My car has a slow coolant leak from the radiator so I've been topping up with distilled water until I can afford to have it fixed.

Colder weather is here, so I bought an antifreeze test to make sure the coolant isn't too diluted.

Test is showing protection down to -7c and I want it protected to -20c.

Can I turkey baster some of the current mix out of the expansion tank, pour in G13 concentrate, run the car for a while and then retest & repeat until it's where I want it? Any risks to doing this?

Car's a 2014 VW Golf GTi.

1 Answer 1


No risks whatsoever. You're getting your mixture right, which is what it needs.

Since your GTI has an expansion (recovery) tank, you'll notice there is a constant flow of coolant into it (upper small hose). This will help you with your endeavor. Instead of using a turkey baster, you can pull this hose off (when the engine is cold), then use it to dump the excess coolant out of the system. Once you get the amount of coolant out and you've reattached the hose, the design of the system is such the coolant constantly flows into the ball from this hose, it will mix the new antifreeze into the system fairly quickly. Mind you, there's nothing wrong with using a turkey baster, just thought I'd throw this in there for an alternative if you so desired.

Also remember, it doesn't have to be perfect. While a 50/50 mixture is recommended, going over that is not going to hurt anything either. For extreme environments, you can run up to a 70% mixture of antifreeze to water. If you're over the 50% mark, it's not going to hurt anything.

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    Just to emphasize your answer 70/30 Coolant/water is the max concentration. Higher concentrations will not cool the engine efficiently. I mention this as I have seen people try to run straight (non-prediluted) coolant because they thought it would be better. Commented Apr 24, 2023 at 14:18

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