Mazda 5
2.0-litre common-rail diesel in various development stages (RF4F, RF5C, RF7J). Solid everyday diesel with good torque.
Economical Diesel Van for Long-Distance Families
With 81 kW the Mazda 5 CR diesel is no sprinter, but delivers decent torque for relaxed motorway runs. Road manners are predictable and stable — typical van behaviour. For families who prioritise consumption over driving pleasure.
Engine Weaknesses 7
The RF diesel is an interference engine. If the timing belt snaps, pistons and valves collide — the cylinder head must be replaced. Change interval: 80,000 km or 8 years.
Symptoms: Engine won't start after belt snap, no compression, metallic noises on start attempts
The solenoid valve beneath the injection pump leaks. Diesel seeps out and can attack coolant hoses and wiring looms. Diesel specialists replace only the valve rather than the entire pump.
Symptoms: Diesel smell in engine bay, visible fuel moisture beneath the injection pump, swollen coolant hoses
The Denso injection driver module (IDM, RF2A-18-701A) under the intake manifold develops earthing problems with age. Fault codes are often not set — difficult to diagnose.
Symptoms: Engine barely responds to throttle when cold, jerky acceleration below 1,500 rpm, normal behaviour above 2,500 rpm
The injector flame seals become porous and leak from around 120,000 km. Diesel mixture escapes and mixes with the engine oil, causing a sharp rise in oil consumption. A known production issue on the RF diesel engine.
Symptoms: Dark, heavily diluted engine oil; elevated oil consumption up to 1 litre/500 km; faint diesel smell at the engine.
The conical seating faces where the high-pressure fuel lines screw into each cylinder can develop leaks. Diesel smell after driving and persistently damp spots on the cylinder head are typical signs.
Symptoms: Strong diesel smell after shutdown; damp spots at line connections on the cylinder head; no visible leak when stationary.
The alternator of the RF diesel engine can fail from around 150,000 km due to bearing failure or regulator faults. The battery is no longer charged and the charge warning light illuminates.
Symptoms: Charge warning light on; battery discharges while driving; vehicle stalls.
The EGR valve carbons up and causes rattling noises and power loss. There are also wiring issues at the EGR electrics that promote temperature-dependent failures.
Symptoms: Rattling from the intake area, power loss especially after rain or cold start, impaired turbo response
Vehicle Weaknesses 8
The Mazda 5 CR is highly prone to rust: underside, door folds, tailgate and body panels show through-rust even at moderate mileage. A lift inspection is essential before purchase.
Central locking actuator motors in the sliding doors fail, especially after several years of operation. Door locks freeze in winter. Complete motor failure requires parts replacement.
The ball joint on the CR's control arm develops play with increasing mileage and is classified as a significant defect at MOT. Independent garages can replace just the ball joint; Mazda dealers only sell the complete control arm for around €400.
The AC compressor magnetic clutch on the CR fails and prevents the air conditioning from engaging. Often only the coil (magnetic ring) is defective and can be replaced for around €37 individually – instead of the full compressor for €800–1,000. Fault code B1261 (solar sensor) may appear.
Dampers and anti-roll bar rubbers wear early, especially on earlier model years. Rear dampers are particularly susceptible. Rattling from the suspension is an early warning sign.
The plastic tailgate develops cracks near the upper hinges, caused by stress from repeated opening and closing. A used replacement tailgate is cheaper than a repair.
The anti-roll bar bushings on the CR wear and develop up to 5 mm of play. This results in rattling over uneven surfaces, particularly annoying at low speed on cobblestones. The bushings are inexpensive and can be swapped on a lift in 30–45 minutes.
A faulty thermostat on the CR keeps the large coolant circuit permanently open, preventing the engine from reaching operating temperature and leaving the heater cold. The coolant temperature gauge remains well below the normal range. The thermostat is inexpensive; aftermarket parts cost under €40.