Air-conditioning in modern cars is now a standard feature. If, however, you want to be sure that the air in your car is nice and clean, you must take good care of the cooling system. One of the most common causes of its failure are leaks. Therefore, you should have it checked regularly to avoid them. One of the most effective methods of checking if the cooling system is tight is the pressure method, which consists in sucking the cooling agent out of the system and filling it with high-pressure nitrogen to create a vacuum. If the system is unable to hold the vacuum for a specific period of time, it means that its tightness has been compromised.