Dexron Antifreeze mixing

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I have a 1997 Buick LeSabre. I has the orange Dexron coolant. The car was not blowing heated air, so I checked the radiator. The coolant level was very low, so I put in some green Texaco coolant. Can I mix Dexron and regular antifreeze, or will I blow my engine?

The car is in the repair shop for the coolant leak, but I want to know for the future.

Thanx

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Vito wrote:

(1) Do you mean orange Dex-Cool coolant? (2) Your heater may not have been blowing hot air since there was an air bubble, due to the low coolant level. (3) Mixing Dex-Cool with ordinary coolant is not wise. It won't blow the engine, but you will have a big gummy mess pretty soon. If this is what you did, then it would be best to flush the whole works, chemically rinse the whole works, and then refill it with proper coolant. You can use Dex-Cool, or you can use ordinary coolant, but don't mix them.

---Bob Gross---

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Vito,

Mixing Dex-Cool and green coolant is not recommended by GM. But the green coolant can be added, when you are in a bind, and you don't have Dex-Cool. It will not harm the engine, gel, or gum-up, as Bob has stated. It will however reduce the life of the coolant, to that of the green coolant.

When you have your mechanic repair the leak, have him flush the cooling system well, and re-install the Dex-Cool. No chemical flushing is needed, or advised. Both coolants are of an ethylene glycol base. Dex-Cool has a longer life, and is better for the environment.

I received the above information, from an instructor at the GM training facility, in Hinsdale, IL, while taking a course. His information came from an engineer in Detroit.

This myth of gelling-up, or gumming-up, is just that. A myth.

GMdude

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GMdude wrote:

However, it is a well-observed myth.

A close relative purchased a one-year-old GM car with orange Dex-Cool in it. It looked clean and orange when he got it, but the level looked low, so he dumped in some green normal coolant. Next think he knew he had a brown mess, kind of frothy and bad. He did some checking around, and that kind of mixture problem seemed to be well known.

---Bob Gross---

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Bob,

Dex-cool has been known to leave brown deposits in the recovery tank, and at the radiator cap. That dose not mean there is a problem. Green coolant also leaves deposits. They are usually light-green/white in color. So what?

Any dye will leave some sort of residue. The green coolant isn't green until the dye is added. The Dex-Cool isn't orange until the dye is added. It's the dyes that leave a residue in the cooling system.

The dyes will not harm the engine. Even if they mix and make some nasty color, the coolant is still OK.

It's not a well known problem. It's a well circulated myth. It might make a nasty color, leave brown stains, but it doesn't effect cooling, or the engine.

GMdude

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Bob,

When it comes to colors/dyes. When you mix orange with green, you get brown.

GMdude

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GMdude wrote:

NO JOKE!

That wasn't the issue. I think you missed my point. The question was what was going on when you mix clear, orange Dex-Cool with clear, green normal coolant, and shortly later you get this frothy mess. If it were clear and brown, that would not be too surprising.

---Bob Gross---

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Bob,

Hey dude. I'm giving you the GM facts. I've added the green stuff to orange, when the orange was not there. I found no froth, as you put it, and no problems with cooling. I worked for GM for 10 years, and now work for a municipality. I maintain a fleet of 126 vehicles, along with 3 other mechanics.

These vehicles vary from cars, to 40 foot transit buses (diesels). I doubt there is much you can teach me about coolant.

I currently have access to all GM service bulletins, which state nothing to the contrary, of what I have stated here.

If you can show me any shred of evidence about this stuff causing engine problems, when mixed with green coolant, then do so. Meaning GM documentation.

Froth in a cooling system is usually a sign of a petroleum product mixed in. Oil, trans fluid, etc...

GMdude

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This is a multi-part message in MIME format.

------=_NextPart_000_0051_01C3D99D.825EA740 Content-Type: text/plain;     charset="Windows-1252" Content-Transfer-Encoding

I too work for GM as a partsman. I found this on Dex-cool from GM Infonet.

Date Created: 02/21/2003 Last Updated: 01/13/2004

Author: Gayle Timmons/MINACSGM/CA

Reference: TAC TIP

Reference #: TT742

Document Title: COOLING SYSTEM ADDITIVES ON VEHICLES WITH DEX-COOL ENGINE COOLANT - TT742

Condition:

Cause:

Correction:

DATE: FEBRUARY 21, 2003 TO: ALL GENERAL MOTORS DEALERS ATTENTION: SERVICE MANAGER/SHOP SUPERVISOR/ PARTS MANAGER C: ZONE - ASSISTANT ZONE MANAGER - SERVICE ZONE - DISTRICT SERVICE MANAGER ZONE - DISTRICT PARTS MANAGER SUBJECT: TT742 - COOLING SYSTEM ADDITIVES ON VEHICLES WITH DEX-COOL ENGINE COOLANT VEHICLES AFFECTED: ALL VEHICLES EQUIPPED WITH DEX-COOL ENGINE COOLANT FROM: P.C. BAGNALL, GENERAL DIRECTOR, CUSTOMER SUPPORT SERVICES ISSUED BY: RICHARD HORSLEY, SERVICE ENGINEER, TECHNICAL SERVICES DEPT. FOR FURTHER INFO: TECHNICAL ASSISTANCE CENTRE - 1-800-XXX-XXXX - GROUPS 2 & 3 __________________________________________________________ ***DISCLAIMER***

GENERAL MOTORS SERVICE INFORMATION MATERIALS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A 'DO IT YOURSELFER'. THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE INFORMATION APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

CONDITION:

Use of Cooling System Conditioners, Stabilizers or Additives not required with DEX-COOL Engine Coolant.

CAUSE/CORRECTION:

Since 1996 most General Motors vehicles were produced with DEX-COOL long life engine Coolant. DEX-COOL, if properly maintained, will protect the engine cooling system components for a period of 5 years or 240,000 KM, which ever occurs first. This service interval will be met if the cooling system is properly maintained in the following three areas:

1. The cooling systems freeze protection and level must be maintained to prevent deposits from forming in the voids of the cooling system. Proper coolant strength and level are critical to preventing the formation of rust-like deposits in the cooling system. 2. DEX-COOL must not be mixed with conventional "Green" coolant. Mixing coolants will remove the extended life properties and require that the coolant be replaced or recycled at a 2 year/50,000 KM service interval. 3. The radiator cap must be maintained and tested on an annual basis as outlined in the vehicle maintenance schedule. A properly functioning cap ensures the cooling system pressure requirements are met as well as maintains proper cooling system level by allowing coolant to transfer between the reservoir and radiator.

Some companies are promoting products such as Conditioners, Stabilizers or Additives, which are claimed to improve or extend coolant performance or life. General Motors does not support or recommend any products, which do not meet General Motors specifications. The use of these products may degrade the cooling system and any resulting failures would not be covered by the General Motors New Vehicle Limited Warranty.

The vehicle owners manual section Service and Appearance Care, contains the following statement on cooling system additives: "Notice: If you use proper coolant, you dont have to add inhibitors or additives which claim to improve the system. These can be harmful."

Proper cooling system maintenance and flush procedures are covered under Product Service Bulletin 06-02-006 DEX-COOL Engine Coolant Information

Previous Product Service Bulletins were released to assist technicians in identifying some cooling system conditions that were incorrectly diagnosed as a failure of the DEX-COOL coolant. These are:

1. PSB 99-06-02-012D - Relating to certain 1996 - 2000 S/T Pickups and Utilities with the 4.3 Litre V6 engines which were operated with a low coolant level. 2. PSB 01-06-02-003 - Relating to certain 1996 RWD Chevrolet Caprice, Buick Roadmaster and Cadillac Fleetwood with a 4.3 Litre or 5.7 Litre V8 Engine which could experience excess aeration of the coolant. 3. PSB 00-06-02-004 - Relating to certain 1996 - 2000 vehicles with 3.1 or 3.8 Litre V6 engines, which are operated with a low coolant level. 4. PSB 00-06-02-005 - Relating to certain 2000 Buick LeSabre or Pontiac Bonneville Models which could have excess deposits from coolant sealer pellets.

--

Sincerely, Alan Ralston

--
GM Partsman
Owner of Pure Performance Fever
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On Monday, January 12, 2004 10:22:55 PM UTC-5, GMdude wrote:

http://www.bigclassaction.com/settlement/general-motors-dexcool-antifreeze.php

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John Tolman wrote:

"The company, however, stated that in agreeing to settle, they don't admit any liability and that they believed that Dex-Cool protected engines for longer periods than traditional coolants. Company spokespersons said that the coolant caused less wear on certain engine parts and provided various environmental benefits. They also claimed that owners who experienced engine and cooling system problems had not followed maintenance instructions. "

--
Steve W.

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The only thing I have ever seen from GM on mixing coolants was that is acceptable to mix them BUT that it degrades the Dex-cools "Extended Life" and meant that you needed to switch to the maintenance intervals for the green coolant.

99% of the "coolant caused" gasket failures are NOT due to the coolant. They are due to the piss poor gasket design combined with the poor clamping of the parts. The SBC didn't have gasket failure issues till the switch to the Gen 2 head/intake designs. Many people claim the 4.3 / 5.7 intake gasket failures are due to Dex. Nope they are due to plastic gaskets and lack of even clamping forces.

--
Steve W.

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Robertwgross wrote:

The brown stuff has nothing to do with mixing in other coolant. It is an issue with the Dex-Cool and has happened in several instances. The main cause seems to be running too low on coolant.

You did not say what year that car was. There were problems with some of the 1999 models. Perhaps some materials used in the engine were not compatible with the coolant but GM has denied any connection. In all cases they say that proper maintenance was the issue.

Problems seem to be especially bad with Dex-Cool when the owner lets the level get too low or top off with water instead of a coolant mixture.

Some brown stuff that has been seen comes from leak preventatives.

It is important that you have Dex-Cool you should make certain the over-flow tank is full at all times. Of course that is important with all coolant but especially with Dex-Cool.

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From what "I've experienced" and have seen the conventional green coolant attacts aluminum towards the end of its life cycle vigorously. I've seen some pretty bad pitting on machined mating surfaces of aluminum. I've also seen hardened clusters of silicon bonded to aluminum surfaces. The silicon contained in green coolant isnt the healthiest stuff you can put in a modern cooling system. As the coolant ages the silicon tends to bond to each other forming larger particals and it begins to eat away at aluminum like a sand blaster. The aluminum pipes on heater cores seem to often fail because of this. (my theory) When ever you put a silicon based coolant in your cooling system you must and I mean MUST change your coolant every 2 years. Even if you try to switch back to dexcool. I can look at a system that has had green coolant in it and it is coated with scaling even from short term use. That coating "prevents" dexcool corrosion inhibitors from effectively lasting more than 2 years. Now as for dexcool sludge/foam/mud, the best cure for that seems to be this. KEEP air out of your system, Keep your radiator cap clean, Keep your overflow bottle filled to the highest mark, and use only distilled water with 50/50 mixes. Those 4 things I found seem to help out a lot. Keep in mind that just because a cooling system says 5 years 150k miles doesnt mean you can ignore checking the system that long! Check it weekly and monitor for any coolant loss and if there is any find where its going and fix it. If you cant find GM dexcool the best alternatives are silicon phosphate free coolants. Avoid putting anything in the system containing those 2 things. Prestone and Havoline both make coolants that are compatible with dexcool but arent exactly dexcool. GM only mentions Havoline as having a coolant compatible with dexcool. So if you in a bind or you dont want to buy dexcool try those out. One more note to add, I think if you have both types mixed in a cooling system the corrosion inhibitors attack eachother shorting the life of the coolant much sooner than 2 years. So keep that in mind.

snipped-for-privacy@noplace.net says...

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Bonneville wrote:

Surely you are referring to silicates, not elemental silicon.

---Bob Gross---

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snipped-for-privacy@cs.com says...

Silicate would of probably been more correct if not more correct sounding but its basically all the same in the end. Silica, silicate, silicon if its not the same then whichever form of it if they put in the green coolant will eat aluminum up. Silicate crystals can clump together and do a number on the system through erosion. Iron can handle it just fine but aluminum which is found more and more doesnt like it very well. Thats one reason for so many new coolants out on the market now. Anyhow the whole green coolant/dexcool coolant debate has been going on for a long time...and so will this thread most likely.

http://dictionary.reference.com/search?q=silicate

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I was thinking that pure silicate-based coolants do not corrode the aluminum system if everything is clean, but over a period of time, combustion byproducts and other *crappy* acids get into the coolant. That acidic blend is what makes coolants go bad, and that is why coolants are recommended to be replaced periodically. However, that is my thought, and I don't fully understand the detailed chemistry going on in there.

---Bob Gross---

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I read an artical in motortrend that said the new coolant has an acid in it for aluminum radiators and if you use it on older ones it will eat up the solder joints over time---they didn't say how long or what concentration--probably 100%--I haven't seen anything from gm on this though----

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There is an awful mess of (mis)information surrounding this issue. I have read technical information from the proper sources that do say there is no problem inherent to mixing Dex and green (other than decreased expected life). I have, however, seen to many instances of brown cottage cheese in vehicles that were running mixes. Some sources indicate that this is coincidental, and actually due in part to faulty/improper radiator caps. This is one issue, however, that I personally would just not be comfortable accepting manufacturer's information. It's just my own peace of mind (for my own cars and in respect to comebacks) to never mix.

On Mon, 12 Jan 2004 16:58:02 -0700, GMdude wrote:

--
remove 'spamsucks' from mail addy for replies.
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I agree. My uncle is a manager of a garage around here and he says that every now and then someone comes in wanting a coolant flush/refill and he said something about putting dex-cool and antifreeze together in one container for the waste people to get rid of. But at the bottom of this container there was hardened stuff that he needed to chip away and since then they've been using 2 containers, the problem hasn't happened since.

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