Let's say the capacity of the cooling system is 7 liters.

Lets say you have 1 liter in there. Besides the fact that if you have a leak or it evaporates you will have less time, is there anything wrong with driving around with 1 liter all the time provided you keep it topped up to that level? What is the purpose of putting more coolant in?

This question came to mine as I had a car with no coolant(dont ask me how) but there were no leaks. Afterwards I just put in 1 liter of coolant as the shop didn't have anymore and was wondering if it was too low to drive with and if it could have caused a problem.

  • @Pᴀᴜʟsᴛᴇʀ2 I'm not sure what you mean but 1 liter could be both the total and also be considered low at the same time? But the coolant capacity as per manual was 7 liters, and I drove around with 1. May 8, 2018 at 23:32
  • I frankly don't believe this story. How do you know it was completely empty to begin with? What shop only had one liter of coolant on hand? If you were actually as low as you say it would have overheated and seized within minutes.
    – agentp
    May 10, 2018 at 14:47

2 Answers 2


Yes it absolutely can cause you issues. Most modern cars have to have the coolant all the way filled and burped (any air in the system removed) or it will not function properly. Given an example of my 2003 Civic. It had a small head gasket leak where it would burn a small amount of coolant every time I drove it. If I did not keep up on the coolant (refilled it every time I drove the car), it would overheat. So even low coolant will cause problems.

If you only have one litre of coolant in a system which requires 7 liters to be full, you have an issue where the coolant level most likely doesn't even reach the level of the coolant pump, and therefore will not make the circuit through the engine to start too cool it. You will most likely start to overheat very quickly and will cause damage not much longer after that.

Even with only 1/2 the coolant in the system, you will most like be exactly the same as only having only a single liter. The coolant may reach the level of the coolant pump, but will only have coolant in spurts. There will be massive hot spots which will form inside the engine, which will again cause overheating and damage if driven on too long.

Any which way, having the proper amount of coolant in the system is the only way to go. Without it, you are committing your engine to a heinous act of self destruction.

  • The car lubrication chart says it has 7 liters next to coolant. I added 1 liter of coolant and 2 liters of tap water, drove 90 miles on the motorway but temperature gauge stayed in normal position as far as I can remember. I definitely experience high fuel consumption and lack of power which I believe are symptoms of a bad engine. Is it likely I have caused engine damage in this period of driving? May 9, 2018 at 10:18
  • @JamesWilson - It would be my "guess" ... yes, you caused damage to your engine. To what extent, who knows. If, after you get your coolant up to level, you find you have a mixing of coolant/oil (either coolant in crankcase or oil in the radiator), then you know you've got serious issues. If not, get your coolant where it needs to be and consider yourself lucky. May 9, 2018 at 11:12

Ill take it from here- paulster2-...... Why didn't you put 6liters of water? Or 5 Or 4 Or 3 and so on? That's a ridiculous question and deserves a ridiculous answer. I'm not sure why you werent 'advised' by the 'shop' to put water but there's no car or truck that's gonna render inoperable because you put more water than coolant in an emergency. You certainly were lucky.. And we advise you if you haven't done so by now to fill your 7liters with the factory recommended liquid.

  • there was only 1 liter of coolant available in the shop hence resorting to water. we put 3 liters of liquid cos we assumed that was enough. May 11, 2018 at 1:20

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