if let go too long, will turn into what looks like rusty metal shavings, and then the last stage is a reddish-brown clay. If you catch the mud early, you can usually save yourself a lot of headaches. If you get to the other stages, then you may have extensive repair bills to get that all extracted, plus you will probably need a new radiator, heater core, thermostat, and water pump. It ain't pretty. If the system does get to the later stages, you will usually find that the coolant level has not been checked and there is a lot of coolant missing. When coolant is missing, there is AIR in the system. Air in the cooling system creates steam pockets, which have a tendency to create odd temperature guage readings and odd temperatures reported to your PCM or VCM (i.e., computer). It is MY PERSONAL BELIEF that it is these same steam or hot air pockets that do the catalyzing of the DexCool and make it change its state to mud or worse. Every system I've ever seen that had a problem like this is either low when I check it or has been having coolant added to it over some period of time. Also, every one of these vehicles had a radiator cap that would not do its job properly, which may have been the root cause of the problem in the first place. What I mean by that is that the radiator cap would allow the engine to suck air into the system rather than suck the coolant/water mixture out of the reservoir as the system cooled and contracted. That creates an air pocket, for sure. Please also note that this is not the only source of air intrusion, but seems to be the easiest to remedy if caught early.
Do yourself and your vehicle a big favor and check it out thoroughly before it gets too far. If you add coolant to the reservoir on the fender or strut tower and it keeps going down, then you have a big problem. If you have DexCool in the engine and add green to the reservoir, and then the green never changes color or level, then you have a much more serious problem in that the reservoir hose and/or the radiator cap is/are bad. If you have a real radiator cap, then when the car is cold, remove that cap and see if you need more in the radiator in addition to the reservoir.
You want any more specific info, then include your specific vehicle. Hope that all helps some.