Renault K4J / K4M 1.4 and 1.6 16vVariable valve timing (VVT) actuator
Variable valve timing unit failure (dephaser pulley) on the 1.4 and 1.6 16v
Why this rating?
Medium severity: It can leave you stranded or get worse if ignored, without destroying the engine.
Frequency occasional: Fiches-auto.fr documents the "poulie déphaseur" in more than 12 of the 83 testimonies for the Mégane II with the 1.6 16V, in 3 of the 55 for the Scénic II (with one case at 152,000 km), in 4 of the 77 for the Scénic I, in 2 for the Mégane III and in 1 case for the Clio III ("claque au démarrage et perturbe le calage variable"), as well as cases described in the Laguna II. It is a minority in every case (between 4% and 14% of the testimonies for each model), but it recurs independently in at least five different generations of the engine with the variable valve timing unit, which makes it an occasional, known fault, not an isolated case.[1][2][6][7][8][9]
Symptoms
- Metallic knocking or "claquement" around the timing area on start-up, described by the sources as linked to the variable valve timing unit's pulley.[6]Chain noise: other faults that cause it · Garage soon
- Cold starting harder than normal when the variable timing unit or its position sensor starts to fail.[1]Hard to start: other faults that cause it · Garage soon
- Unstable idle ("ralenti instable") linked by the sources to failure of the variable timing unit's pulley.[2]Vibrations: other faults that cause it · Monitor
- Metallic knocking or "claquement" around the timing area on start-up, described by the sources as linked to the variable valve timing unit's pulley.[6]Noise on start-up: other faults that cause it · Garage soon
Why it happens
The sources attribute the failure to the pulley of the variable valve timing unit (déphaseur) on the intake camshaft, on occasion together with its associated position sensor, without always detailing whether the origin is the pulley's own internal mechanism or the sensor.[1]
If it is not repaired: Unstable idle, harder cold starting and, in some cases, the engine warning light on; the sources consulted do not describe damage to other engine parts beyond the pulley itself and, where applicable, the associated sensor.[1][2]
Affected cars and years
It only affects K4M versions with a variable valve timing unit (variable timing) on the intake camshaft; we do not find this fault documented in the Dacia calibration (Logan, Duster), which according to the sources consulted has no variable valve timing unit, nor in the 1.4 K4J.[3][4][5]
| Version | Years | Codes |
|---|---|---|
| 1.6 16V 110-135 hp with variable valve timing unit (K4M, 1998-2020) | since 1998 | K4M |
Models fitted with the affected versions
Renault
- Renault Clio II1998–2012
- Renault Clio III2005–2012
- Renault Mégane I1995–2002
- Renault Mégane II2002–2009
- Renault Mégane III2008–2016
- Renault Scénic I1996–2003
- Renault Scénic II2003–2009
- Renault Kangoo I1997–2007
- Renault Laguna II2001–2007
- Renault Fluence2010–2016
- Renault Scénic III2009–2015
How much it costs to repair
Includes: Diagnosis and replacement of the variable timing unit's pulley; in practice the same job is usually used to change the timing belt too, as it requires a similar strip-down of the front of the engine.[1]
A testimony collected by fiches-auto.fr for the Mégane II puts the part at around €200 plus the timing belt change, but it is not a systematically published figure and does not break out labour, so we do not use it as a reliable cost figure for Spain.
Prices in Spain, including VAT. A workshop hour costs on average €38–66 at independent garages and €77–134 at dealerships in Spain, depending on the region and the brand. How we calculate costs
How to check for it before buying a used car
- Start from cold and listen for a metallic knock at the front of the engine, and check that the idle is stable.
Parts needed
The part or kit that fixes this fault, according to the sources.
- Buy part at Autodoc (affiliate link, opens in a new tab)
Variable valve timing unit pulley (déphaseur)
Replaced when it causes unstable idle, knocking on start-up or the engine warning light on because of poor variable timing.
Affiliate links to Autodoc: if you buy, MotorFiable may receive a commission at no cost to you. Check compatibility using the registration number or the VIN before ordering. More information
How to prevent it
- If you have to change the timing belt by mileage, ask the garage whether it is worth checking the variable valve timing unit's pulley at the same time, as both parts share the same fitting area.
Recalls, campaigns and claims
As of 27 September 2026, we have no record of recalls, campaigns or extended manufacturer warranties for this fault. Check with an official dealer using the chassis (VIN) number: they will tell you whether the car has any outstanding campaign.
What owners say
Frequently asked questions
What is the variable valve timing unit's pulley and why does it fail?
It is the mechanism that adjusts the intake camshaft's timing according to engine speed. The sources document its failure in several generations of Clio, Mégane, Scénic and Laguna with this engine, without always detailing the exact technical cause.[1][2]
What can you do now?
We will put you in touch with a partner only if you authorise it in the form.
Other 1.4 and 1.6 16v faults
- Medium severityFrequency: Very frequentIgnitionIgnition coil failureThe individual ignition coils are the most-cited fault of the K4J/K4M in the European Renault versions: they fail frequently and cause jerking, loss of power and the engine warning light coming on. It is a cheap electrical part to replace, not internal engine damage.Appears at around 30,000 km
- High severityFrequency: OccasionalTimingTiming belt breakage or premature failureThe K4J/K4M's timing belt is a dry type (not running in oil), but several sources document breakages before high mileage is reached, including one case in the Renault Laguna II with valve-to-piston contact. Sticking to the replacement interval is the best prevention.Appears at around 89,000 km
- Medium severityFrequency: CommonElectronicsCrankshaft position sensor failureThe crankshaft position sensor (capteur PMH) appears repeatedly in the reliability sources for almost every generation with this engine, with hard cold starting, stalling or the car cutting out unexpectedly. It is a cheap part, but the failure can leave you stranded.
- Low severityFrequency: RareLubricationOil consumption (no documented pattern on this engine)Unlike many modern turbo engines, the sources consulted for the K4J/K4M do not describe a pattern of excessive oil consumption in any of the cars or versions covered by this page.
More faults with the variable valve timing actuator on other engines and cars
- High severityFrequency: OccasionalPorsche V8 and V6 (Cayenne and Panamera)Loosening of the camshaft adjuster boltsPorsche acknowledges that the fixing bolts of the camshaft adjusters on certain Cayenne S and Turbo and Panamera models built up to September 2011 can fail: noise, vibration, engine warning light and, in rare cases, stalling. There has been a worldwide workshop campaign since 2012.
- Medium severityFrequency: CommonBMW N43/N46Wear of the Valvetronic and the VANOS solenoid valvesOver the years, the eccentric shaft or the actuator motor of the Valvetronic can wear and cause heavy idle fluctuations; the VANOS solenoid valves also fail over time, with similar symptoms and a loss of power. According to English-language Wikipedia, the 1.6-litre N43B16 does not have Valvetronic.
- Medium severityFrequency: CommonM111Camshaft adjuster oil leak into the wiringYes: the magnet (solenoid valve) of the M111 camshaft adjuster can lose its seal, and the oil creeps up by capillary action to the connector and the wiring loom. Mercedes-Benz has the same repair cable as for the M271 (part number A2711502733), which is cheap to fit.
- Medium severityFrequency: CommonM271Oil leaking from the camshaft adjuster solenoids into the wiringYes: the camshaft adjuster solenoids (magnets) of the M271 can lose their seal, and the oil wicks up to the connector and the wiring loom, and can even reach the control unit. Mercedes-Benz has a specific repair cable (reference A2711502733) that is cheap to fit.
- Medium severityFrequency: CommonM270/M274Oil leaking from the camshaft adjuster into the electrical connector (M274)Yes: on the M274, the camshaft adjuster solenoids can lose their seal over the years and let oil wick up to the connector and the wiring harness, potentially reaching the ECU. It is fixed relatively cheaply with a specific repair cable.
- Critical severityFrequency: Rare1.2 and 1.4 TSICamshaft adjuster and belt failure (EA211, 2013-2015)On some 1.2 TSI EA211 engines built mainly in 2014, the camshaft adjuster bolts came loose, jammed the wheel and snapped the belt, causing serious engine failure. Volkswagen recalled units from late 2013 to 2015 (action 15H2).
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Sources
Every fact on this page links to its source. If you find an error, let us know.
- Fiabilité et pannes de la Renault Mégane 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
- Fiabilité et pannes du Renault Scénic 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
- Anexo:Motores de RenaultWikipedia (español) · Other source · consulted 27 September 2026 · in Spanish
- Fiabilité et pannes du Dacia Logan 1Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
- Fiabilité et pannes du Dacia Duster 1Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
- Fiabilité et pannes de la Renault Clio 3Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
- Fiabilité et pannes de la Renault Mégane 3Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
- Fiabilité et pannes du Renault Scénic 1Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
- Fiabilité et pannes de la Renault Laguna 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French