Diagnostic: Black smoke on Opel - Causes and costs

Black smoke from the exhaust of an Opel (Corsa, Astra, Mokka, Crossland, Grandland) usually indicates over-fuelling (too much fuel relative to air) or a combustion problem. Depending on the engine (petrol or diesel), causes and costs differ.

Opel diesel (BlueHDi, Multijet)

On Opel diesel engines, black smoke is often linked to a blocked particulate filter (DPF) or a faulty injector. A saturated DPF can cause black smoke under acceleration. A leaking or misadjusted injector also produces black smoke. Other possible causes: turbo, lambda sensor, clogged EGR valve.

Opel petrol (PureTech, ECOTEC)

On Opel turbo petrol engines, black smoke can come from a turbo leak (oil), a faulty MAF sensor or an injection system that is poorly adjusted. Prolonged over-fuelling can damage the catalyst.

Indicative costs

• DPF clean / regeneration: about €80–200. DPF replacement: €800–1,800.
• Diesel injector: about €300–600 per injector. Turbo: €800–2,500 depending on engine.

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