temperature idiot light enough ?

[yaris-?]

is there also a low coolant warning or do you just cross your fingers & hope it doesn't overheat ?

[Shroomster]

there is a green light that stays on until the coolant reaches a pre-set temp then it turns off....if you are low or overheating starts, there is a red light that will turn on (exactly the same as the green only red)

[Bob_VT]

First I would suggest you read the owners manual for what all the lights mean.

Second I would strongly reccommend that you invest in a sacn gauge II which will display water temp among other great information.