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

My family is a GM family. There have been a few exceptions to this. My Grandma's parents owned a Ford Model T, found out it was a piece of junk, and traded it for a Chevrolet. I owned a 1995 Ford Mustang GT for a few months back in 1997 (great car). And my brother currently owns a Mitsubishi Eclipse.

I am the one that usually changes the coolant in my family's vehicles. I remember back around 1996 or so, I was driving a 1985 Chevrolet Monte Carlo and decided to convert it to the new red DEX-COOL coolant that had just came out. When I say "convert" I mean doing my 22 steps below as to obtain a 60% antifreeze to 40% water mixture. I later bought a 1991 Chevrolet Lumina and then a 1992 Chevrolet S-10 after owning several other cars between those and the 1985 Chevrolet Monte Carlo. I converted the Lumina to DEX-COOL. It ruined a gasket that had to be replaced. The S-10 was even worse. After converting it, it would blow smoke out of the tailpipe every time it was started due to coolant leaking into one of the cylinders.

I decided to get rid of the S-10 earlier this month and bought a 1995 Pontiac Grand Prix GTP with every option imaginable. After a few days of owning it, I checked the coolant to find that it was BROWN! That means it hadn't been serviced for quite some time. I figured it was DEX-COOL so I flushed the cooling system and poured in some fresh DEX-COOL. After doing that, I found out it had conventional green instead so, after about 3 days of DEX-COOL, I converted my car back over to green using Zerex 5/100 Coolant. I think I got the DEX-COOL out in time before it could start eating away at gaskets and seals and start spawning that reddish brown mud in my cooling system.

Now around 2000, I converted my Mom's 1995 Chevrolet Monte Carlo from green to DEX-COOL. After finding out about my Pontiac originally having green, I decided to convert her car back to green. I was SHOCKED to find that the DEX-COOL had turned into that damned reddish brown mud. The throat of her radiator and the radiator cap were almost ruined. It took me an good hour of scrubbing the radiator cap with a tooth brush to get it clean.

I did the exact same thing to her car that I had done to mine. I used the back flush tee I had installed in 2000, back flushed her car with the engine running with the heater on high for 30 minutes, poured in a bottle of Zerex Super Cleaner, had her drive the car on and off for about 6 hours, drained the radiator, back flushed again with the engine on and the heater on high for 15 minutes (I was happy to see the mud coming out knowing the Zerex Super Cleaner had done its job), poured in a bottle of Zerex Super Flush and ran the engine for 15 minutes with the heater on high to be sure all the mud was gone, drained the radiator, hooked the hose back up to the back flushing tee, and back flushed again for 30 minutes. I drained the radiator, took out the overflow tank and cleaned it out with hot water, Dawn dish soap, and a bottle brush. I hooked the overflow tank back up, closed the radiator drain plug, put the cap back on the back flushing tee, and poured in Zerex

5/100 Coolant.

That was about a 3 weeks ago. After checking the overflow tank, radiator, and radiator cap, I am happy to report that there is no mud and the car runs great.

All the above is my story with my experiences with DEX-COOL and conventional green coolant / antifreeze. I will now explain what I think of conventional green, DEX-COOL, and G-05.

DEX-COOL

I think this was a bad idea from the start. You would have to be a complete moron to run any coolant / antifreeze for 5 years. A lot of people also have the misunderstanding that they are not to touch it for 5 years. This is just stupidity created by GM.

I think the 2 biggest flaws to DEX-COOL are that if it gets into contact with conventional green directly or through the deposits left by conventional green, it will form that reddish brown mud. If DEX-COOL comes into contact with air either inside the cooling system or outside, it will form either the reddish brown mud or the red "cement". This has been proven by both owners of some 1996 - Present S-10s and owners of other GM vehicles.

I would probably recommend most folks stick with DEX-COOL if that is what their vehicle came with, but a lot of brave people have converted back to conventional green without any problems.

Conventional Green

I think it is the best especially for GM vehicles. If you do an extremely thorough back flush (the 22 steps listed below) you will get all the DEX-COOL out. I would HIGHLY recommend using Zerex 5/100 Coolant which most AutoZone stores carry.

G-05

I have not used this coolant yet, but keep hearing good things about it. It is designed to work in new Fords and Chryslers and has been used for many years by Mercedes and John Deere. I think GM will eventually switch to it.

Now if you would like to back flush the DEX-COOL or any other coolant out of your vehicle, do it this way (you are responsible for what you do to the vehicle you are working on).

1) Buy a few jugs of Zerex 5/100, either a Prestone or Zerex back flushing tee, a bottle of Zerex Super Cleaner, and a bottle of Zerex Super Flush. You might optionally want to go ahead and replace your thermostat.

2) After driving the car for 30 minutes or longer, open the radiator drain c*ck, and let the radiator completely drain out. While you are waiting, find the heater core hose that runs into the engine (not the one going to the water pump) and cut it. Install your back flushing tee. Also disconnect your overflow tank hose.

3) After the radiator is drained, take off the radiator cap.

4) Get your garden hose and screw it onto your back flushing tee connector then put the connector to the back flushing tee you installed..

5) Turn on the water and wait for water to start coming out of both the radiator drain and top radiator opening.

6) Turn on your engine with your heater running on high and let the car back flush for 30 minutes.

7) Turn off the engine and disconnect your garden hose.

8) Wait for the water to drain completely from the radiator.

9) Close the radiator drain c*ck.

10) Pour in your bottle of Zerex Super Cleaner into the radiator.

11) Connect the overflow tank hose and top off radiator with water.

12) If you have bleeder valves for air, turn the engine on with the valves open and wait for water to come out of them in a constant stream then close the valves.

13) Drive your vehicle for 4 - 6 hours which can be on and off and over a few days. Be careful the outside temperature is not 32° F or lower as water expands when it freezes which will ruin your radiator and your engine and other components.

14) Repeat steps 1 - 12 except for step 10 pour in your bottle of Zerex Super Flush.

15) Run engine for 15 minutes.

16) Repeat steps 1 - 9.

17) You may want to take out your overflow tank and scrub it inside and out with dish soap and a bottle brush. Be sure to rinse all the soap out of it. When you install it back into your vehicle, you may want to fill it up with water from your garden hose a few times and let it drain out through the disconnected overflow tank hose.

18) Connect the overflow tank hose after the overflow tank has been rinsed and is completely empty.

19) Pour in your jugs of Zerex 5/100 Coolant slowly until the radiator is full of coolant. If it takes 1 1/2 jugs, then that is 6 quarts. If your system holds 12 quarts, then you have a 50/50 mixture.

20) Fill the overflow tank with Zerex 5/100 Coolant until either the overflow tank is half full or you reach the HOT line.

21) Repeat step 12.

22) That is pretty much it, but be sure to check your overflow tank and keep the coolant level at the COLD line after your vehicle has sat for 6 or

8 hours over the next few days and get into the habit of checking it at least once a week.

Hopefully Helpful,

BTJustice

Reply to
Buford T. Justice
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An excellent and informative post. You couldn't get me to touch Dex-Cool with a 50 foot pole due to some of the horror stories I've heard, but never seen anyone describe the hassles in any real detail. Thanks!

Reply to
FBR

OH NO! FBR you crossposted. Does that mean I have to report you to your isp? Lol Jk

From my experience only use dexcool on a dexcool system only. The cooling system isnt designed to handle the kind of deposites left behind by regular coolant. Dexcool works great if you follow 2 simple things. Dont contaminant it and dont let it take in air. Keep the overflow bottle filled to the hot mark with a clean mix and it shouldnt give ya any problems.

Reply to
Bon·ne·ville

That was what I was shooting for. Hope it helps you and others.

BTJustice

Reply to
Buford T. Justice

I heartily second your recommendation NOT to use Dex-Cool. In my sad experience with several cars, it greatly hastens corrosion and plugging of cooling system components and attacks numerous different gasket/seal materials.

Green stuff is fine, G-05 is probably better. But no more Dex-Cool in my vehicles, ever.

DS

Reply to
Daniel J. Stern

I disagree...

If you flush thoroughly with a chemical cleaner (Zerex Super Cleaner), it is safe to go to green but follow the steps in my original post.

It is almost impossible to not let coolant take in air. It gets nice and steamy inside the engine cooling system after awhile. Plus the coolant in the overflow is always in contact with air due to the open overflow hole on most of the overflow tanks.

It is almost impossible to avoid contamination. Wait until you go to a Jiffy Lube or equivalent and they top off the DEX-COOL in your overflow tank with conventional green. It only takes one stupid kid working part-time.

BTJustice

Reply to
Buford T. Justice

Yes, that was a very good post...Now should I be a little bit worried with my 2001 GMC Safari, and 2000 Impala with Dexcool...I have basically thrown GM's 160,000 km recommended change frequency out the window and decided to go to 80,000 kms change frequency on Dexcool...Its not that expensive to change...Would you do the conversion process instead or live with it? Steve "Buford T. Justice"

Reply to
Skeezicks

Gotta go with your gut, but lots of people have done it without any problems that I know of thru numerous hours of research on DEX-COOL. Be sure to follow the steps in my original post.

BTJustice

Reply to
Buford T. Justice

There is a problem with your theory. Dex-cool is a specific style antifreeze in that the whole entire system has to be designed for it. It is like trying to run R134a freon in an R12. Of course you are going to get all kinds of grief with gaskets and the such. The basic chemical composition of Dex-cool and a traditional glycol antifreeze are very different. Also, there is nothing wrong with running a coolant that is long life for a longer period of time. As long as you check the coolant from time to time for discoloration from contamination and the such, you will be good to go. New semi's that have engines worth as much as a new truck use this type of long life coolant as well.

"Buford T. Justice"

Reply to
Joe Poitras

On Sun, 5 Oct 2003 04:30:23 -0500, "Buford T. Justice"

Reply to
TJ 727

I have read about this sometime ago and here is information that may be beneficial to everyone. I guess there is pro's and con's for everything. So the pro's is DEX-COOL offer excellent heat transfer capability thus if it is done properly. Check out this reference article

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con's perhaps it is does not last as long as expected. Also, there isa big class action pending with GM right now about this ....Here is the links for your reference.http://www.bigclassaction.com/class_action/dexcool.html and this one .
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Myself I would probably not convert back but replace the DEX-COOL regularly (may be every 3 years or less under extreme climate)

MN

"Buford T. Justice"

Reply to
MN
98 bonneville 75k miles (5 year old coolant until just recently), Clean as hell coolant and overflow bottle. I pulled both my upper and lower intakes to repair a leak caused by the egr pipe and the cooling passages had NO oxidation, coatings, or sludge what so ever. The metal was as bright and shiny as the day it was assembled.

If its a silica based coolant it will eat up the aluminum components. Also the temp sensor is balanced to read a dexcool system. It may not have the resistance to the coating that green coolant leaves on everything. Though they make mistakes in designs now and then do you really know more about the cooling system than the GM engineers that designed it?

There is no steam in a correctly filled cooling system. You dont understand what I'm saying, I'll try my best to explain everything I have experienced and read about. Air in the overflow bottle wont muddy it. Its intense heat and low coolant levels that cause the coolant to crystalize. Basically when theres air in the system its cooking the coolant. Put salt water in a saucer and let it evaporate and you're left with salt crystals coating the saucer. Basically the same thing happens to dexcool and thats why it looks muddy because of air in the system and "intense heat". When you put non distilled water or another substance in the coolant it causes the chemicals that make up dexcool, to the best i can tell, fall out of suspension or to latch onto the contaminates or the sludge is the contaminate. If you're overflow bottle is muddy it was contaminated or your cooling system is low. When its low air is in the system and steam now builds up and pushes the coolant into the overflow bottle. Then all that crystalized coolant clogs up your radiator cap and what went into the overflow bottle doesnt make it back in so it tricks you into thinking your system is full. Thats why you need to uncap it now and then just to make sure its really full.

I do my own maintenance so its not impossible for me. Do what I do, keep it filled to the hot line when the engine is cool. GM is actually recommending that in their service bulletins. If some shop contaminates your cooling system pursue them in court if thats what it takes to correct that problem.

I got a website marked somewhere that covers dexcool and other coolants pretty well. If I come accross it in the next few days I'll post it. Dexcool is getting a bad wrap by people who dont try to fully understand it or dont maintain there systems correctly. If you never EVER contaminate an "original" dexcool system it wont get muddy. If you dont ever ever let air into the "COOLING SYSTEM" (not the overflow bottle) it wont get muddy.

You mentioned you tried to upgrade cooling systems that never originally had dexcool. The only possible chance that could have maybe worked is if the system was acid flushed repeatedly. Even then it would still be iffy.

Reply to
Bon·ne·ville

On Sun, 5 Oct 2003 05:26:31 -0500, "Buford T. Justice"

Reply to
TJ 727

OMG I did crosspost! I am unworthy to live. Unworthy! Unclean! EVIL! ACK!

Reply to
FBR

It is not a theory. They are simple "real-world" facts.

Not really. The cooling systems are physically no different. The coolant goes from the radiator thru the engine, transmission, and heater core and then back to the radiator.

This is a bad example. R134A and R12 do require 2 completely different systems to run. DEX-COOL and conventional green do not require different cooling systems and have the same chemical compostion which is ethylene glycol. DEX-COOL uses organic inhibitors and conventional green uses inorganic inhibitors.

Yes there is! As long as no more water or antifreeze is added to a cooling system, the freeze point is permanent, but the boilover and and protection points do change.

Yes and no. Semis do have a long life coolant, but it is only good for approxiamtely 300,000 miles in which it is time to rebuild the semi engine. If hte engine is fine, then they pour in a bottle which extends the life of the coolant.

BTJustice

Reply to
Buford T. Justice

Glad to hear DEX-COOL is working fine for you. Others are not so lucky.

I have yet to see a green coolant sold at any major auto supply store that does not protect aluminum. The temp sensor doesn;t care what is in the cooling system. It simply monitors the temp of what is in the cooling system. Try running just straight water and you will see the temp is the same, but he water will start rusting your aluminum components. Texeco was the primary engineer of DEX-COOL.

Yes there is. How does a radiator cap open to let excess coolant into the overflow tank? Magic?

Now that is good advise. It is important ot remove the radiaotr cap from time ot time to be sure the radiator is actually full.

Keep the overflow filled to the HOT line on a cool system? That should tell the GM engineers are on crack.

DEX-COOL is getting a bad rap because GM didn't do enough real world tests on it. The simple truth of the matter is if DEX-COOL is in direct contact with air in one way or another then you will get mud. As I said, wait to a tennager at Jiffy Lube tops off your empty overflow tank with green. Do you really thing they will take your radiator cap off to look and see what type of antifreeze your are running? How about NO!

Super Cleaner being ran for 4 - 6 hours ring any bells? I and many uninformed people converted to DEX-COOL thinking it would last longer and be a better choice. Man were we wrong.

BTJustice

Reply to
Buford T. Justice

They were until GM had a recall on the 3800s. Then another recall on the intake manifold gasket bolts. Crazy stuff.

You probably didn't take any long vacations in that feat of engineering, lol.

BTJustice

Reply to
Buford T. Justice

The coolant never goes thru the transmission.

The transmission fluid goes through the lower part of the radiator for some cooling effect. Some cars have a separate tranny fluid radiator for cooling, called atf cooler.

Reply to
Daniel

"Buford T. Justice"

Reply to
Stephen Bigelow

"Buford T. Justice" wrote

No, it's not magic, but it's certainly not steam. It's simply the fact that the coolant expands as it heats, the rad cap is set to maintain 15 lbs of pressure in the system, once pressure goes past that, the cap unseats itself and allows coolant to flow to the overflow tank. Pretty simple stuff actually, no steam or magic involved.

Not really, it's just their way of trying to ensure that the cooling system does not get air into it for a longer period of time. The air in the system is really only a problem with any of the engines that have a cast iron block, or heads. I've seen very few if any sludging problems with the all aluminum engines. Also the vehicles that use a radiator cap, and a separate non-pressurized overflow tank seem to be the most susceptible to the sludging problem. I've seen very few problems with the vehicles that have the hard plastic pressurized overflow tank that has the 'rad' cap mounted on the overflow tank not the rad.

Of course, this is really more the fault of stupid customers that take their vehicles to a place like Jiffy Lube. And the problem is not Dexcool in direct contact with air, it's a cooling system that is allowed to be run at a low level for an extended period of time with an engine that has at least a cast iron block.

I don't believe that GM ever recommended changing to Dexcool on older cars.

By the way, I'm not a big fan of Dexcool. I work with vehicles that use it all day and I've come to the conclusion that it cannot be relied upon to last as long as GM says it should. We now advise people to change Dexcool at about the 100K kilometer mark, or every 3 years. This seems to work well, and cuts down on the incidence of cooling system problems with Dexcool.

Ian

Reply to
shiden_kai

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