# g12/g12plus best coolant/what oil additive



## 1999.5GTIVR6 (Jun 15, 2011)

Albright so I just bought a full set of samco Silicon coolant hoses and am replacing them in the near future, but not sure what coolant I want to use. I know G12 is recommend But does anyone know about G12 plus? Or any other “better” coolant? 
also what oil additive should i ad if i want to clean it out (high kw stock turbo that i dont wanna blow)


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## Apexxx (Nov 10, 2011)

Don't use an oil additive, ever. Just go with 5w-40 and keep an eye on oil temps. 

Mobil 1 *High Miles* 10w-40 is the most stout oil around, more than you will ever need. The lighter viscs are good for winter. 

Coolant is coolant is coolant. The only incompatible coolants are HD (Olde silicated Prestone, and G-11) 

Dexcool and G-12 are identical, just use generic Dexcool "compatible" from WalMart, premixed is very easy to use. A step up is PEAK Global (GLOBAL!) another step up is G-05, which most mfgs use. It's lightly silicated, a Hybrid Organic Acid Coolant. Dex and G-12 are "OAT" coolants. 

Don't sweat it. Treat yourself to a new thermostat with the money saved, a "premium" one. I use ST Dexcool-compatible without flinching.


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## NJ1.8T (Nov 4, 2005)

No don't use anything from Walmart like dexcool or peak. Get the G12 which you can get at any Napa Store or order it online from the many different places you can get it. Its the best coolant for German Cars and the Engines. If your going to do a fluch, do at least 3 cycles of water through it before putting in new coolant. Also you can use something like Liqui-Moly Coolant Flush.
You can get everything you need from right here, there may be cheaper places to get it but this is where I always get my oils and coolant.

http://www.germanautoparts.com/Chemicals/Coolants?


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## Apexxx (Nov 10, 2011)

BZZT!


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## Anony00GT (Mar 6, 2002)

That may be what it says on the bottle, but G12 and DexCool are definitely NOT the same stuff. VAG has NEVER to my knowledge said that DexCool is approved.

Have you ever seen new G12 vs new DexCool? The color is totally different. Plus, DexCool causes all kinds of problems (sludge, rust, etc) in GM cars as they age, the stuff sucks. I wouldn't put it in anything, including a GM. When I service a GM and have to open up the cooling system, I usually flush it out entirely and refill with universal.

That being said, any type of premix "universal" coolant will work. It will mix with G12, DexCool, and old-fashioned green just the same. And yes it works as advertised, G12 is not required. Universal coolant will in no way damage or harm anything.


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## Apexxx (Nov 10, 2011)

Umm, no. 

Do you always spout opinions w/o any technical background? Please stop, you may be causing harm to other people's cars.


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## Apexxx (Nov 10, 2011)

Here's a start: Explain GM Dexcool sludge in GM, since you mentioned it.

Also, you might want to take a look at the ingredients, to make a fair comparison. :facepalm:

GM still uses Dexcool, and VW doesn't try to sell coolant marked "Dexcool".


Here, Ill make it easy for the other readers, since they are unlikely to get a factual answer otherwise. 

Seriously people, when someone says "I wouldn't use____" and cite nothing more than an owner's manual, that just means they don't have enough confidence in their own knowledge to draw logical conclusions about what's what.

http://www.motor.com/article.asp?article_ID=816

"GM and VW/Audi vehicles- For these applications, use DexCool because that's in accordance with factory coolant formula recommendations."

"Top up with DexCool in GM and VW/Audi vehicles, if you get one with the original coolant or DexCool." 





Don't be surprised when people claiming a baseline knowledge gleaned from the owner's manual cannot accept the facts, even when presented to them.


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## gmikel (Nov 10, 2010)

*what, no graph?*



Apexxx said:


> Here's a start: Explain GM Dexcool sludge in GM, since you mentioned it.
> 
> Also, you might want to take a look at the ingredients, to make a fair comparison. :facepalm:
> 
> ...


in your opinion nobody else is entittled to an opinion. i know you think you're smarter than vag, bmw mb and porche. sorta doubt it though. but then again they haven't been banned under half a dozen user names on this as well as other sites.


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## Apexxx (Nov 10, 2011)

Apexxx said:


> Don't be surprised when people claiming a baseline knowledge gleaned from the owner's manual cannot accept the facts, even when presented to them.




Like I said, more blind faith in spurious printed material = less faith in one's own understanding.

People coming to a technical forum with questions or problems deserve more than regurgitated owner's manual claptrap. Now they understand about coolants, and can research further if they wish, and make decisions based on facts, not conjecture.

Bottom line is the only "bad" coolants to mix in is olde Prestone and G-11.

Dexcool issues are the same as G-12, which include air leaks creating the sludge, so when a tech finds a sludged coolant system, they blame it on the owner's adding whatever random coolant, which may have actually been perfectly compatible. It's the air intrusion/leakage that causes the sludge.

Yeah, I think I know more about it than a grunge-level VW Tech. I know that MB believes in silicates in the coolant, so much that they have a sack of it in the expansion tank to replenish the system. Their coolant is lighty silicated, and organic acid technology, a hybrid, G-05. G-12/Dex have no silicates, necessitating the plastic waterpumps, etc. If you read the article, you'll know why.


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