Mazda 6
2.0-litre common-rail diesel in various development stages (RF4F, RF5C, RF7J). Solid everyday diesel with good torque.
Sensible Diesel Estate Without Sporting Ambitions
The 89 kW diesel in the Mazda 6 GG is a solid everyday engine with good torque for the estate. The chassis is well-tuned even with the diesel, but the package as a whole feels relaxed rather than sporty. A good choice for the pragmatist.
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 6
The Mazda 6 GG/GY up to 2006 has serious corrosion issues on sills, wheel arches, lower door edges and tailgate. Inadequate corrosion protection from the factory. Rust blisters appear after just a few years.
The rear brake calipers on the Mazda 6 GG are prone to corrosion on the handbrake mechanism and guide pins. As a known weakness of the model line, the calipers frequently need to be replaced.
Front wheel bearings on the Mazda 6 GG often fail below 80,000 km. A known problem of the first generation; substandard bearings were fitted from the factory in some cases.
Over-stiff strut top mounts are a known early issue on the Mazda 6 GG/GY before 2005. The bearing scrapes and creaks when steering. Significantly improved after the 2005/2006 facelift.
Brake discs on the Mazda 6 GG wear quickly and warp with normal use. Steering wheel judder under braking is a well-known Mazda issue across all generations.
The headlight levelling system on the Mazda 6 GG fails. The actuator motors or their control fails, which can result in an MOT defect.