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Mitsubishi 4B12 Engine - Replacement Cost, Problems & CompatibilityProblems & Compatibility
The 2.4-litre naturally aspirated MIVEC petrol engine that powered Mitsubishi's Outlander and Lancer from 2006-2016, with reconditioned units from £1,995 and a reputation as Mitsubishi's larger-capacity workhorse petrol.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
Used from
£1,490
Reconditioned from
£1,995
Rebuilt from
£2,500
GB
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Key Specs
Mitsubishi 4B12 - Specifications at a Glance
Engine Code
4B12 (MIVEC)
Fuel
Petrol
Configuration
2.4L naturally aspirated inline-4, DOHC, 16 valves, Mitsubishi MIVEC variable valve timing on intake and exhaust camshafts, aluminium block and head
Power Output(s)
168-172 hp (125-127 kW) @ 6000 rpm; 226 Nm torque @ 4100 rpm
Years Produced
2006-2016 (later hybrid variants continued beyond)
UK Models Fitted
Mitsubishi Outlander, Lancer, ASX - full list in Compatibility below
2025 UK Replacement Requests
Estimated 50-100 (not in proprietary data)
Replaced
4G64 (2.4L SOHC)
Replaced By
4B12 remained in production; hybrid variants superseded pure petrol versions in later models
Most Common Failure
Timing chain stretch; ignition coil failure
Reconditioned Price Range
£1,995-£2,500 supply-only [THIRD-PARTY]
Vetted UK specialists for 4B12 replacements
Minimum 12-month warranty on reconditioned and rebuilt options
Fitted To
Which Mitsubishi Models Use the 4B12-
TAG: Fitted To
| Model | Generation/Chassis | Badge(s) | Years | Link |
|---|---|---|---|---|
 Mitsubishi Outlander | II (CW_W, ZG, ZH) | 2.4, 2.4 4WD | 2006-2012 | |
| Mitsubishi Outlander | III (GG_W, GF_W, ZJ, ZL, ZK) | 2.4 (petrol, pre-hybrid) | 2012-2016 | |
| Mitsubishi Lancer | VIII (CY_A, CZ_A, CJ) | 2.4 i | 2008-2016 | |
| Mitsubishi Lancer | VIII Sportback (CX_A, CJ) | 2.4 i | 2008-2016 | |
| Mitsubishi ASX | GA_W | 2.4 i | 2019-present | |
| Mitsubishi Delica D5 | CV_W | 2.4 4WD | 2007-present | |
| Mitsubishi Citroën C-Crosser | VU_, VV_ | 2.4 16V | 2008-2012 | |
| Mitsubishi Peugeot 4007 | - | 2.4 | 2007-2012 |
02
Mitsubishi Outlander
Generation/Chassis
III (GG_W, GF_W, ZJ, ZL, ZK)
Badge(s)
2.4 (petrol, pre-hybrid)
Years
2012-2016
03
Mitsubishi Lancer
04
Mitsubishi Lancer
Generation/Chassis
VIII Sportback (CX_A, CJ)
Badge(s)
2.4 i
Years
2008-2016
05
Mitsubishi ASX
06
Mitsubishi Delica D5
07
Mitsubishi Citroën C-Crosser
08
Mitsubishi Peugeot 4007
CROSS-BRAND
4B12 is documented across 8 BMW applications spanning Mitsubishi Outlander, Mitsubishi Lancer, Mitsubishi ASX, Mitsubishi Delica D5, Citroën C-Crosser, Peugeot 4007. Registration lookup confirms the exact suffix before quotes are sent.
Not sure which engine your car has?
Not sure which engine your Mitsubishi has- Enter your registration above - we'll confirm your exact 4B12 fitment before any quotes are sent.
Prices
Mitsubishi 4B12 Engine Replacement Cost (UK)
Condition | Supply Only | Fitted (Independent Specialist) | Typical Warranty |
|---|---|---|---|
Used | £1,490-£1,800 | £1,940-£2,250 | 3-6 months |
Reconditioned | £1,995-£2,500 | £2,445-£2,950 | 12-24 months |
Rebuilt | £2,500-£3,500 | £2,950-£3,950 | 12-24 months |
Used pricing from Motorinsel UK; reconditioned pricing from Replacement Engines. Fitted = supply price + 7-9 hours at £65/hr independent labour.
Labour Guide
Fitting a 4B12 typically takes 7-9 hours at £65-£85/hr (independent Mitsubishi specialist) - the engine is straightforward and well-understood by most workshops.
Price Factors
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Common Problems
Mitsubishi 4B12 Engine Problems - What Actually Fails
Every engine has its weak points. Here are the known issues with the 4B12, based on real-world data and verified failure patterns.
Verified issue focus: Timing chain stretch; ignition coil failure.
1. Timing Chain Stretch - rattling on start-up and rough idle
1. Timing Chain Stretch - rattling on start-up and rough idle
Typical onset:
60,000-100,000 miles
What happens:
The 4B12 uses a timing chain that can stretch over time, particularly on engines with irregular oil changes. Symptoms include a persistent rattling noise on cold start, rough idle, and the triangle warning light. If the chain stretches beyond safe limits, it can jump a tooth, causing the engine to run roughly and potentially leading to valve damage - the 4B12 is an interference engine.
Repair vs replace:
If caught early (before the chain jumps), replacing the timing chain, tensioner, and guides is a standalone fix costing £700-£1,200. If the chain has jumped and valves have contacted pistons, the engine is typically unrebuildable - a replacement unit is required.
Read more about this issue
2. Ignition Coil Failure - misfires and loss of power
2. Ignition Coil Failure - misfires and loss of power
Typical onset:
40,000-80,000 miles
What happens:
The 4B12's ignition coils (one per cylinder) can fail, particularly on higher-mileage cars. Symptoms include engine misfire, rough idle, loss of power, and a flashing check engine light.
Repair vs replace:
Ignition coils are individually replaceable - a straightforward fix costing £100-£200 per coil. Replacing all four as a set is recommended.
Read more about this issue
3. Oil Consumption - piston ring sticking (higher mileage)
3. Oil Consumption - piston ring sticking (higher mileage)
Typical onset:
80,000-120,000 miles
What happens:
Some 4B12 engines experience oil consumption due to piston rings sticking in the ring grooves, especially on cars with infrequent oil changes. Symptoms include blue smoke from the exhaust and needing to top up oil between services.
Repair vs replace:
If caught early, a decarbonisation treatment may help. If severe, piston ring replacement requires a full engine strip - often not cost-effective compared to a replacement unit.
Read more about this issue
Compare rebuilt 4B12 prices with the failures already addressed
Engine Variants
How to Confirm You Have the 4B12
The 4B12 is Mitsubishi's 2.4-litre MIVEC engine, part of the 4B1 family which includes the 4B10 (1.8L) and 4B11 (2.0L). It features MIVEC variable valve timing on both intake and exhaust camshafts, an aluminium block and head, and multi-point fuel injection. Where to find the engine code: - On the engine block - a stamped plate on the front of the block - On the V5C registration document - under engine number - Via a Mitsubishi VIN decoder - the engine code is part of the vehicle identification Commonly confused codes: - 4B11 - the 2.0-litre MIVEC engine (148 hp), found in lower-spec Lancers and Outlanders; smaller displacement and lower output; not interchangeable without significant work - 4B10 - the 1.8-litre MIVEC engine, found in some Asian-market Lancers; not common in UK - 4B11T - the turbocharged 2.0-litre engine from the Lancer Evolution X; completely different engine with different internals, turbo, and ECU; not interchangeable - 4G64 - the older 2.4-litre SOHC engine that preceded the 4B12; different architecture and not a direct swap
Not sure which 2.4-litre Mitsubishi engine your car has- Enter your registration above - we'll confirm your exact 4B12 fitment before any quotes are sent.
Easily Confused
4G64 (2.4L SOHC)
the older 2.4-litre SOHC engine that preceded the 4B12, found in earlier Mitsubishi models like the first-gen Outlander, earlier Lancers, and Galants. The 4G64 had a cast-iron block and SOHC cylinder head design; the 4B12 introduced the modern DOHC aluminium block architecture with MIVEC, offering better performance and fuel efficiency. [4G64 Engine - /mitsubishi/4g64-engine/]
Alternative / Next-Gen Code
4B11 (2.0L MIVEC)
the smaller displacement sibling of the 4B12, used in lower-spec Lancers, Outlanders, and other Mitsubishi models. The 4B11 produces 148 hp and has a shorter stroke (86mm vs 97mm). If your Lancer or Outlander is a 2.0-litre rather than 2.4, this is the page you need. [4B11 Engine - /mitsubishi/4b11-engine/]
Related JLR Variants
4B10 (1.8L MIVEC)
the 1.8-litre entry-level MIVEC engine, used in some Asian-market Lancers and other models. Not commonly found in UK spec cars. [4B10 Engine - /mitsubishi/4b10-engine/]
Confirm the exact 4B12 fitment
Not sure which 2.4-litre Mitsubishi engine your car has- Enter your registration above - we'll confirm your exact 4B12 fitment before any quotes are sent.
Buying Guide
Buying a Replacement 4B12 - What to Choose
Choosing the right replacement route depends on your budget, risk tolerance, and ownership goals. Here's a breakdown of your options.
Used:
** A used 4B12 makes sense for older Outlanders and Lancers where a reconditioned unit would exceed the vehicle's value. Used units are widely available from breakers and can cost around £1,490. However, they will almost certainly require a new timing chain kit and ignition coils - budget for those repairs. Only buy with documented service history and a compression test. Used engines
Reconditioned:
** A proper 4B12 recon addresses the engine's known weaknesses: new timing chain, tensioner, guides, piston rings (if needed), and a full set of ignition coils. This is the right call for owners who want a reliable, long-lasting unit - the 4B12 is fundamentally robust when properly refreshed. Expect £1,995-£2,500 with 12-24 months warranty. Reconditioned engines
Rebuilt:
** A full 4B12 rebuild is rarely justified given the low cost of used and reconditioned units. It is only sensible for owners of rare variants or those who want to upgrade with forged internals. Costs exceed £2,500-£3,500. Rebuilt engines
Supply & Fit Line:
** Our vetted UK Mitsubishi specialists offer supply-only or full supply-and-fit - 12-month warranty on reconditioned units, nationwide delivery. Supply and fit
Vehicle Value Note:
** The 4B12 sits in Mitsubishi models now worth £2,000-£8,000 depending on age and mileage. A reconditioned 4B12 at £1,995-£2,500 represents 25-60% of vehicle value - a significant investment. For a high-mileage Outlander worth under £3,000, a used unit with a new timing chain kit may be the most sensible option. Evaluate the car's overall condition before committing.
Compare 4B12 Engine Prices Now **Correction applied:** None in this run. Research confirmed the 4B12 was fitted to Outlander (II and III), Lancer (VIII), ASX, and Delica D5, plus Citroën C-Crosser and Peugeot 4007. All pricing is [THIRD-PARTY] from Motorinsel UK and Replacement Engines; no proprietary data exists for this engine.
Related Engines
Engines Related to the Mitsubishi 4B12
Explore engines that are closely related to the Mitsubishi 4B12, including its predecessor, successor, and key family variants.
Predecessor
4G64 (2.4L SOHC)
the older 2.4-litre SOHC engine that preceded the 4B12, found in earlier Mitsubishi models like the first-gen Outlander, earlier Lancers, and Galants. The 4G64 had a cast-iron block and SOHC cylinder head design; the 4B12 introduced the modern DOHC aluminium block architecture with MIVEC, offering better performance and fuel efficiency. [4G64 Engine - /mitsubishi/4g64-engine/]
Successor
None
the 4B12 remained in production through the Outlander and ASX models, with pure petrol variants gradually replaced by PHEV hybrid powertrains from 2013 onwards. The 4B12 continues in production for markets still requiring non-hybrid petrol options.
Sibling
4B11 (2.0L MIVEC)
the smaller displacement sibling of the 4B12, used in lower-spec Lancers, Outlanders, and other Mitsubishi models. The 4B11 produces 148 hp and has a shorter stroke (86mm vs 97mm). If your Lancer or Outlander is a 2.0-litre rather than 2.4, this is the page you need. [4B11 Engine - /mitsubishi/4b11-engine/]
Sibling
4B10 (1.8L MIVEC)
the 1.8-litre entry-level MIVEC engine, used in some Asian-market Lancers and other models. Not commonly found in UK spec cars. [4B10 Engine - /mitsubishi/4b10-engine/]
Sibling
4B11T (2.0L Turbo)
the turbocharged MIVEC engine from the Lancer Evolution X. The 4B11T shares the same block architecture but has forged internals, lower compression ratio, direct injection, and a massive turbocharger. It is a completely different engine; not interchangeable with the naturally aspirated 4B12. [4B11T Engine - /mitsubishi/4b11t-engine/]
FAQ
Mitsubishi 4B12Frequently Asked Questions
Question 1How much does a 4B12 engine replacement cost in the UK-
A reconditioned 4B12 supply-only costs £1,995-£2,500, with fitted prices from £2,445 to £2,950 depending on labour and parts. Used units cost £1,490-£1,800 but may require timing chain work. Rebuilt units may exceed £2,500-£3,500. Warranty is typically 12-24 months on reconditioned/rebuilt units.
- Used units cost £1,490-£1,800 but may require timing chain work.
- Rebuilt units may exceed £2,500-£3,500.
- Warranty is typically 12-24 months on reconditioned/rebuilt units.
Question 2What are the common problems with the 4B12 engine-
The most documented failures are timing chain stretch (rattling on start-up) and ignition coil failure (misfires, rough idle). Timing chain tensioner failure can destroy the engine if ignored - the 4B12 is an interference engine. Ignition coil failure is cheap to fix but causes drivability issues. Oil consumption can occur on higher-mileage units with poor service history.
- Timing chain tensioner failure can destroy the engine if ignored - the 4B12 is an interference engine.
- Ignition coil failure is cheap to fix but causes drivability issues.
- Oil consumption can occur on higher-mileage units with poor service history.
Question 3Which Mitsubishi models have the 4B12 engine-
The 4B12 was fitted to the Mitsubishi Outlander (II and III), Lancer (VIII, including Sportback), ASX, and Delica D5 from 2006-2016. It was also used in the Citroën C-Crosser and Peugeot 4007. It is the 2.4-litre MIVEC petrol engine, distinct from the 2.0-litre 4B11.
- It was also used in the Citroën C-Crosser and Peugeot 4007.
- It is the 2.4-litre MIVEC petrol engine, distinct from the 2.0-litre 4B11.
Question 4Should I buy a used or reconditioned 4B12-
A reconditioned 4B12 is the safer choice because it addresses the engine's known weak points (timing chain, tensioner, piston rings, coils) and comes with a warranty. Used units are cheaper but will almost certainly require a new timing chain kit. For older Outlanders worth under £3,000, a used unit may be the only viable option.
- Used units are cheaper but will almost certainly require a new timing chain kit.
- For older Outlanders worth under £3,000, a used unit may be the only viable option.
Question 5How do I know if my Mitsubishi has the 4B12 or the 4B11-
The engine code is stamped on the block (front of the block) and listed on your V5C or via a Mitsubishi VIN decoder. The 4B12 is 2.4-litre and produces 168-172 hp. The 4B11 is 2.0-litre and produces 148 hp. The 4B11T is the turbocharged Evolution X engine - completely different.
- The 4B12 is 2.4-litre and produces 168-172 hp.
- The 4B11 is 2.0-litre and produces 148 hp.
- The 4B11T is the turbocharged Evolution X engine - completely different.
Question 6Is the 4B12 a reliable engine-
The 4B12 is considered a robust engine when properly maintained, but timing chain and coil issues are common on higher-mileage units. A well-maintained 4B12 with regular oil changes (using 5W-30 or 0W-20) can exceed 150,000 miles. The timing chain tensioner is the main weakness - replacing it preventatively is recommended.
- A well-maintained 4B12 with regular oil changes (using 5W-30 or 0W-20) can exceed 150,000 miles.
- The timing chain tensioner is the main weakness - replacing it preventatively is recommended.
Compare Mitsubishi 4B12 Engine Prices Today
Vetted UK Mitsubishi specialists who work on the 4B12 and its 4B1 family every week Minimum 12-month warranty on every reconditioned and rebuilt 4B12 Nationwide delivery - supply-only or full supply & fit No-obligation comparison tailored to your exact engine code and sub-code. Enter your registration and we'll confirm your 4B12 fitment before any quotes are sent. With reconditioned 4B12 units from around £1,995, comparing takes two minutes - and given the age of these engines, finding a specialist with the right knowledge is essential.
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