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Hammer Time
Hammer Time, L1 Master Technician
Category: Car
Satisfied Customers: 4942
Experience:  ASE Mastertech with Adv level Engine performance cert.
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2002 VW Passat: I put in the wrong type of coolant and it..flush

Customer Question

I have a 2002 VW Passat. Apparently, I put in the wrong type of coolant and it ruined the entire engine! Can't they flush the engine out or something? I can't believe that I need to buy an entire new engine!

Optional Information:
2002 Volkswagen Passat 1.8 liter

Already Tried:
Nothing, it is sitting in the shop.

Submitted: 10 years ago.
Category: Car
Expert:  Hammer Time replied 10 years ago.
You need to get more details of just what was damaged and why. That's not making any sense at all. I don't know of any coolant on the market that can do any damage to an engine on it's own.
Customer: replied 10 years ago.
Reply to Hammer Time's Post: They told me that it turned to gel inside the engine and contaminated everthing?
Expert:  Hammer Time replied 10 years ago.

Apparently one of their coolants is not compatable with some other types of coolants and has a reaction to the mix.

Coolant Type

G 12 Plus according to TL "VW 774 F" (purple)

Purple G12 Plus is compatible with the red G12 coolant additive. Engine coolant G12 Plus must not be mixed with other coolant anti-freeze. Mixing with other coolants can cause serious engine damage.

Models: All

New antifreeze, Part No: G 012 A8F A4: Color = Purple
Replaces Part No: ZVW 237 G12 (Pink)
Can be mixed with ZVW 237 G12 (Pink)
DO NOT mix with ZVW 237 105 (green) or any aftermarket antifreeze
DOES NOT replace Part No: ZVW 237 105 (green)

Antifreeze, Part No: ZVW 237 G12: Color = Pink
Can be mixed with G 012 A8F A4 (purple)
DO NOT mix with ZVW 237 105 (green) or any aftermarket antifreeze
DOES NOT replace Part No: ZVW 237 105 (green)

Regular antifreeze, Part No: ZVW 237 105: Color = Green
DOES NOT replace and cannot be mixed with Part No: G 012 A8F A4 (purple)
DOES NOT replace and cannot be mixed with Part No: ZVW 237 G12 (Pink)

Follow coolant mixing instructions Cooling system - Service and Repair - Procedures - Draining and Filling , for the Model you are working on.



  • Only use coolant additive G12 (according to TL VW 774 D). Characteristic: red color
  • Do not mix G12 with any other coolant additive!
  • If the fluid in expansion tank is brown, G12 has been mixed with other coolant. If this is the case, coolant must be replaced.
  • "G12" and coolant additives marked "In accordance with TL VW 774 D" prevent frost and corrosion damage, scaling and also raise the boiling point of the coolant. Therefore, cooling system must be filled year round with frost and corrosion protection additives.
  • A higher boiling point improves engine reliability under heavy load particularly in countries with tropical climates.
  • Frost protection additives protect against frost to about -25°C (about -35°C in arctic climates).
  • The coolant concentration must not be reduced by adding water even in warmer seasons and in warmer countries. The antifreeze ratio must be at least 40%.
  • If for climatic reasons greater frost protection required, the amount of G 12 can be increased, but only up to 60% (frost protection to about -40°C ), otherwise frost protection and cooling effectiveness will be reduced.
  • If the radiator, heater core, cylinder head or cylinder head gasket is replaced, completely replace the engine coolant.

I might sill get a second opinion on just how much damage has been done to the engine. If you know that you severely overheated the engine, then it may be possible to have that much damage but if you didn't, get another opinion on it. You'll need to at least flush out the coolant and refill with the correct fluid before attempting to drive it if it's still drivable.

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