Mix dex cool with green antifreeze?

Canary2323

Original poster
Member
Mar 31, 2012
346
Was getting my tires rotated at a local shop and I noticed my coolant seemed low so asked the guy to top it off after the tires. But I noticed he added regular auto zone antifreeze in it. Then I checked it out later and seen that it says use dex cool only, so I Google it and saw different answers. I'm I Ok or do I need to flush and replace with dex or just regular antifreeze. Help please..
 

RayVoy

Member
Nov 20, 2011
939
AFAIK, all antifreeze solutions can be mixed (same chemical class). The resulting mixture will not harm the cooling system. However, the addition of regular antifreeze to Dex Cool will reduce the long term integrity of the Dex Cool; you have, effectively, reduced the Dex Cool to the change interval of the regular antifreeze.

You will hear, and read, some horror stories about mixing the two, and resulting in coolant leaks into the engine. GM (and, notice I said GM) claims the leaks result when the owner has not kept the coolant at the normal level. GM claims that when Dex Cool is exposed to air inside the hot engine environment, the resulting chemical change will cause the gaskets to leak. GM claims they have solved the problem by using different gasket material.
 

MAY03LT

Member
Nov 18, 2011
3,422
Delmarva
Are you sure that he added green stuff? At my work I have EG, dex, g05, g12, toyota long life, etc, each in identical containers.
 

Canary2323

Original poster
Member
Mar 31, 2012
346
Yeah I read some horror stories that why got me worried, so I should be Ok?
Yeah I saw the stuff he used, I just didn't notice that you had to have a certain kind of antifreeze in gm's.
 

Mark20

Member
Dec 6, 2011
1,630
As I understand it you can not mix traditional green and Dex-Cool. Can I Add the Green Coolant to the Orange Coolant?

Now there are some versions of anti-freeze that can be mixed with either but I am not sure what color they are dyed and I have not used them. You'
ll want to check what the shop used.
 

gmcman

Member
Dec 12, 2011
4,656
Take it back and have them flush it out and refill with dexcool. Also tell them you want in writing what they did.
 

Grimor

Member
Mar 28, 2013
954
Canary2323 said:
Yeah I read some horror stories that why got me worried, so I should be Ok?
Yeah I saw the stuff he used, I just didn't notice that you had to have a certain kind of antifreeze in gm's.

I never had a problem mixing antifreeze, but I've had problems mixing washer fluid. Rain-X and some blue junk seems to form a weird jell
 

eutechnyx

Member
Mar 31, 2012
375
I've always read and been told mixing dexcool and regular antifreeze produces a sludge in the cooling system.
 

TangoBravo

Member
Dec 5, 2011
208
eutechnyx said:
I've always read and been told mixing dexcool and regular antifreeze produces a sludge in the cooling system.

Happend to my mom, she took her truck to a shop and they topped it off after a service with the dredded green stuff. Bout 6months later she started having overheating issues. Turns out her cooling system was full of a wonderful sludge. $1300 later it was fixed. The shop covered the cost but still it could have all been prevented by ONLY USING DEX COOL as it states all over on a chevy and it says it for GOOD reason.
 

Canary2323

Original poster
Member
Mar 31, 2012
346
I probably could.. But never have before. Might just schedule a service place to have it done on Monday. I thought I was just flushed system and good to go.
 

gmcman

Member
Dec 12, 2011
4,656
This happened to a buddy of mine last week when we were going to change the t-stat. We showed the shop the orange dexcool still in the reservoir and the green in the radiator.

We also told them to put in writing what they did this is important and also mention to them if they are hesitant to change it out that you don't want to come back later with a plugged up heater core because of the mix of coolants.

Nobody wants to change a heater core.

They were cool about it.
 

AbsoluteZero

Member
Nov 21, 2011
211
I bought some Walmart Super Tech 50/50 antifreeze to top off my daughter's non-Dexcool car. The container is labeled "... is recommended, compatible and formulated for use with ANY antifreeze in ANY make or model car or light duty truck with aluminum or other engine metals...... " The container also shows " Extended Life Up To 5 years or 150,000 miles..."
It doesn't have any reference to Dexcool but sure sounds like it. In fact other coolant brands Walmart carries now have this same verbiage.
I haven't specifically looked but I haven't seen the green stuff for several years.
What does seems strange is the pre-mixed 50/50 Dexcool is about $12/gal or the non-diluted stuff is $14/gal. So if you need 2 gals it's $24 using the 50/50 mix or about $15 using the pure stuff. Assuming less than $1 for a gal. of distilled water. Maybe that's why it's hard to find 100% on Walmart's shelf!
 

Canary2323

Original poster
Member
Mar 31, 2012
346
The stuff they used said universal any color, and extended life 150,000. From what I've Googled about mixing/compatibility I'm still confused haha. I scheduled a complete flush this week just for peace of mind.
 

TangoBravo

Member
Dec 5, 2011
208
Canary2323 said:
The stuff they used said universal any color, and extended life 150,000. From what I've Googled about mixing/compatibility I'm still confused haha. I scheduled a complete flush this week just for peace of mind.

Yeah it is supposed to be universal. However your vehicle calls for dex cool only, not dex cool or/and universal. As said here before you really should never use anything but dex cool in our trucks.
 

blazinlow89

Member
Jan 25, 2012
2,088
AbsoluteZero said:
I haven't specifically looked but I haven't seen the green stuff for several years.
What does seems strange is the pre-mixed 50/50 Dexcool is about $12/gal or the non-diluted stuff is $14/gal. So if you need 2 gals it's $24 using the 50/50 mix or about $15 using the pure stuff. Assuming less than $1 for a gal. of distilled water. Maybe that's why it's hard to find 100% on Walmart's shelf!

Its impossible to even find 100% around here. Every thing at auto zone, advanced and the local places is 50/50. They say its easier as most people had issues with the 100% because they did not dilute it. I have found it at one NAPA before, but for them to have it takes a miracle.
 

gmcman

Member
Dec 12, 2011
4,656
blazinlow89 said:
Its impossible to even find 100% around here. Every thing at auto zone, advanced and the local places is 50/50. They say its easier as most people had issues with the 100% because they did not dilute it. I have found it at one NAPA before, but for them to have it takes a miracle.

Actually it works out better for most since the premix uses distilled water, which is what you should always use if you mix it yourself.

All my local NAPA's have 100% and CARQUEST carries it as well I believe.
 

blazinlow89

Member
Jan 25, 2012
2,088
gmcman said:
Actually it works out better for most since the premix uses distilled water, which is what you should always use if you mix it yourself.

All my local NAPA's have 100% and CARQUEST carries it as well I believe.

I guess that's the good thing about having a saltwater aquarium, I always have distilled water on hand. Cheaper than a RO/DI filter, and I do not have a huge aquarium so it is manageable.
 

gmcman

Member
Dec 12, 2011
4,656
I have always used distilled water for my coolant changes for the envoy, but after researching a little it appears the DexCool is more tolerant to hard water so tap water apparently is ok....which is a good thing.

The thing is, if the vehicle wasn't built around the heater core I would feel better but that's just one part of the equation. I have had DexCool in this motor for 11 years and never a problem..knock on wood. Keep up on the service and you should be fine.

For reference, this is from the owners manual:

Engine Coolant

The cooling system in your vehicle is filled with
DEX-COOL® engine coolant. This coolant is designed
to remain in your vehicle for five years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX-COOL® extended life coolant.

The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, see Engine Overheating on
page 5-26.

A 50/50 mixture of clean, drinkable water and
DEX-COOL® coolant will:

• Give freezing protection down to −34°F (−37°C).
• Give boiling protection up to 265°F (129°C).
• Protect against rust and corrosion.
• Help keep the proper engine temperature.
• Let the warning lights and gages work as
they should.

Notice: Using coolant other than DEX-COOL® may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs first. Any repairs
would not be covered by your warranty. Always use
DEX-COOL® (silicate-free) coolant in your vehicle.




This kind of puts the ball in your court if you fill it with green and have issues.
 

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