
Reasons for the 307's air conditioning not cooling: 1. Condenser: The condenser is a component that is often overlooked. After prolonged driving, a lot of dust accumulates on the condenser. If the car is frequently driven on dusty roads, even more dust will gather on the condenser. Excessive dust on the condenser significantly reduces its cooling efficiency, leading to poor air conditioning performance. 2. Damage to the air conditioning compressor, throttle valve, or expansion valve: The probability of the air conditioning compressor failing is relatively low, but faults in the expansion valve or throttle valve can directly cause poor cooling. 3. Lack of refrigerant: The sealing of the air conditioning system is not absolute, so the refrigerant tends to dissipate over time. Therefore, most vehicles require refrigerant replenishment every 2-3 years. If the car's air conditioning and cooling equipment are not functioning well, the cooling performance may start to deteriorate shortly after refilling the refrigerant. In such cases, the condenser might be leaking.

I've been driving my 307 for almost ten years and have encountered air conditioning failures twice. The most common issue is refrigerant leakage. In my case, it was due to aging AC pipe joints leaking refrigerant, and the high-pressure pipe didn't feel cold at all. The compressor failure is the most troublesome - you should be alert if you don't hear the 'click' engagement sound from the engine compartment when pressing the AC switch. Clogged radiator fins by willow catkins can also prevent cold air output, so I wash the condenser with a water gun every spring. Electrical problems shouldn't be ignored either, like that thumb-sized AC relay with poor contact - replacing it only costs about twenty yuan. By the way, a blocked expansion valve will make the vents blow natural air, and this requires dashboard removal to fix.

With 15 years of experience repairing French cars, 307 air conditioning faults mainly fall into three categories: refrigeration cycle issues account for 70%, including insufficient refrigerant, compressor seizure, or condenser blockage; 20% are electrical problems, such as pressure switch failure causing the compressor not to start; the remaining 10% are mechanical failures. Focus on checking the low-pressure pipe pressure, which should normally be around 3 kg; too low indicates a refrigerant leak. Remember to use a diagnostic tool to read the air conditioning module fault codes—Peugeot cars often report 'pressure inconsistency' errors. The most troublesome issue is evaporator leaks, requiring the entire dashboard to be removed. It's recommended to first replace the air conditioning filter, which can solve 30% of airflow problems for just thirty bucks.

Last month, I just fixed the AC issue in my 307. First, I checked the electrical circuit: after ignition, I pressed the AC button to see if the compressor clutch engaged. If there was no response, I inspected the fuses and relays. For the refrigeration cycle, I observed the sight glass on the dryer bottle—excessive bubbles indicated a refrigerant shortage. Pay special attention to the pressure switch attached to the condenser, as it often triggers false alarms. For the mechanical part, I felt the temperature difference between the high and low-pressure pipes. If the high-pressure pipe was hot while the low-pressure pipe wasn’t cold, it was likely a clogged expansion valve. For older cars, it’s also important to check if the compressor belt is slipping. Don’t rush to recharge the refrigerant—finding the leak point is more crucial.

When the air conditioning system of the 307 is operating, the refrigerant is compressed into a high-temperature gas by the compressor, then dissipates heat and liquefies in the condenser, is filtered by the dryer bottle, and finally atomized and absorbs heat through the expansion valve. Any malfunction in these components can lead to a lack of cooling: worn compressor pistons lose their pressurization capability; a condenser covered in dirt affects heat dissipation; saturated desiccant in the dryer bottle can freeze and cause blockages; a stuck expansion valve allows liquid refrigerant to rush directly into the evaporator. A malfunctioning temperature sensor in the control circuit can also cause the computer to misjudge. It is recommended to use an infrared thermometer to check the temperature difference in the pipelines—the normal temperature difference between the high and low-pressure pipes should be above 40°C.

Every May, there's always a wave of 307 owners coming in for air conditioning repairs. The most common issue is slow refrigerant leakage, especially in older cars over ten years where the rubber seals have hardened. Preventive maintenance is crucial: clean the condenser fins every two years using specialized foam spray to avoid damaging the cooling fins; check for oil stains at pipeline joints before each summer; replace the dryer bottle every 40,000 kilometers. For electrical aspects, focus on maintaining the AC button contacts—many cars fail to start due to poor switch contact. Cars with modified central control screens should have their AC signal lines checked to ensure they weren't accidentally disconnected. Remember, using recirculation mode cools the cabin twice as fast.


