Radiator coolant.
Yes.
In radiator or through coolant recovery tank
Never put just straight water in your motor. You want to top off your radiator first then top off your coolant in the reservoir. Water will rust your motor from the inside out.
Yes you can put coolant right into the radiator. Just make sure it is a 50/50 mix of the correct anti-freeze and distilled water.
you add coolant to e150 thru the radiator overflow bottle
In the radiator
Yes, you can. But if you leave in cold area you will have to replace with proper coolant closer to winter. Otherwise it will damage not only your radiator but also the engine.
You add coolant to the reservoir and in the radiator cap.
put a 50/50 mix of coolant and water in your radiator
You don't, unless you are flushing the system. Use distilled water and add it to the coolant recovery bottle - and it needs to be mixed with coolant.
At the radiator or overflow tank. Do not add water, add coolant.