Nissan Sentra B18

2.0L direct injection with timing chain. Fundamentally solid, but injectors can foul.

• !! Timing chain elongates at high mileage from 130,000 km

  The MR20DD timing chain can elongate from around 130,000 km causing rattling noises. Low oil level significantly accelerates wear. As the MR20DD is an interference engine, a broken chain causes severe engine damage.

  Symptoms: Rattling on cold start, metallic chattering on load changes, rough running
  700–1,800 $
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• !! Cylinder head cracks — sensitive aluminum from 120,000 km

  The MR20DD aluminum cylinder head is sensitive to overheating and over-tightened spark plugs. Even modest overtorquing during a plug change can crack the coolant passages around the plug bores. Coolant loss without any visible external leak is the first warning sign.

  Symptoms: Dropping coolant level with no visible external leak, overheating indicator, white smoke from exhaust, coolant smell in engine bay
  1,500–4,000 $
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• !! Intake valves carbon up (direct injection) from 80,000 km

  As a pure direct injection engine the MR20DD does not wash the intake valves with fuel. Carbon deposits build from around 80,000 km, causing rough idle, power loss, and increased consumption.

  Symptoms: Rough idle, hesitation on pull-away, increased fuel consumption, power loss on a cold engine
  300–700 $
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+ 2 more engine weaknesses + vehicle weaknesses