Swap VW G-12 for G-05? Getting a new rad and WP...

[Audi Junkie]

My BOSCH mechanic always sticks with factory fluids. He claims G-12 causes leaks, it "gets through seams". So, why should I let him use it during my timing belt/water pump/radiator service. I have used G-05 in a few cars, a Volvo, old Audi, a '95 Audi that needed a flush badly and now I want it for my 1998 A4 V6. My radiator was shot by 80k, not good by any standard. Should I use the G-05 now? I have read every post on the subject I could, here it goes. I know my mechanic will be mad.

 

[dagmando]

G12 is a VERY high quality coolant when used exclusively but must NEVER be mixed with G11 or other brands. If you are currently using G12, let him replace it with the same because G12 is specifically compatible with Audi/VW and was the replacement to their "orginal" lifetime coolant - G11 during the 96-97 MY

 

[Audi Junkie]

My 98 uses G-12 now and I want to switch to G-05. G-11 to G-12 swap is dicey but G-05 seems ideal for this car especially due to the fact I am getting a new rad and WP. I think G-12 was rushed to market to provide "Lifetime Service" without enough long-term testing. Shades of Dexcool, similar chemistry. Mercedes has a much longer track record with G-05, back to pre-1992 I believe. If someone has technical info on this, I'd be very interested. The suggested top-off for G-12 by Radiator Makers' Assoc is Dexcool, yikes.

[ September 14, 2004, 05:58 PM: Message edited by: Audi Junkie ]

 

[Mickey_M]

quote:

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Originally posted by Audi Junkie:
My BOSCH mechanic always sticks with factory fluids. He claims G-12 causes leaks, it "gets through seams". So, why should I let him use it during my timing belt/water pump/radiator service. I have used G-05 in a few cars, a Volvo, old Audi, a '95 Audi that needed a flush badly and now I want it for my 1998 A4 V6. My radiator was shot by 80k, not good by any standard. Should I use the G-05 now? I have read every post on the subject I could, here it goes. I know my mechanic will be mad.

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The current factory fill for VW/Audi is BASF Glysantin G 30. It is a nitrite-free,
amine-free, phosphate-free, silicate-free, borate-free OAT. G 30 is the VW/Audi spec, G 33 the Peugeot/Citroen version, and G 34 the Opel/GM Europe/Saab edition of the same basic DexCool type of coolant. G 12 is the VW code for G 30, and in the U.S. they apparently acquire it from Pentosin and Valvoline.

http://www.basf.de/en/produkte/chemikalien/spezial/glysantin/specification/?id=Sy8lX5aBabsf2kt

http://www.basf.de/en/produkte/chemikalien/spezial/glysantin/productrange/?id=Sy8lX5aBabsf2kt

G 05 is a Daimler-Chrysler spec which contains nitrite and some silicate, but is phosphate-free and is a HOAT. It is used in Mercedes, Chrysler, and Ford.

G 48 is the older VW/Audi factory coolant, also known as G 11 - the VW code. It is nitrite-free, amine-free, and phosphate-free but contains silicates.

If one “gets through seams”, they’ll all get through seams.

The advantage of G 05 over G 30/G 12 is that it is handles cavitation a little better, but the G 30 if properly maintained should last longer.

BASF’s recommended change interval is 3 years for G 05, 3 years for G 48, and 4 years for G 30.

 

[Audi Junkie]

Thanks, I am still going for it. The silicate doesn't bother me but what the heck does the nitrite do, good and bad?

 

[Mickey_M]

quote:

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Originally posted by Audi Junkie:
Thanks, I am still going for it. The silicate doesn't bother me but what the heck does the nitrite do, good and bad?

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For your car it should do nothing either way.

It's there so it can be used with wet sleeves, which makes G 05 usable in many trucks.

 

[ebaker]

I believe my 2001 Porsche uses Pentosin G12. The dealer sells it by the litre for an outrageous price. Is there a more economical way to obtain this coolant when it is time to change it? The capacity is over 6 gallons. Would a flush then refill with G05 be a good alternative?

 

[smith45]

ebaker, www.ecstuning.com sells Pentosin g12 for $9.55 per 1.5ltr.

 

[Audi Junkie]

Did not see anything at ECS. You could always substitute generic Dex-cool for $4.

 

[Mickey_M]

quote:

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Originally posted by ebaker:
I believe my 2001 Porsche uses Pentosin G12. The dealer sells it by the litre for an outrageous price. Is there a more economical way to obtain this coolant when it is time to change it?

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DexCool and G 12 are basically the same thing.

A complete drain and flush and refill with DexCool
would make getting top-offs a lot cheaper.

If you want the G 12, though, Valvoline does make it and sell it:

http://www.valvoline.com/pages/products/category.asp?cid=2

as G 30, complete with the factory red dye.

I have not seen it in retail distribution, so you may want to contact Valvoline to find out who carries it.

But there really is not a hair's difference between G 12, G 30, and DexCool.

 

[Audi Junkie]

Checking in with my mechanic, he still says G-12 works through seams like crazy. This parallels some Dex-cool stories. As I explained the similar chemistries of Dex and G-12, we connected all the bad Dex stories with the G-12. For all the car stuff he knows, the info about Dex and G-12 being "compatible" was news to him. He ok'ed the use of the G-05 in my newer Audi, but nixed it in older G-11 (blue) cars. Too bad, I did our 20 y/o Audi and out 1995 A6 already. Maybe he experienced the process of stuff being dislodged by conversion to the OATs which clogs and wears cooling parts. My solution is a 2nd flush of G-05 after a few months. I will not go back to the destructive silicate greens or Deathcool.

 

[moribundman]

My '96 A34 came with G11. After a few months I switched to G12 without any problems. The G12 sold at US dealers is made by Zerex, I believe. I see Pentosin G12 at very well-stocked local auto parts store for about $28 per gallon (dilution with H2O is normally 1:1).

I have no reason to believe that G12 tends to leak more than other coolant. After 8 years and over 130k miles, I've had no problems with G12 or the cooling system whatsoever. The current fill is 4 years old (last TB/WP change), and clean. No leaks.

How can G12 be the same as Dexcool? Wouldn't have Audi/VW/Porsche had problems similar to GM?

 

[Mickey_M]

quote:

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Originally posted by moribundman:
How can G12 be the same as Dexcool? Wouldn't have Audi/VW/Porsche had problems similar to GM?

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If you'll go to the BASF website url that I provided, you'll see three "Glysantin" chemistries: G 30, G 33, and G 34. All three are DexCool-type OATs, approved for VW/Audit, Peugoet/Citroen, and GM respectively.

I think you'll see that except for their colors, chemically they're all pretty much the same thing.

Valvoline (Zerex) and and the trade organization of independent radiator shops recommend DexCool as the replacement for the VW/Audi coolant.

The problems GM is having with DexCool appear to me to be the result of bad designs on GM's part of their V-6 engines and lack of maintenance on the part of owners, not a problem with the chemistry. That's why VW/Audi aren't having problems.

Any of the OAT coolants should work fine *if* they are not allowed to run low on coolant and *if* cavitation is not an issue in the design.

That's the Achilles' heel of these OAT coolants - they do a bad job of recovery from cavitation. Once the protective barrier is broken a chain reaction of rust and additional damage can take place pretty quickly.

I tried the DexCool in an older Honda when it first came out and ran it 150,000 miles with no problems at all.

If you're not going to keep your system topped off, however, G 05 looks like a safer bet.

 

[Audi Junkie]

My rad was blowing G-12 out both sides by 75k.

It was running low occasioinally but I topped when the warning light came on. I am bitter about the radiator and am looking for a better "solution". I want to keep the car for a long time. I plan to swap the G-05 again after 50k miles. Does cavatation take place at high RPM? If so, I redline several times a day.

 

[moribundman]

I'm almost 100% sure that G12 and G 05 are compatible. I can't cite my source, though. If you switch coolants, I would flush the cooling system in any case -- not with distilled water, but with tap water and until it comes out clean. For mixing new coolant I'd use distilled, demineralized, water.

By the way, I switched my car from G11 to G12 and have been using the latter for 9 years. The current fill is 4 years old and will be replaced later this year when the timing belt and water pump have to be replaced. The coolant looks still fresh without any visible contamination.

 

[ChrisW]

I dont mean to bring back an old thread, however, is switching from G 12 to G 05, would a complete flush with distilled water be necessary? Or are teh G 12 and G 05 similar enough that a drain and refill would suffice (provided I got most of the old G 12 out on the drain)?

I was giving it some thought recently about how the water pumps on 30v audis usually go out before the timing belt does, and was thinking about swtiching to G 05 wo see if that would help.