changing coolant on 2007 2500HD

[jbres]

Have a question regarding changing coolant on my truck.
(truck is a 2007 gmc sierra 2500HD classic 2wd w. 6.0 gas job)
I had a gift card to Tire Discounters so took my truck there today to get a coolant flush/change. I told them I wanted it changed with something "dex-cool" approved as it states in my owners manual. Guy behind the counter says we use "Valvoline Max Life" which is a universal green antifreeze that mixes with any color and can use on any car or light truck.
Antifreeze I had in my truck was red and still in there from factory with 68,000 miles.

My question is was I wrong with letting them use the "Valvoline Max Life" as a substitute? It technically I guess isn't "dex cool approved" but also is universal, so is confusing me. I am trying to debate whether or not I need to get out the coolant they put in, and make sure to get back in the dex cool. Guy behind the counter actually said he would never use dex cool in any of his vehicles.
Any opinions or suggestions, I am trying to do some preventative maintenance and avoid head gasket failure years from now.
Thanks!

[LarryJM]

jus2shy wrote:

#1Flyboy wrote:
. . .Silica fallout is usually found in OLD antifreeze( REALLY OLD!!! ) & usually in Diesel engines IF not keeping up with their nitrate levels/ coolant filters. . . NOT an issue with todays coolants as they are formulated (When is last time in last 10 years anyone saw silicate fallout?). . .I worked a successful automotive cooling system shop (33 years) & yes, actually purchased FULL trailer loads (20 pallets) of coolant at a time. . .Only took a few classes on coolants & such but had 43 years in cooling systems industry addressing & solving problems with cooling systems. . .Also talked to several AC Delco guys(at trade shows) about their Dex-Cool problems & every one of them had a different answer. . .By the way your link did not work.. . .YMMV. . .

Well, silica fallout still happens today and forms goo. Here's what happen when you take the coolant from a 2012 chrysler vehicle using a HOAT and mix it with 5% or more of the new OAT (AKA Grapejuice) that chrysler is using in a 2013 vehicle: http://starparts.chrysler.com/newsletters/newsletter_Oct_2012.pdf It's a PDF, so you need to have a PDF viewer to see this as with my last link. Seems to work fine for me anyways. On page 4 of the print, you can see the results of the mixing. This alone disproves that all coolants are compatible with one another.

Some coolants do have wide compatibility, but when you mix coolants, you are always diluting their additive package and I am not a chemist, so I can't tell you what would happen if you mix brand x with brand y. That's why I personally believe in following the manufacturer specs.

Also, Japanese auto makers tend to use a phosphated anti-freeze, primarily because of the intense use in aluminum and such, along with the quick development of that "film" that protects and coats all the parts quicker than a normal OAT. Then Daimler still uses a Silicated anti-freeze. Mix that Silicated with certain OAT anti-freeze and you can run into more of the gelling issues. Another reason why I'm really careful about anti-freeze selection.

However to the OP, I reviewed my coolant notes while at work today. If you did have a full flush in the system and have less than 5% of the old anti-freeze mixed with the new antifreeze and what they used is a universal coolant. You may be able to get away with it. However, you'd still want to flush fairly early compared to the normal 5yr/150k miles that I believe GM recommends for Coolant replacement.

Really the issue is mixing of coolants. However, even though people call it "Deathcool", I think it earned that name due to its early implementation and not understanding the full properties of OAT coolants, especially the 2-eha that's in DEXCOOL. That tends to soften certain seals and types of plastics overtime. Personally, I like that Chrysler's new OAT doesn't use 2-EHA so I'm hoping I don't have the issue with my motor in the future but I will still watch it.

If you're bored, here's a good article on Coolant in general, it goes through why certain packages are in certain coolants and such and may open your eyes to who uses what (and yes, this is a professional rag) (although it's titled to talk about Chrysler's coolant switch): SAE Coolant Article

Thanks for this information and I was unaware that both Ford and Chrysler (I guess MB/Daimler has decided to stay with the HOAT coolant) had switched from their HOAT coolants to the more traditional OAT type coolants so the information in my prior post is somewhat dated. That SAE link was especially enlightening and informative. I can understand the reasoning for the switch since the OAT type coolants as I previously stated do have a longer change interval than the HOAT coolants. I have two vehicles, a 2001 Sebring with the 3.0 Mitsibushi engine and a 2001 Ford 7.3L diesel both of which use G-05 and have been using that coolant in them for some years (I switched the 7.3L from the old IAT green with SCAs to the G-05 back in around 2004). I also have a 2013 Hyundai Sonata LTD. that I don't have a clue on what type of coolant it has so I guess I need to do a little more homework to learn about that one since there is now a plethra of coolants used across the vehicle spectrum which tells me it's even more important to pay attention to where and how you have your coolant system serviced since even the slightest inattention to the details can result in HUGE PROBLEMS.

Larry

[MARKW8]

Any real problems with Dexcool were 10+ years ago. GM was using plastic intake manifold gaskets that were going bad and being blamed on Dexcool. I had an 03 S-10 PU with the 4.3 V-6 that needed new intake gaskets at 50k. My son has the truck truck now with north of 160k, still with Dexcool.

Mark

[jbres]

didn't realize there was a class action lawsuit again GM and dexcool in 2008. Also, my friend from work said he wont ever use Dex cool again. He told me to go look at my other vehicle which is an 2003 Tahoe, and look at the film in the coolant tank. Sure enough, he was correct. Film build up in the coolant tank is present in my 03', even after I flushed it back in the fall.

[MARK_VANDERBENT]

You did good !! new dexcool would have been fine, but the Valvoline is good too. Both do their job !!

[jbres]

After talking with a very reputable mechanic I know, he tells me its almost a better idea to use the yellow/green universal Valvoline antifreeze that I have in there than to go back to Dex-cool. He has seen to many problems with Dex over time.
Also, spoke with Valvoline and they stand 100% behind how this "universal green/yellow" will actually mix with any color antifreeze and they stand 100% behind that.

[jus2shy]

#1Flyboy wrote:
. . .Silica fallout is usually found in OLD antifreeze( REALLY OLD!!! ) & usually in Diesel engines IF not keeping up with their nitrate levels/ coolant filters. . . NOT an issue with todays coolants as they are formulated (When is last time in last 10 years anyone saw silicate fallout?). . .I worked a successful automotive cooling system shop (33 years) & yes, actually purchased FULL trailer loads (20 pallets) of coolant at a time. . .Only took a few classes on coolants & such but had 43 years in cooling systems industry addressing & solving problems with cooling systems. . .Also talked to several AC Delco guys(at trade shows) about their Dex-Cool problems & every one of them had a different answer. . .By the way your link did not work.. . .YMMV. . .

Well, silica fallout still happens today and forms goo. Here's what happen when you take the coolant from a 2012 chrysler vehicle using a HOAT and mix it with 5% or more of the new OAT (AKA Grapejuice) that chrysler is using in a 2013 vehicle: http://starparts.chrysler.com/newsletters/newsletter_Oct_2012.pdf It's a PDF, so you need to have a PDF viewer to see this as with my last link. Seems to work fine for me anyways. On page 4 of the print, you can see the results of the mixing. This alone disproves that all coolants are compatible with one another.

Some coolants do have wide compatibility, but when you mix coolants, you are always diluting their additive package and I am not a chemist, so I can't tell you what would happen if you mix brand x with brand y. That's why I personally believe in following the manufacturer specs.

Also, Japanese auto makers tend to use a phosphated anti-freeze, primarily because of the intense use in aluminum and such, along with the quick development of that "film" that protects and coats all the parts quicker than a normal OAT. Then Daimler still uses a Silicated anti-freeze. Mix that Silicated with certain OAT anti-freeze and you can run into more of the gelling issues. Another reason why I'm really careful about anti-freeze selection.

However to the OP, I reviewed my coolant notes while at work today. If you did have a full flush in the system and have less than 5% of the old anti-freeze mixed with the new antifreeze and what they used is a universal coolant. You may be able to get away with it. However, you'd still want to flush fairly early compared to the normal 5yr/150k miles that I believe GM recommends for Coolant replacement.

Really the issue is mixing of coolants. However, even though people call it "Deathcool", I think it earned that name due to its early implementation and not understanding the full properties of OAT coolants, especially the 2-eha that's in DEXCOOL. That tends to soften certain seals and types of plastics overtime. Personally, I like that Chrysler's new OAT doesn't use 2-EHA so I'm hoping I don't have the issue with my motor in the future but I will still watch it.

If you're bored, here's a good article on Coolant in general, it goes through why certain packages are in certain coolants and such and may open your eyes to who uses what (and yes, this is a professional rag) (although it's titled to talk about Chrysler's coolant switch): SAE Coolant Article

[BenK]

Got the PM asking for details...

Here is a quote from my last response on the topic

OATs and HOATs has 'organic' material in there that is highly reactive to
oxygen and why most OEMs have removed the radiator cap. Moved it to the over
flow bottle, which is no longer an overflow, but pressurized. Along with a
translucent bottle body so you can check fluid level without opening to allow
O2 into the system

There is also an 'A' in the anagram, which stands for 'ACID', which etches the
metal surfaces to allow the 'O' to plate. That takes over 1,000 miles, while
the old silica based only too a couple hundred miles to plate

BenK wrote:
Here is my DIY kit to reverse flush and get nearly all of the old coolant out

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24272597/gotomsg/24272676.cfm#24272676


Back on DeathCool...some of the OATs and HOATs employ 2-Ethylhexanoic acid as
the organic acid to prepare (etch) metal surfaces inside the cooling system for plating
a corrosion protective coating

That acid is also a plasticizer...meaning it melts or softens plastic. If there
is any plastic in any of the coolant system gaskets (this included the head
gasket)...it will soften it to then potentially have it leak...

So the question...is all of the 2-Ethylhexanoic acid consumed during
the etching process that turns it into a metal oxide or is there any
left floating around looking for something to etch? The what about
the metal oxide floating around in the cooling system? Will it stay
as is?

Nope...if O2 gets in there...they will then combine and or react with that O2

[BenK]

Do a search using 'deathcool' here and on the internet

Turtle is correct

[LarryJM]

jbres wrote:
Have a question regarding changing coolant on my truck.
(truck is a 2007 gmc sierra 2500HD classic 2wd w. 6.0 gas job)
I had a gift card to Tire Discounters so took my truck there today to get a coolant flush/change. I told them I wanted it changed with something "dex-cool" approved as it states in my owners manual. Guy behind the counter says we use "Valvoline Max Life" which is a universal green antifreeze that mixes with any color and can use on any car or light truck.
Antifreeze I had in my truck was red and still in there from factory with 68,000 miles.

My question is was I wrong with letting them use the "Valvoline Max Life" as a substitute? It technically I guess isn't "dex cool approved" but also is universal, so is confusing me. I am trying to debate whether or not I need to get out the coolant they put in, and make sure to get back in the dex cool. Guy behind the counter actually said he would never use dex cool in any of his vehicles.
Any opinions or suggestions, I am trying to do some preventative maintenance and avoid head gasket failure years from now.
Thanks!

Personally, I think you know have a mess and IMO your biggest mistake was taking it to a place like Tire Discounters to have this type of work performed. All this thinking your might safe a couple of bucks since you had a discount card/coupon. These "quickie" places IMO only do it "their way" and which almost always is not the "best" or even "proper" way.

I'm not going to try like some others to claim 100 years of changing 1,000,000 vehicles of coolant or some other unverifiable claims, but over the last 12+ years have read hundreds if not thousands of coolant discussions mainly over on the DieselStop web site and will make the following comments for your consideration based on what I have learned or "gleaned" from those .... they are:

1. Personally I would not use DexCool in a vehicle not because it's an especially bad coolant, but it has it's "quirks" and is more susceptable to things effectiving it like the air and contamination issues already mentioned. However, it obviously works or GM would not be using it for many years, but they are the only major manufacturer using this type of coolant.

2. The two single biggest mistakes made in coolant maintenance is not doing a proper flush with "DISTILLED" water and if you are chaning types of coolant not again doing a proper flush to start with to get every trace of the prior coolant out.

3. The coolants of today are not those found just 5 years ago and most extended coolants now days are "low silicate" or "silicate free" and the previous issue of silicate drop out is now close to non existant.

4. I would never add things that I would call special additives such as rust inhibitors except for those recommended by either the car manufacturer or the coolant manufacturer. These "approved" additives are thing such as the "booster" for extended life coolants like the CAT and nitrite boosters for coolants such as the G-05 coolants used mainly in Ford/Chrysler/Mercedes vehicles.

5. Special "cleaning" type additives are IMO unnecessary and I would never have my vehicle serviced by a place that uses a machine like the B&M one that advocates their line of "cooling system cleaners". While almost all coolants say they can be mixed with others that might be true, but what they don't say is that you IMO loose all the benefits especially the longer life so while your engine won't blow up or die immediately you have wasted $$$ and have basically gained nothing and will in generally be back on around a 3yr or 36K change interval. This reduces life is also in play if you don't use distilled water only as the water part in your coolant mixture.

6. Now days there are basically 4 what I call types of coolant. One is those that are a mix of PG and EG "special" coolants that are water free like EVANS. Another is the typical straight EG what we often call the "green" coolant like prestone. The third are the OAT coolants which are mainly ones like the CAT, Mobil DELVAC, Shell Long Life, etc. which generally have the words "extended life coolant" (ELC) in them and DEXCOOL is a subcategory of these OAT type coolants. The final type is HOAT or Hybrid Organic Acid Technology coolant with the best know as Zerex G-05, Motorcraft "Gold", or the Mopar/Mercedes brand. There are also some minor classes used in some foreign cars like the Valvoline Asian Import and some others I don't even remember. Now days most big rig diesels use the OAT ELC type coolants. The HOATs are used by both Ford and Chrysler/MB in both their gas and diesel engines. To my knowledge only GM uses the special subclass of OATs know as DexCool and I'm not sure if it's used in both their gas or diesel engines or a subset of those.


7. Servicing your coolant doesn't require special procedures like back flushing or "power flushing", only some attention to detail and use of proper materials. Now below I will list my recommendations for two scenarios, one where you are changing the type of coolant such as I have listed above and in fact I would use that procedure if I was even changing brands within a type since the additional cost is zero and only time is involved. The second is simply replacing the coolant with the exact same type because you have met the stated service interval for that coolant. A word on this "service" interval. Almost all vehicle manufacturers have a longer "first service" interval with shorter subsequent intervals mainly because they do not account for a proper flush or ensuring that when you add you new coolant you are mixing that with "ONLY" pure distilled water. With both my procedures below IMO you can easily establish what I will call a new hybrid "service interval" between the factory fill number and the lower service interval listed in most vehicle maintenance schedules. For example for a factory fill state interval of 5Yr or 150K miles with a 3yr or 50K subsequent interval you can easily IMO go to around 4Yr and 100K miles. Now obviously if you go with these "extreme" or life long coolants such as the CAT ELC and a couple of others that require just adding boosters then I would just follow whatever they recommend for that specific coolant. Personally I'm a big fan of the HOAT Zerex G-05 coolant since it has a decent change interval and I just like to get new stuff in there every few years. Now on to the two scenarios I mentioned.

CHANGING FROM ONE TYPE OR BRAND TO ANOTHER TYPE OR BRAND OF COOLANT
Here the most important thing is to get every trace or better than 99.5% of what is now in the vehicle out. This scenario has the same objective as the second one below and that is to get you to a place where when you add your new coolant you are only mixing it with 100% or that 99.5% number of "PURE DISTILLED WATER". However since you have a different type of coolant I recommend flushing your system first using normal TAP water. You can do this by the old drain the radiator and fill scenario with getting the engine up to temp with the heater running between the drain and fills. I would recommend doing this procedure about 4 to 6 times and if your are not doing this during freezing weather there is nothing wrong in leaving that mostly water in there for maybe a day or two so your normal commute gets things well mixed up and the engine up to temp. Now don't leave it in there for 500 miles, etc. so some common sense is needed. Now move on to the second scenario.

CHANGING THE SAME BRAND AND TYPE OF COOLANT OR ADDING NEW COOLANT TO A SYSTEM THAT HAS BEEN FLUSHED WITH NORMAL TAP WATER.
Here this is very similar to the first, but now you will only be using distilled water for your drain and fills. Based on past experiences and calculations to get close to 100% distilled water you will need about 1.25 times the stated cooling capacity of your vehicle including the heater in distilled water and you simply do the old fill and drain until all but enough distilled water is left that you get from a normal drain of the radiator. A normal drain should remove just over 1/2 of the coolant in an engine so after your multiple drain and fills at your last drain you should have just under 1/2 of the capacity of the coolant system is PURE DISTILLED WATER. You then add enough 100% strength coolant to get you to that 50-50 to 60-40 coolant to water ratio and then top off your system with the distilled water that your saved. You will have a little distilled water and probably some coolant leftover at this last step and then just mix those to get say a 60-40 mix to use for topping off if needed. Remember this open mix has a shelf life and I would not use it past your next coolant change, but discard any saved at that time that is more than about a year old.

I know this is a very long winded post, but there I feel are some important points here and if one does decide to have someone else do the work the concepts of "NO CLEANERS", "GETTING ALL THE OLD COOLANT OUT", and having only "100% DISTILLED WATER" in your cooling system when adding new coolant for a coolant change are a MUST IMO for that shop to accomplish and hopefully you have some insight on what you should be asking to ensure these basic goals are met.

Finally, if in doubt come back and ask or research carefully before taking action or you will find yourself re doing what was done at a greater expense and with wasted time/effort.

Larry

[_1Flyboy]

. . .Jbres. . .-34 is a 50/50 mix. . .If it were ME, I'd purchase a can of antirust & add it to the system & maybe next year see if you are able to find a REPUTABLE Radiator shop capable of reverse flushing your system & adding the kind of antifreeze YOU feel comfortable with. . .At that time you might also want to consider inspecting the cooling system parts for possible replacement depending on age & milage. . .I'd suggest the long life antifreeze & again a can of anti rust to "sweeten" your cooling system. . .

[_1Flyboy]

. . .Silica fallout is usually found in OLD antifreeze( REALLY OLD!!! ) & usually in Diesel engines IF not keeping up with their nitrate levels/ coolant filters. . . NOT an issue with todays coolants as they are formulated (When is last time in last 10 years anyone saw silicate fallout?). . .I worked a successful automotive cooling system shop (33 years) & yes, actually purchased FULL trailer loads (20 pallets) of coolant at a time. . .Only took a few classes on coolants & such but had 43 years in cooling systems industry addressing & solving problems with cooling systems. . .Also talked to several AC Delco guys(at trade shows) about their Dex-Cool problems & every one of them had a different answer. . .By the way your link did not work.. . .YMMV. . .

[jbres]

I did test it and its good to -34 but I am even more dis-satisfied that I got a slight bit of red left in my overfill tank and the rest of its greenish yellow. I am just in the bind whether to hope its fine, or bite the bullet and put back in some dex cool

[jus2shy]

#1Flyboy wrote:
. . .My questions would be how much was drained out and/or was it truly "flushed" out; how much 100% antifreeze went back in to bring the % solution up to where it should be & did anyone think of also adding a can of anti-rust? (I'd recommend you check your % solution of antifreeze with a refractometer ) All antifreezes are compatible (yes you can mix red, yellow, green & orange & no harm is done; the claim being you get the least amount of corrosion protection of the lowest protection antifreeze)( If you doubt my words PLEASE provide expert published opinion )Dex-Cool has been especially hard on 4 & 6 cyl GM engines but appears to do OK in 8 cyl gas & diesel motors. . .Me, on my 6.6 diesel, & believing Dex-Cool was GREAT for business but not for my vehicles, I high pressure reverse flushed out the Dex-Cool at 52K miles & put in 70% solution of 5 year / 150K mile long life ( Off brand but made by Prestone ) added a can of anti-rust & a bottle of diesel additive.. . Did it again at 100K. . But changed both T-Stats this time. . .Just my humble opinion; please no yelling or rants - don't want to spill my drink. . .Also did all my friends GM vehicles (all have trucks) at 50K miles Everybody is happy. . .

Although color has nothing to do with anti-freeze type or performance, they are not all compatible. I've taken some anti-freeze classes from Staveley to learn the differences between OAT and older typical Ethylene glycol coolants. The type of film and way the film is formed that protects the metals that interact with the coolant are different and you can have serious issues, one of the most serious being Silica fallout. There's a reason why even Valvoline puts this little disclaims in their FAQ section on their antifreeze website:

"Can you mix Dexcool® with other antifreeze products? Link
Improper mixing of coolants has the potential to cause corrosion issues. Valvoline recommends using the correct antifreeze/coolant for your particular application."

[_1Flyboy]

. . .My questions would be how much was drained out and/or was it truly "flushed" out; how much 100% antifreeze went back in to bring the % solution up to where it should be & did anyone think of also adding a can of anti-rust? (I'd recommend you check your % solution of antifreeze with a refractometer ) All antifreezes are compatible (yes you can mix red, yellow, green & orange & no harm is done; the claim being you get the least amount of corrosion protection of the lowest protection antifreeze)( If you doubt my words PLEASE provide expert published opinion )Dex-Cool has been especially hard on 4 & 6 cyl GM engines but appears to do OK in 8 cyl gas & diesel motors. . .Me, on my 6.6 diesel, & believing Dex-Cool was GREAT for business but not for my vehicles, I high pressure reverse flushed out the Dex-Cool at 52K miles & put in 70% solution of 5 year / 150K mile long life ( Off brand but made by Prestone ) added a can of anti-rust & a bottle of diesel additive.. . Did it again at 100K. . But changed both T-Stats this time. . .Just my humble opinion; please no yelling or rants - don't want to spill my drink. . .Also did all my friends GM vehicles (all have trucks) at 50K miles Everybody is happy. . .