Mitsubishi Eclipse Cross: Excessive Engine Oil Consumption — 4B40 1.5T Turbo

Early-production 4B40 engines (predominantly 2018–2020) exhibit abnormally high oil consumption, with owners reporting up to 1 litre per 5,000 km or worse under normal driving. The root cause involves piston oil ring wear and turbocharger oil seal deterioration that allows oil to be drawn into the combustion chamber and exhaust, eventually fouling the catalytic converter and oxygen sensors. Mitsubishi dealers have acknowledged the issue on a case-by-case basis but no formal recall has been issued; post-warranty failures are common.

• Oil level drops noticeably between scheduled service intervals without visible external leak
• Blue or grey exhaust smoke on cold start or hard acceleration
• Oily residue inside intercooler pipes or air intake hoses
• Catalytic converter overheating smell or oxygen sensor fault codes
• Oil consumption exceeding 1 litre per 5,000 km

1. 1

   Check the dipstick with the engine cold before purchase and note the oil level precisely.

2. 2

   Ask for service records showing oil top-up history.

3. 3

   Inspect the air filter housing and intercooler pipes for an oily residue film indicating blowby.

4. 4

   Look for blue smoke from the exhaust on a cold start or under acceleration.

5. 5

   Check for a fouled or sooty catalytic converter smell.

Parts involved: Turbocharger.

$300 to $6,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Have you ever needed to top up oil between scheduled services, and by how much?”
• “Has the dealership carried out any engine inspection or replacement under warranty for oil consumption?”
• “Are there any service records showing unusually short oil-change intervals or added oil quantities?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.