I purchased my 2020 Sportage in June 2109. I have 11,000 miles on the car. In checking the washer fluid today I noticed the coolant reservoir was below the minimum line. I live in Houston. So could this be why it is low? Should it be this low? I haven't noticed any leaks in the garage. Can I top it off or do I need to drain it and refill it? What do I refill it with?