do i need to put water in the radiator

They sell a cheapo tester at auto zoo but it doesn't tell you if it's a 50/50 mix only the temp it's good for . You'd have to gauge it against a 50/50 mix to see . Coolant level like oil should be checked now and then , the one one time you don't it'll be low indicating a problem

In most applications, a 50/50 mixture of antifreeze and water works well and should be checked by looking at the overflow tank outside of the engine. There should be 2 marks on the tank. One to use if the engine is at operating temp and one if the engine is cold. If you used a pre-mixed bottle of antifreeze and water mixture or a mixture you made yourself, you should check the level first and then add more if it does not come up to the indicator on the overflow bottle. A good practice is to check it every month and change the coolant every 2 years or 20K miles.