Whether you have enough cooling fluid in your Ranger or not, you may get air into the coolant lines from time to time. But just because you see a bubble in the coolant line doesn’t mean you have air in there. Furthermore -- and counterintuitively -- it is highly unlikely that a low coolant reservoir is going to introduce air into the coolant system. Polaris Ranger Mid-Sizes are designed to pull coolant into the radiator if the reservoir gets low, and if it catches any air, it will usually push it out. When the cooling system doesn’t push out the air by itself, you can help it out by “burping” the cooling system. To do this, first park your Ranger on an incline raise the front end a foot or two with a jack. Take the radiator cap off and let the Ranger run. Right before the fan cuts on the cooling system will start burping, so watch out lest you get scalded. After the fan cuts on you need to add coolant. Repeat this procedure until you have no burping and the level doesn't drop in the radiator when the fan cuts on.
In addition to getting air into the cooling lines, radiator obstructions can also cause your Mid-Size Ranger to overheat. Winches, light bars, and other accessories can block airflow to the radiator, and mud / dirt can get caked onto it and cause it to underperform. Keep this in mind when considering aftermarket accessories for your Ranger that might block the radiator.
Shop 2019 Ranger Models: 2019 Ranger 500 Cooling System | 2019 Ranger 570 (Pro-fit Bars) Cooling System
Shop 2020 Ranger Models: 2020 Ranger 500 Cooling System | 2020 Ranger 570 (Pro-fit Bars) Cooling System
Shop 2021 Ranger Models: 2021 Ranger 500 Cooling System | 2021 Ranger 570 (Pro-fit Bars) Cooling System