I bought coolant this morning as my car was running on empty. I was told to pour the whole 1 liter bottle in and top with water. After pouring the bottle of coolant in there's no room for water. What should I do?

  • 2
    Welcome to the site. Can you tell us the year/make/model/engine of the car, as well as the type of coolant you are utilizing? Also, what was the exact amount you put in? Is it a "litte" (little?) bottle, or possibly a "liter/litre" bottle? Did you add this directly into the radiator or into the overflow reservoir? We really need a lot more information to adequately answer your question. More than likely you won't need to do anything because you can go to a 70/30 mix without causing problems. The bigger problem is, where has your coolant gone to which required you to refill? Aug 3, 2017 at 12:41
  • It's a,2005 Vw,TOURAN 1.6.It was a litre bottle of coolant and I added it into the reervouir (I think)!
    – user31382
    Aug 3, 2017 at 13:14
  • The other possibility was that you added it to the screenwash reservoir...
    – Solar Mike
    Aug 3, 2017 at 13:49
  • It was defiantly poured into the correct reservoir as ive sern itwith
    – user31382
    Aug 3, 2017 at 13:54
  • Most VW's I've dealt with have a closed system. Here in the States, most of them around 2005 (may even still be this way) had a "ball" which was the reservoir and had the vent cap on it. Let us know if this describes what your vehicle has. Aug 3, 2017 at 18:30

1 Answer 1


My 2.5 litre engine has 7.5 liters of coolant. If the original mix is 50/50, and it goes down to 6.5 liters (3.25 liters of coolant + 3.25 liters of water), and you add 1 liter of coolant, you now have 4.25 liters of coolant and 3.25 liters of water. It's 57% coolant and 43% water. Not an ideal mixture, but if you keep doing that (add just coolant without water), the mixture will become richer and richer in coolant.

So, my advice would be to fix the coolant leak whenever convenient (being low on coolant is always as sign of a leak), and when it is fixed, fill it with proper mixture. You can in the mean time continue running on the 57/43 mix. No damage done by using this mixture, unless being low on coolant did some damage to your car.

If you have to add coolant again due to the leak being active, next time will with 1 liter of water only and then fill with 50% water, 50% coolant after that.

Of course, if you have some of those trendy 1 liter turbocharged little engines, they may have less coolant capacity and therefore your mixture could perhaps be so much off that it would be a good idea to repair the leak ASAP and fill with proper mixture.

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