Turbocharger faults in the Renault Kadjar lead to loss of power, smoke and high fuel consumption due to lack of oil or carbon build-up. Models with the 1.5 dCi and 1.2 TCe engines in particular regularly suffer from these problems, sometimes already at relatively low mileages. Do you recognise these symptoms? Then it’s time to take action before the damage gets worse.
How to recognise a faulty turbo
A failed turbocharger usually makes itself known fairly quickly while driving. The most common sign is an illuminated engine warning light on the dashboard. This light is often accompanied by fault codes indicating problems with turbo boost pressure measurement or control of the turbo. You’ll notice that the engine feels less powerful, especially when accelerating.
Another common symptom is a whistling or whining noise from under the bonnet. This sound is especially audible at higher speeds, often above 140 kilometres per hour, or when you accelerate at higher revs. It usually points to leaks in the intake or exhaust system, or to a sticking turbo. Don’t ignore this sound, as it can lead to total failure of the turbocharger.
Loss of power while driving is also a clear signal. The Renault Kadjar then responds sluggishly to the accelerator pedal and feels as if not enough boost pressure is being built up. Other signs are oil in the intake tract or intercooler, smoke from the exhaust and higher-than-normal fuel consumption.
Causes of turbo failures
The turbocharger in the Renault Kadjar is sensitive to various types of faults. One of the main causes is dirty or insufficient oil. The turbo runs at extremely high speeds and needs constant, adequate lubrication. When the oil level is too low or the oil becomes contaminated, the bearings wear quickly and the turbo can overheat.
Issues with air quality also play a role. A dirty air filter causes imbalance in the turbine, making it work less efficiently. In the long term this leads to wear and reduced performance. On diesel engines this often occurs in combination with carbon deposits in the intake system.
Other common causes are:
- Defective actuator or pressure sensor that does not correctly control the boost
- High back pressure due to a clogged diesel particulate filter (DPF) on the diesel version
- Problems with the VNT lever, the system that controls the variable geometry of the turbo
- Overloading due to prolonged high-rev driving or too many short trips without a warm-up phase
- Leaks in hoses or joints around the intake system
Why the Kadjar loses power under acceleration
Loss of power during acceleration in the Renault Kadjar is often caused by insufficient boost pressure. The turbocharger then fails to build enough pressure to supply the engine with sufficient air. This can be due to a faulty boost pressure actuator or a failing MAP sensor (intake air pressure sensor), which measures the airflow and pressure in the intake system.
Carbon build-up is another major cause of power loss. These deposits form in the intake system and on the valves, especially on engines that do a lot of short trips. The deposits restrict airflow and prevent the engine from performing optimally. Diesel engines such as the 1.5 dCi are particularly sensitive to this.
Owners also report that actuator problems cause loss of power. The actuator controls the variable geometry of the turbo. When it seizes up or fails electrically, the turbo can no longer deliver the correct pressure. This problem occurs regularly with the 1.5 dCi engine and leads to noticeably reduced pulling power.
How much does turbocharger repair cost
The cost of turbo repairs on the Renault Kadjar varies considerably. Replacing a complete turbocharger including labour quickly costs between €1,200 and €2,500, depending on engine type and whether you choose an original or reconditioned unit. Diesel engines such as the 1.5 dCi are often at the higher end of this range.
Fortunately, a complete replacement is not always necessary. When only the actuator is defective, the repair usually costs between €300 and €600. Cleaning the intake system and intercooler generally costs €200 to €400. These preventive measures can prevent much more expensive damage and are therefore worthwhile.
Be aware that some garages advise replacing the whole turbo straight away, whereas a repair or cleaning is sometimes sufficient. Always ask for a thorough diagnosis before agreeing to major repairs. It’s also sensible to compare several quotes, as price differences between garages can be significant.
‘ Checking the oil level is the most important step. ’
Preventive maintenance avoids problems
Regular maintenance significantly extends the life of the turbocharger. Checking the oil level is the most important step. Check it at least once a week and make sure you always drive with the correct oil level. Change the oil and oil filter every 10,000 to 15,000 kilometres using quality oil that meets Renault’s specifications.
The air filter also deserves regular attention. Replace it according to the service schedule, usually every 20,000 to 30,000 kilometres. A clean air filter ensures optimal airflow and prevents contamination of the turbo. On the diesel version it’s wise to have the intake system and intercooler cleaned at around 50,000 kilometres.
Your driving style also affects the turbo’s lifespan. Always let the engine warm up before using full throttle, especially in cold weather. Where possible, avoid lots of short journeys where the engine does not reach operating temperature. With diesel engines, regularly use premium fuel to help prevent blockage of the diesel particulate filter (DPF), which indirectly protects the turbo.
Diagnosis and next steps for turbo problems
If you suspect the turbocharger is defective, first have a thorough diagnosis carried out using an OBD scanner. This scanner reads the fault codes and shows which sensors or actuators (control mechanisms) are reporting issues. When analysing, focus on the turbo boost pressure readings, the wiring to the actuator and any leaks in the intake system.
If you hear a whistling noise, it’s important to stop immediately and not continue driving. First visually check for leaks around the VNT lever (lever of the variable turbo geometry) and the crankcase ventilation. Also check the oil level, as too little oil can quickly cause serious damage. Do not attempt to clean the turbo yourself without knowing the actual cause.
Never continue driving with an illuminated engine warning light linked to the turbo. This can lead to serious engine damage that is far more expensive than a timely repair. Have the car taken to a specialist with experience of Renault engines and turbo systems. Specifically ask for the cylinder head to be checked when there are MAP sensor problems, as the root cause is sometimes deeper than just the turbo itself.
Experiences of Kadjar owners
On forums, owners regularly share their experiences with turbocharger failures. Several users report that their turbo failed at around 85,000 kilometres, with no compression left in the cylinders due to oil-related wear. Owners of low-mileage cars also suffer turbo failure due to carbon build-up, which often isn’t covered under warranty because it’s regarded as wear and tear.
Diesel Kadjar drivers with the 1.5 dCi engine often experience actuator failures resulting in loss of power. The solution usually turns out to be replacing the actuator, which is much cheaper than a complete turbo. Owners advise each other to have the turbo inspected immediately if a whistling noise occurs above 140 kilometres per hour, as ignoring it often leads to total failure.
‘ Fortunately, with preventive maintenance and timely intervention you can avoid a lot of damage. ’
Find out more about the Renault Kadjar
Turbocharger faults are serious issues that demand prompt attention. Fortunately, with preventive maintenance and timely intervention you can prevent a lot of damage. On the Carnews website you’ll find much more information about common faults, maintenance advice and practical tips for the Renault Kadjar and other car models. Discover what other owners are experiencing and learn how to keep your car in top condition.
Frequently asked questions
Typical symptoms of a turbocharger fault on a Renault Kadjar include an illuminated engine warning light in combination with fault codes relating to turbo pressure or control, and clear loss of power or disappearing “boost”. You often hear a whistling or whining noise when accelerating or at higher speeds, sometimes accompanied by jerky running. Oil can also end up in the intake tract or intercooler, which shows up as increased oil consumption and/or smoke from the exhaust. In some cases you may also notice exhaust fumes inside the cabin.
Common causes of turbocharger problems on the Renault Kadjar include dirty or insufficient engine oil, which leads to overheating and bearing wear in the turbo. In addition, blocked or dirty intake and exhaust passages (such as DPF or VNT issues) create excessive back pressure and incorrect turbo boost. Defective actuators or sensors (such as the boost pressure actuator or MAP sensor) also cause boost loss and warning lights. Overloading due to frequent high revs and short trips without proper warm-up further accelerates turbocharger wear.
After a cold start, allow the engine to warm up gently and avoid high revs or full throttle while the engine is still cold. Change the oil and oil filter more frequently than the factory schedule (for example every 10,000–15,000 km) using good-quality oil, and check the oil level regularly. Ensure a clean air intake (replace the air filter on time) and, at higher mileages, have the intake system and intercooler checked/cleaned preventively. Do not continue driving with a whistling noise, loss of power or an illuminated warning light; instead, have the turbo, actuator and intake/exhaust system checked professionally straight away.
The main options are: (1) overhauling the existing turbocharger, where it is dismantled, cleaned and rebuilt with new bearings and seals; (2) fitting an exchange turbo (factory-reconditioned turbocharger); or (3) complete replacement with a new original or aftermarket turbocharger. Overhaul is usually the cheapest option (roughly €400–€900 including labour), an exchange turbo is typically mid-range (around €700–€1,300), while a brand-new turbo is often the most expensive (about €1,000–€2,000 or more, depending on the type and make of car).
Yes, there are known turbocharger problems on the Renault Kadjar, especially with the 1.5 dCi and 1.2 TCe engines, such as premature wear, pressure loss and whistling/whining noises due to leaks or actuator issues. Oil-related problems (dirty or insufficient oil) and carbon build-up in the intake system are relatively common and can lead to power loss and engine warning lights. Whistling noises at higher speeds (around 140 km/h) and oil in the intercooler are typical warning signs that should be taken seriously. Strict and timely maintenance (oil and filters, checking intake/exhaust and actuator) is essential to limit or prevent turbo damage.
Ignoring a turbocharger fault on your Renault Kadjar can lead to accelerated wear or seizure of the turbo, partly due to oil or pressure problems. As a result, engine power decreases and fuel consumption and smoke emissions may increase. If you carry on driving for too long, you risk serious engine damage, such as damage to bearings, intercooler or even cylinders. Have the fault read out and rectified professionally as soon as possible to avoid high repair costs.