The air conditioning in the Dacia Logan MCV regularly cuts out, especially on cold starts. Pump noise and failed compressors are known issues. Without maintenance the compressor is damaged. That can lead to engine stalling. Find out why this happens and what you can do.
Why the aircon does not work on a cold start
Owners of the Dacia Logan MCV regularly report aircon faults during cold starts. The air conditioning system then provides no cooling. It can also fail completely. This issue is often caused by a failed compressor (the pump of the aircon system). The compressor struggles to get going. That happens when the system is cold.
Engine speed becomes irregular when the aircon is switched on. Owners report that the revs drop by around 200 rpm. After that they recover. This fluctuation occurs with various engine versions. It indicates the system is being overloaded.
The cause is often a combination of several factors. Refrigerant can leak away. The condenser (the heat exchanger at the front of the car) can also fail, or electrical faults can occur in the control unit. This leads to reduced performance at low temperatures. The dashboard warning light then comes on. There is a fault present in the system.
Recognising and fixing pump noise from the aircon
Many Logan MCV owners recognise pump noise when they have aircon problems. The aircon pump becomes damaged. The pump no longer runs smoothly. This creates noise. A lack of refrigerant causes this. The pump has to run without lubrication.
This noise presents as:
- A grinding or squeaking noise when the aircon is switched on
- A rattling noise that rises and falls with engine speed
- A whistling noise from under the bonnet while driving
Tackle this immediately. A damaged aircon pump can lead to engine stalling. The pump damages the engine itself. Repair costs then rise far above the cost of just replacing the pump. Have the system checked for leaks. Only then have it refilled with refrigerant.
Common causes of aircon faults
The air conditioning system in the Dacia Logan MCV regularly develops faults. Owners often report these issues with this model.
The main causes are:
- Failed condenser. Cooling capacity is reduced.
- Leaks in the system. Refrigerant leaks away.
- Failed mass air flow sensor (a sensor that measures the amount of intake air). This causes loss of power.
- Electrical faults in the control unit (the aircon control electronics)
- Damaged wiring loom. This creates the same faults as a failed sensor.
Some models do not have the receiver-drier integrated into the condenser. In that case the receiver-drier must also be replaced. This increases the repair costs. Otherwise the problem soon returns. Owners report that extensive diagnostics are sometimes needed. That is how the actual issue is identified.
What does an aircon repair cost?
The costs of aircon repairs on the Dacia Logan MCV vary depending on the issue. Topping up refrigerant costs a few tens of euros at a garage. Replacing a condenser costs a few hundred euros. Labour is included in that.
A failed compressor costs more. The parts alone cost a few hundred euros. On top of that there is labour for removing it. Refitting also costs labour. In some cases several components were replaced. The actual problem was only identified afterwards. Think of sensors that detect whether the flywheel is turning.
Avoid cheap repairs at garages without a good reputation. Non-original parts wear out faster. Problems return. An authorised dealer has access to the correct diagnostic equipment. They use original parts. In the long run that works out cheaper.
‘ It can even cause the engine to stall. ’
Consequences of untreated aircon problems
Ignoring aircon faults causes serious damage. The aircon pump becomes completely ruined. It can even cause the engine to stall. This damages the engine. The pump has to be repaired. Other components also have to be repaired.
The aircon does not operate properly. Fuel consumption increases. The system has to work harder to deliver the same cooling performance. This puts extra load on the engine. Costs at the pump go up. Fuel costs also rise.
Reduced cooling performance affects driving comfort. It also affects road safety. In hot weather the aircon does not work. Concentration behind the wheel decreases. Have minor faults repaired quickly. Otherwise they cause more serious damage.
Preventive measures and maintenance tips
Regular maintenance prevents many aircon problems. Have the system checked annually for leaks. Also check the amount of refrigerant. The compressor then does not run without lubrication. Damage is prevented.
Use only original parts. Replace spark plugs according to Dacia’s service schedules. Also replace the air filter and fuel filter. This helps the aircon. It also improves the car’s overall performance.
If the aircon causes persistent idle instability, have a shorter belt fitted. This bypasses the aircon pump. It is a temporary solution. Immediate replacement is not always possible. The problem is not permanently resolved.
Recognising warning signs
Recognise early warning signs. The dashboard warning light is the clearest sign. Something is wrong with the air conditioning system. Contact a garage straight away.
Other warning signs are reduced cooling performance and strange noises from under the bonnet. Rising fuel consumption combined with aircon use is also one of them. These signs point to problems with the compressor. The cooling system can also trigger these signs.
Watch out for changes in engine speed. This happens when you switch on the aircon. Large fluctuations indicate an overloaded system. A failed sensor can also cause this. Early detection makes repairs easier. Costly engine damage is avoided.
‘ Early diagnosis prevents severe engine damage. ’
When to go to the garage
Noticing warning signs? Then go to an authorised garage. Otherwise the problem will get worse. The aircon will fail completely. Early diagnosis prevents severe engine damage.
Choose a garage that regularly repairs Dacia aircon systems. These garages have access to the right diagnostic tools. They know the issues with the Logan MCV. This saves time. Multiple parts are not replaced unnecessarily.
The garage must examine the system thoroughly. Only then can they refill it with refrigerant. Fix leaks first. Otherwise the problem will return. Ask for a clear explanation of the issue. Also ask for an explanation of the proposed solution. Only then agree to the repair.
On the Carnews website you will find more information about car problems and maintenance tips. Want to keep your car in top condition? Discover more about maintenance. What issues can you expect with your model? Read about other owners’ experiences.
Frequently asked questions
The most common causes of aircon faults in a Dacia Logan MCV are a failed condenser (often together with the receiver-drier) and leakage of refrigerant from the system. In addition, electrical problems in the UCH (control unit) and faults in sensors or the mass air flow sensor are common. Damaged wiring can also cause the aircon to fail or to work poorly. Detecting and fixing leaks and electrical faults in good time often prevents more serious damage to the aircon pump.
First check whether the aircon switches on: listen to see if the compressor can be heard engaging and check whether the revs briefly change when you switch it on. Then check whether the fan works on all speeds and whether there is a temperature difference between aircon on/off with maximum cooling and recirculation mode. Look under the car to see if condensate drips after it has been running for a while; no condensate together with no cooling can indicate a refrigerant leak or compressor issue. If in doubt, always have the system pressure and any leaks checked with professional equipment, as this cannot be done safely and accurately yourself.
The average costs for repairing the aircon system of a Dacia Logan MCV are usually between about €300 and €800, depending on the cause of the problem. Replacement of just a condenser or fixing a leak is often at the lower end of this range, while combined repairs (such as condenser plus receiver-drier and diagnostics/labour) move towards the upper end.
Regular aircon maintenance (leak check, pressure measurement and timely replacement/refilling of the refrigerant) helps to prevent problems at an early stage. If you notice complaints or reduced cooling, have the system checked immediately to avoid damage to condenser and pump. When repairing, use only high-quality or original parts and avoid quick “fast fitter” solutions. Also keep up with general engine maintenance (spark plugs, filters) in line with the manufacturer’s schedule, because a poorly running engine can worsen aircon-related complaints.
On the Dacia Logan MCV, the aircon condenser fails relatively often, usually due to stone chips and corrosion, which cause refrigerant leakage. Leaks elsewhere in the system (hoses, couplings and O-rings) are also common, leading to insufficient pressure and poor cooling. In addition, electrical components around the control system (such as the UCH/control unit and sensors) can develop faults, causing the compressor not to switch on or to switch on irregularly. These defects are usually linked to ageing, exposure to dirt and moisture, and sometimes mediocre material or component quality.