Coolant

[alexiskai]

One benefit of antifreeze is that you can run any percentage of it you want- 20%, 33%, etc. - and you’ll get all the corrosion protection of antifreeze with a cooling capacity close to water. There are charts online where you can map the absolute lowest temperature you might see to the percentage antifreeze you need. This also means you don’t run the risk of forgetting to drain the coolant if an unexpected freeze occurs.