Cannot find service interval for Audi coolant

[John_Corey]

Hi mechanix,

It has been shown again and again that G11 and G12 are not compatible. G12 Plus is compatible with G12 and G11. It follows that not all G30 coolants are created equally. Any G12 or G12 Plus is a G30 coolant, but G30 coolant is not a G12 Plus coolant. Maybe that's why VW does not say "use G30," but why they specify G12 Plus if compatibility is required.

Since I am now speculating, although reasonably, I am deciding to let this topic go now. Anybody can inform himself by contacting the technical departments of VW, BASF, Zerex, etc.

Anybody is at liberty to do as he chooses. However, one should not give advice based on assumptions and hearsay.

I appreciate the civilized discourse!

Cheers,
-J

Originally Posted By: mechanicx
BASF classifies both G12 and G12+ as G30 OAT and not two separate ones, along with G34 Dexcool. Dexcool can be mixed with silicate containing coolants like american green, which is even a completely different formula, only the dyes clash.

 

[mechanicx]

Yes G12 is consider to be incompatible with G11 whether because of brown color or actual sludging. There is conflicting information from VW about G11 being even compatible G12+ and G12++. And whether the G11 part number is referring to green or blue G11 and whether this G11 formula was based off of G-05 or now G-48. G-05 based would not be compatible with the newer coolants. It's clear that G12, G12+ and G12++ are compatible with another. Although G12++ should be switched entirely IMO since it is a slicated formula.

Anyway, I was not suggesting anyone mix G12 with G11. I was only discussing the coolants in general. My suggestion as always is to do a complete change when switching coolant types, whether to dexcool/dexclone or to G12++. It's not entirely speculation on my part. I have a deeper understanding of coolants than just whatever the OEM recommends. Dexclone with a non clashing dye is being mixed in lots of coolants or to replace them, not that I recommend mixing non-identical formulas.

 

[mechanicx]

Originally Posted By: Garak

Personally, I'd never mix coolants unless I was sure they were the same (or close enough) i.e. GM Dex-Cool, Halvoline Dex-Cool, Zerex Dex-Cool. For mine, which now has a dexclone, the VW/Audi procedure for proper flushing was followed. I don't like mixing potentially incompatible coolants, but I can't see there being any problem with having a Dex-Cool in the Audi.


I don't see any problem with Dexcool in the Audi with a pressurized reservoir either. With G12 and G12+ you just replaced one OAT with another (Dexcool).

Quote:
When coolant manufacturers cannot agree between their bottles and their website, and others specify more than one meeting G30, I don't have a lot of confidence in what they're telling me. That may make some people more likely to spring extra dough for the OEM coolant. Not me; I'll do the opposite and find what works.


They like to tell you that you have to have this one and only brand and formula. The one that they sell. But OAT coolants have similar properties in reality.

Quote:
GM, for all its faults, has made the Dex-Cool spec fairly universal through its licensing process. Plenty of manufacturers make dexclones and licenced Dex-Cool. Ford is now going the Dex-Cool route, too.

I have a healthy, sealed cooling system, and am using a dexclone with confidence.


Granted an Audi/VW or whatever is not a GM vehicle, but the same principles required to make one OAT coolant work well apply to all others. GM doesn't require a specific formula, only that various standards are met. Whether the formula is 2EHA, sebacic and 2EHA, etc a coolant plastic gasket material that deteriorates with one OAT would deteriorate with the other. Corrosion and metal protection is not even in question. In reality only a finite types of plastics are best suited and used.

 

[Garak]

Originally Posted By: mechanicx
Granted an Audi/VW or whatever is not a GM vehicle, but the same principles required to make one OAT coolant work well apply to all others. GM doesn't require a specific formula, only that various standards are met. Whether the formula is 2EHA, sebacic and 2EHA, etc a coolant plastic gasket material that deteriorates with one OAT would deteriorate with the other. Corrosion and metal protection is not even in question. In reality only a finite types of plastics are best suited and used.


I just checked my copy of the Bentley Audi 100, 200: 1989-1991 Official Factory Repair Manual. It says G-11 was the factory fill. It does not require coolant to any particular specification. It simply requires that it be phosphate free. So, the dexclone stays.

 

[mechanicx]

See if they were calling the coolant G11 back in '89 then I'm thinking it was probably similar to G-05 but not nitrited. No wonder G12 shouldn't be mixed with it and neither should G12+ and ++. I probably would've went with G05. What's funny is I think they discontinued it and G11 became blue G48 which has 2EHA anyway and would be more G12+ compatible lol. Glysantin recommends G48 for these older vehicles.

 

[Garak]

Originally Posted By: mechanicx
See if they were calling the coolant G11 back in '89 then I'm thinking it was probably similar to G-05 but not nitrited. No wonder G12 shouldn't be mixed with it and neither should G12+ and ++. I probably would've went with G05. What's funny is I think they discontinued it and G11 became blue G48 which has 2EHA anyway and would be more G12+ compatible lol. Glysantin recommends G48 for these older vehicles.


I would agree. I had thought of going to G-05, but only premix is available (or concentrate at an obscene price). I have seen G11 available from American online sites (which probably wouldn't ship coolant over the border) at a reasonable price. It's all been backspeced anyhow.

In any case, I always do a complete flush, so compatibility between coolants isn't so much of an issue. G11 wasn't mixed with anything else, at least not on my watch.

 

[gamefoo21]

Originally Posted By: mechanicx
If Dexcool ate the plastics used how would the VW OAT coolants with sebacic (which is also used in Havoline Dexcool and also a "plasticizer") not? Sounds like old wives' tales not backed by testing or others experience with it.


Different chemicals of the same family will behave differently. Just because they are both OATs that chew on plastic, doesn't mean they'll attack the same plastics or even use the same inhibitors.

I have the 2 year old temp sensor that died with it's softened casing, it's kind of cool being able to peel plastic with your finger nail.

The shop 2 years ago poured in Deathcool to top off the system that was filled with green. Oh the sludge I flushed out of that system... *shudders* Anyhoots, no old wives tale, just first hand experience.

Out of all the readings, the chemical package of the G12 seems to just be a better overall unit than Dexcool.

 

[mechanicx]

I don't know about your cooling system and temperature sensor but I've seen SAE testing of various OATs and their effects on polymers, and the OATs had similar effects. Some types plastics are more OAT resistance than others. Plastic cooling parts in general are not the most durable regardless of coolant type. I still say if your cooling system can't hold up to 2EHA it can't hold to sebacic either. But if someone wants to run the original coolant I don't fault them either.