What Causes the Low-Pressure Pipe of Car Air Conditioning to Not Be Cold?

[DeMackenzie]

Car air conditioning low-pressure pipe not being cold is caused by: 1. Insufficient air conditioning refrigerant; 2. Inadequate air conditioning pressure or refrigerant line leakage. The car air conditioning system is a device that cools, heats, ventilates, and purifies the air inside the vehicle compartment. Its functions are: to provide a comfortable riding environment for passengers, reduce driver fatigue, and improve driving safety. The car air conditioning consists of a refrigeration system, heating system, air purification device, and control system, designed to adjust and control the temperature, humidity, air cleanliness, and air flow inside the vehicle compartment to an optimal state.

[VonMadison]

I've encountered the issue of the A/C low-pressure pipe not being cold several times, and it's quite a headache. Generally speaking, the main cause is insufficient refrigerant. The air conditioning system relies on refrigerant to produce cold air, which is why the pipe should feel cold. If there's a leak in the system—such as loose pipe connections or aging seals—the refrigerant will gradually leak out and fail to function. The compressor could also be faulty, for example, due to internal wear or a malfunctioning clutch, preventing it from properly compressing the gas. If the expansion valve is clogged, refrigerant flow is obstructed, and the pipe naturally won't get cold. Additionally, a dirty A/C filter blocking airflow can also affect overall performance. When checking, you can first feel the pipe's temperature and listen for any unusual noises from the A/C operation. I recommend getting it inspected at a repair shop as soon as possible—otherwise, driving in summer can become unbearably hot, affecting comfort and safety. Regular vehicle maintenance can help avoid many such issues.

[Duarte]

I think it's quite common for the A/C low-pressure pipe not to be cold, based on my own experience. It could be due to insufficient refrigerant, making the system ineffective once it's running. Or there might be a leak, especially in older cars which are prone to gas leakage. If the compressor isn't working properly, like a loose belt or aging parts, it can't supply gas normally. Problems with the expansion valve can also block the path, preventing refrigerant from passing through. A dirty condenser that hasn't been cleaned, leading to poor heat dissipation, is another possible cause. For a preliminary check: start the A/C and feel the low-pressure pipe where it should be cold; if it's not, there might be an issue. Also, listen to see if the compressor sound is steady. If you notice anything wrong, don't push it, and get a professional to check it out promptly. Keeping the A/C well-maintained ensures a comfortable drive, so don't ignore small issues that could turn into big risks. Regularly checking the refrigerant level and taking preventive measures is key.

[SanRobert]

Last time, the air conditioning in my car had an issue where the low-pressure pipe wasn't cold at all, which was quite frustrating. Initially, I thought the refrigerant had run out, but the actual cause was more complicated—it might have been a system leak causing the refrigerant to escape. Compressor failures are also common; if the components are damaged, they won't function. When the expansion valve gets clogged, the refrigerant gets stuck and can't flow. I also encountered a situation where the condenser was too dirty and hadn't been cleaned, reducing its cooling efficiency. During the check, I tried a simple method: turning on the AC for ten minutes—the pipe should have been cold, but there was no temperature change. Adding refrigerant later solved the problem, but if that hadn't been the cause, professional diagnostics would have been needed. Don't delay fixing it for too long.