Mazda 6 GJ

The 2.2 SkyActiv-D is a powerful low-compression diesel — economical and rev-happy, but maintenance-intensive. The central issue is oil dilution: on short trips DPF regenerations are aborted, diesel gets into the oil and the level rises. The thinned, metal-laden oil accelerates a cascade — on early engines (up to 2013) the exhaust camshaft wears (a hardening defect) and abrasion particles then destroy the sequential turbo and the vacuum pump (recall R/2018/236). Injector seals (recall R/2018/289), EGR/intake carbon and DPF clogging add to it. Drive mostly long distances, change the correct oil with the ECU reset regularly and pick a 2014-on engine, and you get a strong, durable diesel.

• !! Camshaft Seized from 80,000 km

  Insufficient surface hardening of the exhaust camshaft leads to heavy wear with metal particles in the oil. Secondary damage to the vacuum pump and turbocharger is possible. Primarily affects build years 2012–2015.

  Symptoms: Warning 'Low oil pressure – engine damage possible', fault code P0056F, jerky gearbox, metal particles visible in oil on change.
  500–5,000 $
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• !! Severe Oil Dilution from Fuel Ingress from 30,000 km

  DPF regeneration injects fuel into the cylinder, which passes the piston and enters the oil. Dilution rates of up to 20–25% are possible. Increased engine wear and turbocharger bearing damage can follow.

  Symptoms: Oil level rises above MAX mark, fuel smell in oil, onboard computer shortens oil change interval, up to 20% diesel detectable in oil analysis.
  100–400 $
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• !! Sequential turbocharger fails from 120,000 km

  The 2.2 SkyActiv-D uses a two-stage sequential turbo (small high-pressure plus large low-pressure). It often fails as a consequence of camshaft wear — abrasion particles in the oil destroy the bearings — or from carbon/oil dilution. An expensive turbo-assembly replacement.

  Symptoms: Power loss under load, hesitation at 1,500–2,000 rpm, blue-black smoke, limp mode, whistling.
  1,500–3,000 $
  Ad Mazda 2.2 SkyActiv-D turbochargerSH-VPTS sequential turbo

+ 6 more engine weaknesses + vehicle weaknesses

The 2.0-litre SkyActiv-G is Mazda’s most-fitted petrol — a high-compression naturally aspirated direct-injection unit, economical and notably reliable. Its main weak point is the electronic coolant control valve, which sticks open and lets the engine run cold (code P0126, program SSP D8). Early build years occasionally had low oil pressure from a fouled oil-pump relief valve (P0524). The direct injection cokes the intake valves with mileage (walnut blasting is the fix), and the switchable hydraulic lash adjusters can tick when cold. On at least 95 octane with clean oil service the engine lasts a very long time.

• !! Low oil pressure — oil pump pressure relief valve from 80,000 km

  On early build years debris lodges on the oil-pump pressure relief valve and oil pressure drops (codes P0015/P0524). The fix is to replace the oil pump and strainer and clean the sump. Not to be confused with a low oil level.

  Symptoms: Oil pressure warning light illuminates, knocking noises from the engine, increased engine noise at low revs
  350–700 $
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• !! Defective coolant control valve (thermostat)

  The electronic coolant control valve (CCV) with its failsafe thermostat sticks open, so the engine never warms up (code P0126). Mazda issued program SSP D8 with a warranty extension; the permanent fix is the revised kit or a blanking plug plus a software update.

  Symptoms: Extended warm-up phase, blue coolant warning light, poor heater output at idle
  150–400 $
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• ! Carbon build-up on intake valves from 110,000 km

  Direct-injection carbon build-up on intake valves from crankcase breather oil mist. Typically occurs between 100,000–160,000 km. Walnut blasting is the only lasting solution.

  Symptoms: Rough cold start with misfire codes P0300–P0304, sluggish throttle response, increased fuel consumption
  185–800 $
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+ 3 more engine weaknesses + vehicle weaknesses

The 2.5-litre SkyActiv-G is the family’s big naturally aspirated direct-injection engine, strong and fundamentally long-lived. The most serious topic concerns the cylinder-deactivation variants (2018+): the cylinder head can crack at the rear and leak oil onto the exhaust manifold — an expensive failure. There is also the cylinder-deactivation software recall (NHTSA 19V-497, valve lash). Early build years have a leaking hydraulic belt tensioner, and the direct injection cokes the intake valves. A fuel-pump recall (21V-875) affects certain years. Without cylinder deactivation the 2.5 is a very solid engine.

• !! Cylinder head cracks (cylinder deactivation) — oil leak from 60,000 km

  On the cylinder-deactivation variants (2018+) the cylinder head can crack finely at the rear and leak oil onto the exhaust manifold — distinct from the 2.5 turbo coolant crack. No revised head design exists yet; the repair usually means engine-out.

  Symptoms: Smell of oil and smoke from the engine bay, oil patches, dropping oil level, eventually power loss.
  2,000–8,000 $
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• !! Recall: Cylinder Deactivation Valve Lash Adjuster

  Faulty PCM software mismanages the hydraulic valve lash adjuster when switching from cylinder deactivation to full power; the intake rocker arm can shift and contact internal parts — misfire, power loss, possible stall (NHTSA 19V-497). Remedy: free software update.

  Symptoms: Misfires, power loss, rough running when upshifting out of cylinder deactivation
  0–0 $
  Ad PCM update CX-5 KF 2.5 turboRocker arm intake valve SkyActiv-G 2.5T
• !! Fuel Pump Impeller Fracture

  Recall for 2019–2020 CX-5: the low-pressure fuel pump impeller can fail due to cracking. Mazda notified owners in November 2021. Engine stall possible.

  Symptoms: Engine won't start, power loss, irregular engine running, engine warning light
  300–800 $
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+ 3 more engine weaknesses + vehicle weaknesses