Mitsubishi 4J10 Engine - Replacement Cost, Problems & CompatibilityProblems & Compatibility

A reconditioned 4J10 costs £1,200-£2,500+ supply-only, plus £480-£700 for fitting at a specialist Mitsubishi workshop. Used units start from £600, and full rebuilds range from £2,000-£3,500+. Prices vary significantly by whether the timing chain, piston rings, and MIVEC components have been replaced. A used engine without documented oil change history using the correct 5W-20/5W-30 oil is a gamble - avoid it. Reconditioned units with new timing chain and piston rings command a premium.

• A used engine without documented oil change history using the correct 5W-20/5W-30 oil is a gamble - avoid it.
• Reconditioned units with new timing chain and piston rings command a premium.

The most significant issues are oil consumption (caused by MIVEC system sensitivity and piston ring wear on higher-mileage engines), timing chain stretch (causing rattling on startup), and ignition coil failure (causing misfires and Check Engine Light). The MIVEC system is demanding on oil quality - using the wrong oil can lead to premature wear. Regular oil changes (every 8,000-10,000 miles) using the correct 5W-20 or 5W-30 oil are critical. Listen for timing chain rattle on cold starts - replace promptly if heard.

• Regular oil changes (every 8,000-10,000 miles) using the correct 5W-20 or 5W-30 oil are critical.
• Listen for timing chain rattle on cold starts - replace promptly if heard.

The 4J10 is fitted to the Mitsubishi ASX (2012+) and Mitsubishi Lancer (2012-2017) in the UK market, producing 139 hp. It replaced the older 4B10 across the compact and crossover ranges. The engine is available in the ASX 1.8 MIVEC and Lancer 1.8 MIVEC. Always confirm your engine code using the VIN or our reg-lookup tool.

• The engine is available in the ASX 1.8 MIVEC and Lancer 1.8 MIVEC.
• Always confirm your engine code using the VIN or our reg-lookup tool.

For most owners, a reconditioned unit offers the best balance - it includes new timing chain, piston rings, ignition coils, water pump, and a 12-24 month warranty. Used units are cheaper but carry risk of oil consumption and timing chain issues; full rebuilds are justified only if the original block is salvageable. Reconditioned from £1,200; used from £600; rebuilt from £2,000. A used engine without documented oil change history is a significant risk.

• Reconditioned from £1,200; used from £600; rebuilt from £2,000.
• A used engine without documented oil change history is a significant risk.

The engine code is stamped on a metal plate on the cylinder block (typically on the front or side of the engine), and appears on the V5C and in the VIN. The 4J10 is the SOHC MIVEC 1.8L from 2011 onward with next-generation MIVEC (continuous valve lift, duration and timing). The 4B10 is the older DOHC MIVEC 1.8L (2005-2012) that only varies valve timing. The 4J10 uses a simpler SOHC design with more advanced MIVEC control. Fitting the wrong engine variant can cause ECU and emissions compatibility issues.

• The 4J10 uses a simpler SOHC design with more advanced MIVEC control.
• Fitting the wrong engine variant can cause ECU and emissions compatibility issues.

The 4J10 is generally reliable when properly maintained, but is more sensitive to oil quality than the 4B10. The next-generation MIVEC system demands regular oil changes using the correct 5W-20 or 5W-30 oil. The 4J10 is more fuel-efficient and lighter than the 4B10, with less internal friction. However, the MIVEC system can become compromised if oil changes are neglected. Regular servicing and using the correct oil are critical to longevity. Many specialists recommend proactive timing chain replacement at 80,000-100,000 miles.

• Regular servicing and using the correct oil are critical to longevity.
• Many specialists recommend proactive timing chain replacement at 80,000-100,000 miles.