Mazda 6 2.0 GH

The Mazda 6 GH uses an all-electric power steering system with an integrated torque sensor in the steering rack. A known fault causes the sensor to drift out of calibration, resulting in light steering in one direction and heavy in the other. This can develop gradually and rarely triggers a fault code, making it easy to miss during a quick test drive. A full steering rack replacement costs around €1,200-1,500, though specialist remanufacturers can rebuild the rack for €400-600. The issue tends to appear after 80,000-120,000 km and affects all GH models regardless of engine.

The MZR 2.0 engine has a known thermostat weakness, typically failing around 80,000-100,000 km. A thermostat stuck open causes the engine to take too long to reach operating temperature, resulting in poor fuel economy and reduced cabin heating. A thermostat stuck closed is more dangerous, leading to overheating. The part itself costs around €40-60, with 1-2 hours of labour. Total repair cost is typically €200-400 at an independent shop. While not catastrophic, ignoring a stuck-closed thermostat can lead to head gasket damage.

A loud ticking noise from the top of the engine on cold start is commonly reported on higher-mileage MZR engines. The hydraulic valve lash adjusters (lifters) stick due to oil sludge buildup, particularly when oil change intervals have been extended. The ticking usually subsides within 30-60 seconds as oil pressure builds. In mild cases, switching to a quality full-synthetic oil and shorter change intervals can resolve it. If the lifters are physically worn, replacement costs €400-1,200 depending on how many need replacing. Prevention is straightforward: stick to 10,000-15,000 km oil change intervals with the correct 5W-30 specification.

Water ingress through worn weatherstrips can reach the door lock actuators, causing intermittent failures. Symptoms include the alarm going off randomly (especially overnight or after rain), doors not locking or unlocking properly, and interior lights staying on with doors closed. The rear door actuators are most commonly affected. A replacement actuator costs around €60-100 for the part, with 1-2 hours of labour. Replacing weatherstrips at the same time is recommended to prevent recurrence. Total repair is typically €150-400 per door.

The MZR LF-DE engine can develop increased oil consumption beyond 150,000 km, primarily due to hardening valve stem seals. Consumption of 0.5-1.0 litre per 5,000 km is considered within Mazda's acceptable range, but some engines consume more. If caught early, regular top-ups (€100-200/year in oil) is the cheapest approach. A full valve stem seal replacement requires cylinder head work and costs €1,500-2,000. Most owners manage this with monitoring and top-ups rather than a full repair. The issue is more pronounced on engines that ran extended oil change intervals.

Mazda addressed the severe rust issues of the first-generation 6 (GG) for the GH, but the car is not immune. Surface corrosion on the front subframe and rear suspension components is commonly found on cars from salt-road regions. Serious structural corrosion is less common than on the GG but does occur, particularly on the sills, inner rear arches, and subframe mounting points. Mazda extended the perforation warranty to 12 years from 2006 onwards. Repair costs vary widely: surface treatment and anti-corrosion wax is €300-500, while structural welding repairs can reach €1,500-2,000. Cars from southern European or Scandinavian (garage-kept) markets tend to be in better condition.

One or both bolts at the rear exhaust flange are prone to corroding and breaking, particularly on cars in wet or salty climates. The result is an exhaust leak with noticeably louder exhaust noise. The repair is relatively straightforward: drilling out the broken bolt, replacing with a new bolt and gasket, and applying anti-seize compound. Total cost is typically €100-300 at an independent shop. While not a safety issue, it will cause an MOT/TUV failure if the leak is significant.