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Discussion Starter · #1 ·
What is so special about G12 coolant additive?

My coolant level is virtually on the minimum mark after 6,500 miles and six months.

I note the manual says
Owner's Manual said:
Topping up the coolant
...Do not use a different type of additive if anti-freeze additive G12+, G12 or G11 is not available. In this case use only water and bring the coolant concentration back up to the correct level as soon as possible by putting in the specified additive....
Unfortunately the coolant I have available on the shelf is blue "methanol free Mono Ethylene Glycol Anti-Freeze with a corrosion inhibitor system giving full protection against corrosion of materials used in cooling systems including aluminium"

So, looks like I'll be adding water but what's so special about G12.

Also, does anyone know the total coolant volume please?
 

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Mack The Knife said:
What is so special about G12 coolant additive?

My coolant level is virtually on the minimum mark after 6,500 miles and six months.

I note the manual says
Owner's Manual said:
Topping up the coolant
...Do not use a different type of additive if anti-freeze additive G12+, G12 or G11 is not available. In this case use only water and bring the coolant concentration back up to the correct level as soon as possible by putting in the specified additive....
Unfortunately the coolant I have available on the shelf is blue "methanol free Mono Ethylene Glycol Anti-Freeze with a corrosion inhibitor system giving full protection against corrosion of materials used in cooling systems including aluminium"

So, looks like I'll be adding water but what's so special about G12.

Also, does anyone know the total coolant volume please?
Tap water or distilled water? It used to be important didn't it? Not to use tap water that is.
 

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This is a cut/paste from a Bentley manual. Not sure if its any help.

Audi > TT > 2008
Maintenance
Description of work
Cooling system: Check freeze protection, add coolant, if necessary

Note:

All new engines are filled with coolant additive G 12 Plus according to TL VW 774 F (purple color). G 12 Plus can be mixed with the previous coolant additives G 11 and G 12 (red). Ensure that the system is replenished only with G12 Plus (due to its positive properties).

G 12 Plus is suitable as a filled-for-life filling for cast iron and all-aluminum engines and gives optimum protection against freezing, corrosion damage, scaling and over-heating.

G 12 Plus increases the boiling point to 275 F (135 C) and ensures for a better heat dissipation.

The additional coolant portion of the mixture must amount to at least 40% (freeze protection to -13 F [-25 C]) and should not exceed 60% (freeze protection to -40 F [-40 C]). Otherwise the freeze protection will be reduced and the cooling efficiency will be worsened.

The freeze protection must be ensured to approximately -13 F (-25 C).

Checking freeze protection and adding coolant additive if necessary

Special tools, testers and auxiliary items required

Refractometer T10007

Note:

Read the bright/dark boundary to obtain an accurate reading for the following tests. Place a drop of water on the glass to improve the readability of the bright/dark boundary. The bright/dark boundary can be clearly recognized on the "WATERLINE" .

Check the concentration of the coolant additive using refractometer T10007 (operating instructions).

The scale - 1 - of the refractometer is designed for coolant additives G 12; G12 Plus and G11.

Scale - 2 - refers only to coolant additive G 13. (previously L80)

Note:

The freeze protection must be ensured to approximately -13 F [-25 C].

If for climatic reasons greater freeze protection is required, the amount of G 12 Plus can be increased, but only up to 60% (freeze protection to about -40 F [-40 C]), otherwise freeze protection and cooling effectiveness will be reduced.

If freeze protection is insufficient, drain off required quantity shown in freeze protection table and add coolant additive G 12 Plus.

Note:

Observe waste disposal regulations!

Freeze protection to C Difference amount in liters
Actual value Specified value 4-cylinder engines 6-cylinder engines
0 -25 3.5 5.0
-35 4.0 6.0
-5 -25 3.0 4.5
-35 3.5 5.5
-10 -25 2.0 3.5
-35 3.0 4.5
-15 -25 1.5 2.5
-35 2.0 3.5
-20 -25 1.0 1.5
-35 1.5 2.5
-25 -35 1.0 1.5
-30 -35 0.5 1.0
-35 -40 0.5 0.5

Check coolant additive concentration after test drive again.

Checking coolant level and adding coolant if necessary

Check coolant level in expansion tank with engine cold.

Delivery inspection: Coolant level above the "MIN marking" - arrow - .

Inspection service: Coolant level above the "MIN marking" - arrow - .

If coolant is too low, add required amount according to mixture ratio.

Note:

Determine cause of fluid loss which cannot be attributed to normal use and rectify (repair measure).

Mixture ratio:

Freeze protection to Coolant additive G 12 Plus / TL VW 774 F Water
-25 C approx. 40% approx. 60 %
-35 C approx. 50 % approx. 50 %
-40 F approx. 60 % approx. 40%

Note:

Coolant additive G 12 Plus conforming to TL VW 774 F prevents freeze and corrosion damage, scaling, and raises the boiling point. For these reasons, the cooling system must be filled with radiator freeze and corrosion protection fluid all year round.

Especially in countries with tropical climates or when vehicle is driven under heavy load, the coolant improves the engine reliability by its increased boiling point.

The coolant concentration must not be reduced by adding water, even during the warmer season. The coolant additive ratio must be at least 40%.
 

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Discussion Starter · #4 ·
sane eric said:
Tap water or distilled water? It used to be important didn't it? Not to use tap water that is.
Blimey Eric, thanks for offering solutions instead of raising a further query :? :D

Is this because I recently reminded everyone you had the storage pack?

P.S. Now you've masked your TTC from the waist down the roof really does look Mauritius Blue (and yes, I know what colour you've told us you think it is :wink:).
 

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Discussion Starter · #5 ·
Er, Wow Vic - thanks for that.

VicTT said:
All new engines are filled with coolant additive G 12 Plus according to TL VW 774 F (purple color). G 12 Plus can be mixed with the previous coolant additives G 11 and G 12 (red). Ensure that the system is replenished only with G12 Plus (due to its positive properties).
So what's so special about G12 and its "positive properties"?

Is its boiling point so much better than other coolants?

Does topping-up with a different coolant really cause a problem?

VicTT said:
The coolant concentration must not be reduced by adding water, even during the warmer season. The coolant additive ratio must be at least 40%.
Not quite what the manual says but the gist is the same.
 

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I fairly sure that topping up with anti freeze other than G12 Plus or the ones declared as compatible produces BAD results - coolant goes brown/sludge-like or something along those lines.

As far as topping up with water is concerned that is most definitely the safest way to go if you don't have the right stuff. Shouldn't be a problem as from new the anti freeze concentration is way more than necessary to cope with our 'normal' winter temperatures
 

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The manual says that for filling the cooling system you use a filler unit and fill it with approx 8 litre of mixed anti freeze.

Once you've done the fill bit final level is done by running the engine etc.

Filling

Note:

The cooling system is filled all year round with a mixture of frost and corrosion protection additives and water.

Only coolant additive G12+ can be used, in compliance with TL VW 774 F . Other coolant additives may above all reduce the corrosion protection effect significantly. The damage resulting from this may lead to loss of coolant and consequently to severe engine damage.

Coolant additive G12+ can be combined with additives G11 and G12.

G12+ and coolant additives with the designation "conforming to TL VW 774 F" reduce frost and corrosion damage as well as lime deposits. They also raise the boiling point. For this reason the system must be filled all year round with frost and corrosion protection additives.

Because of its high boiling point, the coolant improves engine reliability under heavy loads, particularly in countries with tropical climates.

Protection against frost must be assured to about -25 ° C (in arctic climatic countries to about -35 ° C).

The coolant concentration must not be reduced by adding water even in warmer seasons and in warmer countries. The coolant additive portion must be at least 40%.

If for climatic reasons a greater frost protection is required, the amount of G12+ can be increased, but only up to 60% (frost protection to about -40 ° C), as otherwise frost protection is reduced again and cooling effectiveness is also reduced.

Only clean drinking water may be used for mixing coolant.

If the radiator, heater core, cylinder head and cylinder head gasket or cylinder block is replaced, completely replace the engine coolant.

Dirty coolant must not be re-used.

For coolant additive G12+, use refractometer T10007 to test frost protection in cooling system.

Push lower coolant hose onto radiator - arrow - .

Fill coolant reservoir of cooling system filler unit VAS 6096 with at least 8 liters of pre-mixed coolant with correct mixture ratio:

G12+ (40%) and water (60%) for frost protection to -25 ° C

G12+ (50%) and water (50%) for frost protection to -35 ° C

G12+ (60%) and water (40%) for frost protection to -40 ° C

Install adapter V.A.G 1274/8 on expansion tank.

Assemble cooling system charge unit VAS 6096 on adapter V.A.G 1274/8 .

Place air outlet hose - 1 - into a small container - 2 - . (A small amount of coolant is drawn off which should be reserved with the discharged air.)

Close both valves - A - and - B - (lever perpendicular to direction of flow).

Connect hose - 3 - to pressurized air.

Pressure: 6 to 10 bar pressure

Open valve - B - (lever in direction of flow).

A vacuum is created in the cooling system by suction jet pump.

Needle on instrument display must travel into green region.

Briefly open valve - A - (lever in direction of flow), so that the hose of the cooling system filler unit VAS 6096 is filled with coolant.

Close valve - A - again.

Let valve - B - remain open another 2 minutes.

A further vacuum is created in the cooling system by the suction jet pump.

Needle on instrument display must still remain in green region.

Close valve - B - .

Needle in display instrument must remain in green region, then sufficient vacuum in cooling system is obtained for upcoming filling.

If needle stands below green region, repeat procedure

If vacuum decreases, cooling system is leaking

Disconnect pressurized air hose.

Open valve - A - .

The vacuum in cooling system causes coolant to be extracted from cooling system filler unit VAS 6096 ; cooling system is filled.

Check coolant level and add coolant up to max. marking.

Start engine, allow it to run at approx. 1500 RPM for a max. of 2 minutes and fill coolant up to overflow hole of expansion tank.

Close expansion tank.

Allow engine to run until fan turns on.

CAUTION!
Cover cap of expansion tank with rag and open carefully, as hot steam or hot coolant may escape when opening.

Check coolant level and top off if necessary. With engine at operating temperature, coolant level must be at max. marking, with engine cold, it must be between min. and max. marking.

Shut off engine.
 

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Mack The Knife said:
sane eric said:
Tap water or distilled water? It used to be important didn't it? Not to use tap water that is.
Blimey Eric, thanks for offering solutions instead of raising a further query :? :D
NP, it is one of the few car facts(!) I know.

Mack The Knife said:
Is this because I recently reminded everyone you had the storage pack?
LMAO

Mack The Knife said:
P.S. Now you've masked your TTC from the waist down the roof really does look Mauritius Blue (and yes, I know what colour you've told us you think it is :wink:).
LMAO, I think you mean Deep Sea Blue, no? Anyway, nice one.

Your query was on a lot VAG related forums, as VIC said, all info said do not mix.

Nice post VIC.
 

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hitchbloke said:
Can you buy this G12 from anywhere other than Audi....Halfords perhaps?
G12+ is available from any Audi, VW, Seat or Skoda dealer and a 1.5 litre bottle will cost you £6.40 inc vat
 

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Thanks Paul

I did visit Audi Coventry earlier today, the parts dept was closed. :x

Why on earth would they not open when that's when most people would actually want to purchase items?
 

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DO NOT USE BLUE COOLANT WITH PINK! It will turn to jelly!

Get G12 from Audi dealer and dilute with distilled water.

Also read manual "when engine is warm coolant should be near max, when it is cold it may be just above min...."
 

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Discussion Starter · #15 ·
OK, now I'm confused all over again. :oops:

I have a 2008 model year TT TFSI and the manual says I have G12+ (TL-VW 774F) coolant. [smiley=book2.gif]
But the coolant in the reservoir is pink so I always assumed it was G12? If so, the Owner's Manual is wrong! If not, the Owner is wrong?!
Plus I've also seen elsewhere that G12+ was TL-VW 774G.

Anyway I now have a 1li bottle of coolant from Halfrauds (£7) which they say is correct. There is no mention of a 'G' type on the label anywhere but it does say "meets the requirements of Audi (TL774D)". It's in a sealed purple container so I can't see the colour of the contents.

Which Gxx is TL774D and is it appropriate here?

On reflection I think
G11 = TL 774-C
G12 = TL 774-D
G12+ = TL 774-F (thank-you Vic)

But I would appreciate a better informed opinion please. [smiley=help.gif]
 

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are you looking at the level when the engine is hot or cold.

Try looking when cold and take the cap off ? does the level alter?
 

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Discussion Starter · #17 ·
DXN said:
are you looking at the level when the engine is hot or cold.

Try looking when cold and take the cap off ? does the level alter?
Thanks DXN,

When the engine is warm the coolant level should be near max (or even possibly above), when it is cold it should be (just) above min.

I need more coolant!

My problem is understanding which TL774x code matches which Gxx code.

Anyone know? ...
 

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My coolant was also on the minimum level after 1000 or so miles. I contacted my audi dealer I bought the car from and told him that after spending £28k on a car I would expect a free bottle of G12 which the after sales manager aptly agreed to.
 

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Discussion Starter · #19 ·
The Rainman said:
My coolant was also on the minimum level after 1000 or so miles. I contacted my audi dealer I bought the car from and told him that after spending £28k on a car I would expect a free bottle of G12 which the after sales manager aptly agreed to.
Rainman,

Good call at only 1,000 miles.

Mines a lot higher! so I'm happy to buy the stuff - but I'm still so unsure about which TL774x code matches which Gxx code.
 
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