DEX-COOL, Conventional Green, & G-05... My Experiences

Looks like a yard ornament now.

BTJustice

"No one, it turns out, likes maintenance less than long-haul diesel truckers. Turcotte told me about Zerex Extended Life. This red juice is designed to go full-strength into truck radiators. Do nothing for the first

300,000 miles or three years. Then throw in another whack of inhibitors, a quart of Zerex Extended Life Extender, and run another 300,000, at which point the engine is probably scheduled for a full tear-down."

Yes and no. It is not complete steam but the beginning of the steam process that opens the radiator cap which is the cause of the pressure. If you open your radiator cap with a completely warm engine you will see what I mean when you see the steam and HOT coolant fly out.

Yes a lot of newer vehicles are losing the radiator cap altogether and simply running it on the overflow tank, but most cars still have a radiator with a radiator cap and an overflow tank that is non-pressurized. I honestly doubt the metal makes any difference, but I have heard the DEX-COOL does not like lead solder which use to be used for the metal lines going into the radiator.

As I said in my original post, my family is a GM family. However, I don't think the GM engineers deserve god-like status or anything. If the coolant is low in your cooling system, the idiot light on the dash should be on to alert the owner of this problem. I personally do most of the work on my vehicle. I might go to a Jiffy Lube in the dead of winter, and, when I do, I bring my own oil and filter. I only make them change the oil and nothing else. Thousand, and arguably millions, of people don't have the benefit of knowing how to do light maintenance on their vehicles and trust the places they go to 100% for that maintenance.

No, but Texeco, the co-creator of DEX-COOL, does. Look here...

Yes I believe changing coolant every 2-3 years is the smart thing to do. However, there really is no hope for DEX-COOL and GM is starting to realize this. Probably within the next few years, especially after this class action lawsuit over DEX-COOL, GM will either go back to conventional green, go to G-05, or come out with something completely different. Hope they don't make blue coolant. I can see someone pouring that into their washer fluid tank already.

According to the Zerex website below, their G-05 meets the current GM specs, but they do not recommend going over to G-05 from DEX-COOL though it is probably safe. Has anyone reading hits thread gone the G-05 from DEX-COOL?

(CLICKON PRODUCT SPECS)

BTJustice

In all fairness to GM, my grampas 97 Silverado (I think that's at ~125k miles and he just changed the Dex-Cool) and my uncles 99 Safari have Dex-Cool and haven't had a problem. Yet our 99 Blazer had the sludge build up (which GM paid to fix and convert to green antifreeze) and we had no heat in the middle of a Wisconsin winter. I can guarantee that the overflow tank was at the full line every time we checked it (hot line when hot and hot line when it was cold). That brings up a question though, how can 2 same engines (the Vortech 4300 in the Safari and Blazer) have 2 very different results with Dex-Cool ?

The quick answer is that water boils at 212 degrees Fahrenheit (100 degrees Celsius). Most engine coolant is running around 175 - 195 degrees Fahrenheit (80 - 90 degrees Celsius) which means that the steaming process has begun. This principle of heating water a little lower than its boiling point has powered steam engines for centuries.

Here is a scenario. You wake up, get ready for work, eat your breakfast, do a few other things, and then go out and start up your car in the morning which has sat for several hours. If it has a temperature gauge, what do you see when you first turn it on? Though most gauges start at 100 degrees Fahrenheit, it is really at whatever the current engine temperature is which is about the temperature of the air it is in contact with whether the car sits outside or in a garage. You are driving along and you will see the temperature gauge go slowly up and up. It will hit perhaps about 200 degrees Fahrenheit and then the thermostat opens letting in the nice cold coolant in your radiator. This will close the thermostat again but it will eventually open again as the coolant in your engine and the coolant that originally started in the radiator balance out in temperature. If you drive a GM vehicle, this is around 175 - 195 degrees Fahrenheit. Water freezes at

0 degrees Celsius and boils at 100 degrees Celsius which is about 212 degrees Fahrenheit. Keep in mind that when water boils it is making a chemical change from a liquid to a gas. As water approaches its boiling point, the steam process starts to where you still have water but it is letting off gas. If you were unlucky in your trip to work and your car overheats, the pressure from the hot coolant in the beginning of the steam process opens your radiator cap and begins to fill your overflow tank. If the radiator cap closes, the coolant in your overflow should be on hot. If it doesn't close due to too much heat, it will overflow.

Water is one of the strangest liquids in the universe as it is the only known one to expand when it freezes and contract when it is heated. Now it definitely gets to 32 degrees Fahrenheit (0 degrees Celsius) almost everywhere in the U.S. so you obviously have to have something in the water of your engine (antifreeze / coolant) to prevent water from freezing, expanding, and cracking your radiator, engine block, etc.

The U.S. should also go to the metric system. 25 degrees Celsius is really nice weather.

BTJustice

"Phillip Schmid" wrote

I can't really answer that question to anybody's satisfaction. I've seen all of the above vehicles with sludging problems in our shop, but the Blazer's are by far the worst. I'm sure that you kept your coolant level up, but most customers don't. And often the coolant level in the rad can be low, while the overflow is full. This is because the rad cap gets so bunged up that it can no longer pull the coolant back into the rad as the coolant cools down.

Ian

Because DEX-COOL sucks and the level was low in your radiator. If you filled your overflow tank to the hot line when the engine was cold and it was at the same level when the engine was hot then the radiator had to be low. DEX-COOL doesn't like playing with air. How is it running with conventional green?

BTJustice

"Buford T. Justice"

That was a typo. It happens. My bad.

BTJustice

My mom has a blazer and it was sludged up. I think there may be a component or type of metal inside the system that causes dexcool to sludge up. Does anyone know if the heater core is aluminum or not? Lets say you have a copper heater core and a aluminum radiator. Thats going to be a problem because the those two different types of metal will act as a mild battery and will cause corrosion in the cooling passages. I highly doubt GM would have made that mistake but some "bean counter" might have changed some fitting or something to lessen the cost somewhere along the way... Anyhow we had it flushed and new dexcool put in a few years back. It looks pretty clean to this day.

Lets keep some things in mind here. The 15 psi rad cap is designed to raise the boiling point of coolant so when you see 200deg it is not steaming or even boiling in your engine. When you start overheating lets say 250 deg then the coolant is boiling. When you open your cap or your hose blows it hits the atmosphear and becomes steam. Its unlikely it was steam before that. If there is air in your system yeah it will expand like crazy and flood out your overflow bottle. If there is no air in your system should see very minor changes in the level of your overflow bottle like I do. As you responded BTJ about the filling to the hot mark. No its not crazy its only a half inch differance and then you still have about 3 inches above that to go. Likely hood of that bottle overflowing with no air in the system is zero if it doesnt go past 220.

Poor dexcool in a glass and let it sit. Let me know when it becomes "muddy".

I've just started a job of pulling off the intake of my dads 98 truck. It was supposed to have dexcool in the system but someone before him had redid the system with conventional coolant which was a horrible mistake. I pulled off the water neck and there is 1/8th inch of crystalized material from the silica in the coolant caked up on the passages in various spots. THIS IS WHY trying to switch to dexcool after the green crap is "impossible". It WILL NOT come out of the system so it will contaminate dexcool no matter how many times you try flushing the system. I took pictures of this crystalized silica coolant crap and I'll put it up sometime soon if you want to see it. I raked at it and it was pretty damn well bonded to the aluminum. A chemical cleaner wont pull that stuff off and out. It would take a media blaster to clean it off.

You are putting out information as if it were fact. As if people never had problems with conventional coolants. You have got to understand that 5 year 150k miles doesnt mean it will last that long. It means it can last "UP TO" 5 years 150miles given its not contaminated or low. You still have to watch and maintain the system like any other system. If dexcool is looking sludgy in a 3-4 year old car does that mean they should switch? NO! Just drain it out and refill it. The likely hood of dexcool clogging the system is FAR LESS than silica based coolants that actually BONDs to metal and block passages. Dexcool sludge brakes up and off into circulation far better than silica crystals and dexcool sludge does not eat away at aluminum like a sand blaster. That is the important factor for dexcool being used, not the long life of it.

"Buford T. Justice"

Carboxylate is organic? That is one of the main ingredients in dexcool.

Gaskets can sometimes be very touchy. They have memories, becoming accustomed to whatever they are in contact most. Don't ask me why, but many mechanic friends have told me this from years of experience. In one instance, they had to redo all the axle seals in a brand new Peterbuilt because they switched to a synrthetic diff oil a month after they got it new. Sometimes just little changes can cause havoc.

Take a carbureted snowmobile fo instance. You would be nuts to not use a gas line antifreeze with it, but use a methyl based alcohol, and you will be looking for trouble. Ethanol or isopropyl everything is good. Even though they are all alcohols, the methanol will eventually eat and crack all your carbeurator seals.

As far as when to change coolant in a semi, they don't go by km's or time, they go by testing it, for ph, and numerous other variants.

Quick physics lesson:

A liquid under pressure under the absence of air will not boil or steam. As you pressurize a liquid, you increase the boiling point. as the boiling point increases, the pressure increases, and so on. This is why the boiling point at sea level is higher than say at 2000' elev. If you have coolant in your rad. at 15 psi. and it is even at 100 cel., it won't be boiling or steaming, because in a properly filled system, there is no air, therefore no room to make steam. Also, it is very important to not have air in your system because of cavitation, not just corrosion. You can't compress a liquid, and since your block is designed to have liquid in the galleries, not having it because of air is greatly weakening your block. Also, aluminum doesn't rust. "Buford T. Justice"

On Sun, 5 Oct 2003 16:53:12 -0500, Buford T. Justice

We had ours flushed and refilled with Dex-Cool last year in October I think and it got all sludgy again within a week.

My dad has a car with the green antifreeze and we had Dex-Cool laying around and he thought that since his looked kind of low he should put in more coolant. My uncle and I told him some of the stories about where people mixed Dex-Cool and regular coolant and he immediatly flushed it and put in the green stuff. Luckily nothing noticeable has happened yet.

We didn't switch, the GM representative told the dealership to forget about Dex-Cool after trying to replace it once and to put regular anti-freeze into the Blazer. We've had 7 or 8 trucks with regular green antifreeze without any noticeable clogging, and 1 Blazer that had Dex-Cool that clogged up, I'm going to stick with personal experiance on the issue between Dex-Cool and regular green anti-freeze.

That's interesting stuff. Thanks.

DEX-COOL is suppose to work with all metals...

(NOTHING ABOUT METAL)

Jesus Christ people! How many times do I have to say it? It is "near the beginning of the steam process". I have never said that the damn coolant and water are steam. DUH! It becomes steam due to the differences of inside and outside temperature.

Of course it won't become muddy. You are forgetting the heat from the engine and the air inside the engine.

Of course it was caked up since the system was not BACK FLUSHED! You have to back flush several times to get it all the DEX-COOL out in conjunction with running a good chemical cleaner that you are suppose to leave in for

4 - 6 hours.

What information have I put out as if it were fact? I know that DEX-COOL will not last 5 / 150,000 but most of the public doesn't know that and assumes that to be true by looking at the owner's manuals of their new GM cars and seeing the DEX-COOL bottles in the stores. The bottom line is that antifreeze / coolant is not suppose to slug! If it does that means it is an inferior product. I think For and Chrysler discovered this and that is the exact reason they stayed with conventional green and have just gone to G-05. I also recommended using Zerex 5/100 Conventional Green coolant as it is a very low silicate formula...

Also keep in mind that the whole point of DEX-COOL was to extend the life of coolant and to cut down on water pump wear. GM was tired of giving away free water pumps but I think their main supplier of coolant was Prestone & Texeco at the time and their conventional green coolants are high in silicates. No matter what coolant you run, replace it every 2 - 3 years.

BTJustice

Good, but I never said it was steam only that it was near the steaming process. Being near the steaming process creates pressure that eventually opens the radiator cap. Aluminum will not rust, but it will corrode. That is why most major coolant companies advertise that their coolant protects all metals from corrosion including aluminum.

BTJustice

Sure is, lol. Glad to hear conventional green worked for you. I hope the people that converted it back flushed it several times and ran a chemical cleaner in it for a 4 - 6 hours to get all the DEX-COOL residue out of that engine.

BTJustice