Mopar 10yr/150K Coolant question

[Mantooth]

I returned the Dexcool coolant yesterday at the NAPA store. The lady at the counter, same lady who sold it to me, asked why I was returning it. Told her I had learned that Dexcool was not compatible and could potentially be harmful to my system. She looked at me like I had lobsters hanging off my ears. I just shrugged it off and finished the return. No use in getting into a p%#s@+g match.

Drove out to my dealer and asked for a jug. One jug of concentrate Mopar coolant set me back over $30. I also ordered an anchor clip for the cargo area of my Durango - passenger side one popped out and disappeared. That was also over $30, for a plastic anchor. Total bill of $60 + dollar for two simple items. They got me!

 

[The_Nuke]

Originally Posted By: Panzerman
Every Ford I have owned has had a warning on the coolant tank don't add Green to orange or vice versa. If the Mopar antifreezes were so toxic, I am thinking there would be a sticker.
Most sites are saying OAT and HOAT are basically the same.
One has hybrid organics and the other natural.
I topped off my 2016 with the Mopar Orange and it's purple. Now we are talking less than a pint, but I see no issues and that's was 6 months ago.


I am far from an expert on the matter, but my last 2 vehicles have been pre-2012 Dodges, so I have had to do some research on the topic of which coolants to use for their engines as well as go through several coolant flush and fills between them. With that in mind, here's what I can say for sure: the HOAT stuff has a bad habit of leaving sludgy, chocolate pudding-like deposits in the cooling system if it is mistreated (e.g. by mixing non-xOAT coolants with it) or neglecting it for too long (e.g. pushing it beyond its 5 yr/100K mile service life). I have seen that behavior first hand, and it is not a pretty sight (especially if it is your own vehicle in which the carnage has occurred).

As far as topping off your cooling system's OAT mix with some HOAT coolant, I will say that goes against everything I have read about their compatibility - they are not supposed to be mixed according to all the available documentation. Now, does that mean that bad things will happen when they are mixed? Not necessarily, as you have seen in your case.


It is my own personal belief (not directly supported by any documentation or industry articles) that the directive to never mix HOAT and OAT is more about enforcing the distinct boundary between their respective operating environments and service lifetimes. The HOAT stuff had a specific service life and method of protection within the engine. The OAT stuff had a different, much longer service life spec, but it has a different method of internal parts protection while in service. And because of the difference in those aspects of the coolants' behavior, mixing them should theoretically be detrimental to the overall engine coolant's service life and internal protection efficacy. But I suspect the company figured instead of declaring "don't mix; bad things COULD happen.", they could get the point across more effectively by using some really stern language - "don't mix; or bad things WILL happen!"

As always, the truth probably lies somewhere in between. Mixing them COULD cause bad things to happen, but as you've seen, it doesn't necessarily mean bad thing WILL happen. On the other hand, I have seen bad things happen when mixing HOAT with other types of coolants (non-OAT), so there is certainly an incompatibility aspect with these xOAT coolants.

In your specific case of topping off the OAT with some HOAT, it is my opinion that, while not good for the overall coolant's lifespan and protection ability, you didn't do any real damage to the overall coolant's ability to protect because of the recipe you used to mix them (OAT was main ingredient; only a dash of HOAT was added). Now, had you been running a system full of HOAT and then topped off with some OAT, I believe you would have set yourself up for some pudding deposits if/when you pushed the coolant up to or beyond its service life (5 yrs/100K miles).

And heck, the same may hold for the OAT topped off with the HOAT, but you'll have to push it out to 10 yrs/150K miles first to verify that hypothesis...

And that, fellow BITOGers, is my story, and I will be sticking to it!

Nuke

 

[The_Nuke]

Originally Posted By: Mantooth
I returned the Dexcool coolant yesterday at the NAPA store. The lady at the counter, same lady who sold it to me, asked why I was returning it. Told her I had learned that Dexcool was not compatible and could potentially be harmful to my system. She looked at me like I had lobsters hanging off my ears. I just shrugged it off and finished the return. No use in getting into a p%#s@+g match.

Drove out to my dealer and asked for a jug. One jug of concentrate Mopar coolant set me back over $30. I also ordered an anchor clip for the cargo area of my Durango - passenger side one popped out and disappeared. That was also over $30, for a plastic anchor. Total bill of $60 + dollar for two simple items. They got me!


I find myself in similar situations more and more these days. On one hand, you expect that the folks manning the parts stores will have the knowledge you seek when you go there. But on the other hand, how realistic is it for any person working those lower level jobs to know everything about everything?

I will admit that I have been guilty in the past of (subconsciously) just expecting them to automatically know all the caveats and exceptions surrounding confusing subjects like which coolant for which year Dodge and then getting upset when I discover that they don't know anymore than I do on whatever subject...or worse, have the wrong answer in response to whatever question I am asking. It's a no-win situation for them IMHO. They can't possibly know everything about every model of car/truck. They can only hope to know most of the things about most of the cars/trucks and depend upon their computer systems to fill in the rest. Yet they are constantly put at a disadvantage by customers coming in who will know everything about their specific car/truck, not to mention being hamstrung by out-of-date, unusable, or just plain bad computer software systems put in place for them to use in their daily job.

As much as I like all things automotive, you couldn't pay me enough to do those counter jobs. I would not last a week before I either lost it and quit in a fit of rage, or my brain exploded from all the stupidity I had to constantly endure coming from the customers and their unruly children.

But I digest...

You got the right coolant (eventually), and ultimately no harm was done to your engine, so it was a good week for you. Say a prayer for the counter jockeys out there and keep on trucking. That's really all any of us can do in that scenario, isn't it?

 

[Panzerman]

I drained the HOAT out of my 2006 Dodge Ram a long time ago, flushed it and switched to Peak Global. The Challenger I will probably leave alone for 10 years since that coolant is better.
I seen the HOAT do it's orange slime before and the guy that had the one Ford before me had some issues with mixed Antifreeze because I had to flush the sludge out of that tank and radiator. It now has the G-5 in it. No further sludging issues.

 

[KrisZ]

G-05 is HOAT, Dexcool is OAT.

 

[69GTX]

What The_Nuke said earlier is my understanding after reading for hours on the subject earlier this year. The Auto Parts stores eagerly sell you the DexClones that will supposedly work with ANY system. Maybe they do and maybe they don't. But, 1 quart or less in a 12-14 qt system isn't likely to be a death sentence. I made the mistake of adding a gallon of Prestone DexClone (weak OAT?) this past summer not realizing "universal" coolants are probably anything but that. Ended up flushing the heck out of the system before shifting to G-05.

If I needed to add a quart or less I might be tempted to add just Demin/DI water to get by...as long as my concentration was still good for low winter temps and didn't fall below an approximate 40/60% concentration. At least that might get me to the time when a regular flush/fluid exchange was needed.

 

[440Magnum]

Originally Posted By: Panzerman

Most sites are saying OAT and HOAT are basically the same.
One has hybrid organics and the other natural.


That's just plain nonsense. Both sentences.

Inorganic antifreezes (the old kind) contain inorganic corrosion inhibitors (typically silicates and nitrites, among others).

OAT antifreezes contain only organic acid corrosion inhibitors, period.

HOAT is a hybrid of organic and inorganic inhibitor compounds. For example, G-05 uses organic acids, plus silicates and nitrites.

To compound matters, among OATs there are a number of different organic acids that can be used, DexCool being notorious for using 2-ethylhexanoic acid, which can soften some gasket materials. Its perfectly compatible with others, so it works well in engines designed from the ground up to use it. Mixing OATs can sometimes lead to problems, and mixing OAT with HOAT or inorganic based antifreezes is even more likely to cause problems, because the OATs are formulated expecting no inorganic inhibitors to be present. Incompatible acids can interact, and/or cause the inorganic components of HOAT or inorganic antifreezes to precipitate out of solution prematurely.