Renault Scenic 4

Renault's most-produced diesel with over 20 years of production history — with exemplary maintenance (oil every 10,000 km, fuel filter every 8,000–10,000 km) over 300,000 km is achievable. Biggest weakness: connecting rod bearings spin from around 100,000–150,000 km, especially with extended oil change intervals. Common-rail injectors (Delphi) and EGR valve are further service items.

• !! Connecting Rod Bearing Wear from 150,000 km

  The K9K connecting rod bearings are design-sensitive. With overly long oil change intervals or incorrect oil the bearing shells spin from around 100,000–150,000 km, resulting in total engine failure.

  Symptoms: Knocking engine noise, oil pressure warning light, sudden engine stop
  1,500–5,000 $
  Ad K9K connecting rod bearingK9K connecting rod bearingK9K crankshaftnlager
• !! High-Pressure Pump (Delphi) Failure from 90,000 km

  The Delphi high-pressure pump shows weaknesses from around 80,000 km. Metal wear from the pump contaminates the fuel circuit and damages the injectors and common rail — with consequential damage included.

  Symptoms: Starting difficulties, sudden engine stall, 'injection fault' message
  800–5,700 $
  Ad K9K high-pressure fuel pumpK9K Delphi fuel pumpK9K common rail pump
• !! Timing belt failure — engine destruction from 120,000 km

  The 1.5 dCi is an interference belt engine. With an overdue change interval or faulty fitting the belt snaps, valves and pistons collide — total loss. Early failures well before the scheduled interval are documented.

  Symptoms: Sudden engine stall without warning, refusal to start, metallic noises shortly before failure
  1,500–5,000 $
  Ad timing belt kit 1.5 dCitiming belt K9Kwater pump timing belt K9K

+ 5 more engine weaknesses + vehicle weaknesses

Modern 1.6-litre common-rail diesel with timing chain and up to 160 hp in the bi-turbo version — constructively complex and repair-intensive when damaged. Timing chain frequently elongates from 140,000–150,000 km; piezo injectors, EGR valve and DPF are known trouble sources. Only buy with complete service history and after engine inspection.

• !! Timing Chain Stretch from 145,000 km

  The R9M timing chain sometimes stretches from as early as 140,000–150,000 km, despite a stated 250,000 km service life. Chain failure leads to valve contact and total engine damage — a costly risk.

  Symptoms: Rattling noise on cold start, engine warning light, harsh engine noise
  800–3,500 $
  Ad R9M timing chainRenault 1.6 dCi timing chainR9M chain tensioner
• !! Connecting Rod Failure (Condensation Water) from 80,000 km

  The R9M 452 repeatedly suffers connecting rod failures attributed to condensation water ingested from the intercooler. Short oil change intervals and frequent short trips increase the risk.

  Symptoms: Loud knock from the engine, sudden engine stop, oil pressure loss
  4,000–15,000 $
  Ad R9M connecting rodRenault 1.6 dCi connecting rodR9M Motorschaden
• !! EGR Cooler Crack / Coolant Loss from 100,000 km

  The EGR cooler on the R9M is prone to cracking, allowing coolant to enter the intake system. The result is not only power loss but in extreme cases engine damage from water ingestion.

  Symptoms: Coolant loss without visible cause, white smoke, exhaust smell in the cabin
  1,200–2,500 $
  Ad EGR cooler R9M 147355224REGR cooler R9M 147350264R

+ 5 more engine weaknesses + vehicle weaknesses

Newer Euro 6d evolution of the diesel four-cylinder with SCR cat and AdBlue system — good performance and low consumption, but the AdBlue injection system is a documented problem source. Keep an eye on fuel injectors and cooling system; regular AdBlue quality check and coolant level check recommended.

• !! Turbocharger Failure from 120,000 km

  The R9N shows similar turbocharger problems to the R9M. Drivers report turbo faults at mid-range mileage — according to user reports more frequently than its predecessor the R9M.

  Symptoms: Whistling noises, power loss, limp mode, blue smoke
  800–2,000 $
  Ad R9N turbochargerRenault 1.7 Blue dCi Turbo
• !! Recall: Fuel Line Fire Hazard

  R9N engines (build year 11/2018–06/2019) were recalled due to non-specification fuel lines. Leaking lines can cause fuel spillage and fire hazard.

  Symptoms: Fuel smell in the engine bay, visible leaks
  0–500 $
  Ad R9N KraftstoffleitungRenault 1.7 Blue dCi fuel line recall
• !! AdBlue System / SCR Catalytic Converter Fault from 80,000 km

  The 'Blue dCi' system on the R9N suffers from problems with AdBlue injection and the SCR catalytic converter. This is the most frequently reported weakness and is considered not yet fully mature.

  Symptoms: AdBlue warning message, increased AdBlue consumption, engine power reduction when tank is empty
  400–2,500 $
  Ad R9N AdBlue fuel injectorRenault 1.7 dCi SCR catalytic converterR9N AdBlue Dosierventil

+ 2 more engine weaknesses + vehicle weaknesses

Widely used 1.2 TCe four-cylinder with a structural problem: the oil pump intermittently under-supplies the timing chain tensioner, leading to chain rattle, camshaft adjuster wear and increased oil consumption. Consumption over 1 l/1,000 km is not uncommon. Always check oil consumption before purchase and listen for chain noise.

• !! Timing Chain Stretches Prematurely from 60,000 km

  The most well-known H5F problem: the timing chain stretches significantly — especially with short-trip use or missed oil changes — potentially causing rattling and engine damage from 70,000–100,000 km. Oil dilution from short trips accelerates wear.

  Symptoms: Rattling on cold start, clattering on load changes, camshaft control fault code, engine damage
  2,500–8,000 $
  Ad timing chain kit 1.2 TCe 130C12345Rtiming chain H5F 130253326R
• !! High Oil Consumption from 40,000 km

  The H5F consumes increasing amounts of oil over its service life, often through worn piston rings or leaking valve stem seals. Values of 0.5–1.5 litres per 1,000 km are known from forum reports.

  Symptoms: Oil level visibly drops between changes, blue smoke on acceleration
  500–5,000 $
  Ad H5F piston ringsH5F valve stem sealsRenault 1.2 TCe oil consumption
• !! Turbocharger Failure from 100,000 km

  The H5F turbocharger suffers from oil supply problems, worsened by oil dilution from short trips and extended change intervals. Turbo damage is expensive.

  Symptoms: Whistling from the turbo, blue smoke, power loss, no boost build-up
  1,000–3,500 $
  Ad H5F turbochargerRenault 1.2 TCe Turbo

+ 5 more engine weaknesses + vehicle weaknesses

A 1.3-litre turbo developed with Daimler, with a timing chain and clearly improved reliability over the 1.2 TCe. Weak points are the wastegate linkage of early years (before the mid-2020 factory revision), the leaking thermostat housing and the intake-valve coking typical of direct injection. Ignition coils and spark plugs fail earlier than expected — a check from 60,000 km is sensible. With good oil care a solid, everyday-capable engine.

• !! Timing Chain Early Wear from 120,000 km

  The H5H 1.3 TCe also shows initial timing chain rattling in 2019 models after 50,000–70,000 km. Chain tensioners in particular wear prematurely and must be replaced.

  Symptoms: Rattling on cold start, clattering on load changes, camshaft control fault code
  800–2,000 $
  Ad H5H 1.3 timing chainRenault 1.3 TCe timing chainH5H chain tensioner
• !! Wastegate Failure After 80,000+ km from 60,000 km

  The wastegate valve of the H5H 1.3 TCe turbocharger wears after 80,000–100,000 km, causing power loss and increased oil consumption.

  Symptoms: Power loss, no boost build-up, whistling from the turbo area
  300–2,500 $
  Ad H5H 1.3 turbochargerRenault 1.3 TCe TurboH5H wastegate actuator
• !! Thermostat housing leak from 70,000 km

  The thermostat housing and its seals start to leak and coolant is lost without a visible external leak. Ignored, it risks overheating. The fault pattern and the part are known from the identical Mercedes engine.

  Symptoms: Coolant loss without visible leak, overheating warning, fault code P0128
  300–900 $
  Ad thermostat housing 1.3 TCethermostat 1.3 TCethermostat seal 1.3 TCe

+ 2 more engine weaknesses + vehicle weaknesses