In recent vehicles, a sub-cool type condenser is used to improve the cooling capability.
In the refrigeration cycle of the sub-cool condenser, a modulator functions as a receiver/dryer and stores the liquid refrigerant inside the modulator. In addition, the refrigerant is cooled further at the overcooling part to be almost completely liquidized, so the cooling capability improves. In the modulator, a filter and desiccant that eliminate moisture and foreign matter exist in the refrigerant.
To replace the desiccant and filter in the modulator, discharge the refrigerant and then remove the cap.
In the sub-cool cycle, the point where bubbles disappear is before the cooling capability stabilizing range, which requires 100 g more refrigerant to reach the appropriate filling amount. If filling of refrigerant stops at the point where bubbles disappear, cooling capability is not enough. Further, overcharging decreases fuel economy and cooling capability, so be sure to fill the appropriate amount of refrigerant.