Mazda 626
2.5-litre KL-DE V6 with 24 valves. Refined six-cylinder with smooth power delivery.
V6 Gentleman
The silky V6 with manual gearbox turns the 626 into an underrated gentleman's express. Balanced and assured.
Engine Weaknesses 7
The distributor with integrated electronics fails under heat — the transistor gives out. Engine cuts out after roughly 14 km of driving but can be restarted. A known V6 affliction.
Symptoms: Engine cuts out while driving, spark very weak on a warm engine, difficult cold start
The thermostat no longer opens the large cooling circuit — a frequently reported problem among 626 V6 owners. Upper coolant hose is hot, lower one barely warm. Engine overheats quickly.
Symptoms: Coolant temperature rises unusually fast, lower coolant hose stays cold, temperature gauge in the red
At higher mileages the valve stem seals become porous. Oil passes from the cylinder head into the combustion chambers — typical when the car has been sitting and on overrun.
Symptoms: Blue smoke from the exhaust on cold start or after standing, faint oil smell, slowly dropping oil level
The gasket between the intake manifold and throttle body hardens and cracks over time. The engine draws in false air, causing rough running and an unstable idle.
Symptoms: Rough idle, engine stumbles at standstill, increased fuel consumption, occasional stalling
The lambda sensors of the KL-DE V6 age from around 100,000 km. Sluggish regulation leads to fault code P0421 (catalyst system efficiency below threshold). OEM sensor approx. €120, NGK replacement approx. €189, fitting approx. €300–500 total.
Symptoms: Check engine light on intermittently; fault code P0421 on OBD scan; measurable increase in fuel consumption; engine otherwise runs without issues.
The engine mounts of the KL-DE V6 wear from around 100,000 km. Cracked hydraulic mounts produce vibrations at idle and clunking on pull-away. A typical ageing issue on older Mazda models.
Symptoms: Vibrations felt at idle and when applying throttle; clunking or knocking on pull-away; engine visibly rocks when revved.
On the V6 KL-DE the valve cover gasket becomes porous from around 80,000 km, especially at the rubber rings around the spark plug bores. Oil leaking into the plug wells can cause misfires.
Symptoms: Oil traces on the cam cover; oil visible in the spark plug wells; occasional misfires when oil contaminates the plugs.
Vehicle Weaknesses 8
The left fuel tank on the 626 GF can corrode internally and develop leaks. Complete through-rust has been documented in isolated cases and requires a tank replacement.
Nearly all 626 GF show rust on the rear wheel arches (10 o'clock position on the wheel arch), door folds and tailgate. Poor factory sealing is the main cause.
Rear brake calipers corrode and seize, especially after prolonged parking with the handbrake applied. The handbrake cable rusts and the adjustment mechanism fails.
Control arm ball joints and rubber bushings on the GF wear significantly with age. Trailing arms can corrode at the wheel hub connection. All four control arms and both trailing arms should be replaced together, as the parts wear interdependently.
Wheel speed sensors at the rear axle fail frequently, triggering an ABS warning. Individual sensors are cheap; a faulty control unit can be expensive.
The AC condenser and dryer on the GF become leaky with age and lose refrigerant. Running with insufficient refrigerant risks total compressor failure. The condenser and dryer should be replaced together.
The steering torque sensor on the GF, which measures the required steering force and controls the power assistance, can fail and lead to heavy or inconsistently assisted steering. The sensor is integrated into the steering system and can be replaced separately.
The faux leather on the steering wheel and gear knob cracks and peels after a few years. The driver's seat bolster also shows cracking. A purely cosmetic issue with no safety implications.