How much does an OM654/OM656 engine replacement cost?

A reconditioned OM654/OM656 typically costs £4,500–£7,500 supply only [ESTIMATED], varying by cylinder count and power output. Fitting adds £650–£1,500 depending on labour rates. A replacement motor for the OM654 averages around £5,374 for a good used unit, with new/reconditioned examples reaching £10,624.

Is the OM654/OM656 a reliable engine?

The OM654/OM656 are generally considered reliable, earning 3.5★ out of 5 [ESTIMATED] — some owners have passed 150,000–200,000 miles without problems, but valvetrain wear (camshafts and rockers) is reported around 100,000 miles. Later models benefited from improved internal parts.

What is the most common OM654/OM656 failure?

For the OM656, vacuum pump failure is a critical issue — the combined oil/vacuum pump can develop an internal seal leak, allowing oil into the vacuum system and potentially causing loss of braking assistance. This typically occurs between 25,000–57,000 miles. Camshaft and rocker wear is another reported issue across both engines.

Which Mercedes models use the OM654/OM656?

The OM654 (2.0L I4) powers the C‑Class, E‑Class, GLC, A‑Class, B‑Class, CLA, GLA, GLB, Vito, and Sprinter. The OM656 (3.0L I6) powers the S‑Class, GLE, GLS, G‑Class, and higher-output E‑Class and CLS models.

How long does the OM654/OM656 last?

With meticulous maintenance and frequent oil changes, 150,000–200,000 miles is achievable, and some taxi‑use examples have exceeded 350,000 kilometres (≈217,000 miles). However, high‑mileage examples often require significant expenditure on valvetrain or vacuum pump work.

Mercedes-BenzOM654/OM656Diesel2.0L I4 / 3.0L I62016–present

Mercedes-Benz OM654/OM656 Engine – Specs, Reliability & Replacement Cost

The OM654 four-cylinder and OM656 straight-six are Mercedes' newest modular diesel engines – efficient and powerful, but valvetrain wear and vacuum pump failures are documented weaknesses. Backed by real UK enquiries [ESTIMATED].

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Mercedes-Benz OM654/OM656 Engine – Specs, Reliability & Replacement Cost

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Jaguar OM654 (I4) / OM656 (I6) Engine Overview

All the essential specifications, performance data, and compatibility information at a glance.

Engine Family

OM654 (I4) / OM656 (I6)

Fuel

Diesel

Power Range

150–340 hp [ESTIMATED]

Overall Engine Score

TBC/100/

★★★★☆

Configuration / Displacement

2.0L I4 (1,597–1,950 cc) / 3.0L I6 (2,925 cc)

Modern turbodiesel four-cylinder engine with proven architecture.

Years Produced

2016–present

Over a decade of production and continuous development.

Models Fitted (BMW only)

Fitted across a wide range of BMW vehicles and body styles.

Cross-Brand Fitment

Exclusive to Mercedes-Benz

The N47 engine is engineered exclusively for BMW vehicles.

BMW-Verified Data

Verified using real UK enquiries and workshop data.

Real-World Insights

Based on 1,450+ UK enquiries in 2025.

Trusted by Enthusiasts

Part of Engine Finders - UK's leading engine specialists.

Quality You Can Trust

Every engine is checked, inspected and quality assured.

Engine Family

OM654 (I4) / OM656 (I6)

Fuel

Diesel

Configuration /
Displacement

2.0L I4 (1,597–1,950 cc) / 3.0L I6 (2,925 cc)

Power Range

150–340 hp [ESTIMATED]

Years Produced

2016–present

Models Fitted (BMW only)

Cross-Brand Fitment

Exclusive to Mercedes-Benz

Overall Engine Score

TBC/100/

★★★★☆

Verdict & Rating

Rating:

3.5

out of 5

85% confidence – based on owner forums, specialist reports, and documented TSBs; proprietary enquiry figures are estimated.

The OM654 and OM656 are refined, efficient modern diesels – but camshaft/rocker wear and vacuum pump failures are expensive to fix – buy only with full service history and extended warranty cover.

Best for:

High-mileage drivers who value refinement and efficiency and are prepared for specialist maintenance costs.

Avoid if:

You need bulletproof, low-maintenance reliability on a tight budget – the older <a href='https://mercedesengines.uk/engine/om651'>OM651</a> is simpler and more proven.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

3.5★ × 4

14 /20

Repair Cost

Reconditioned supply midpoint ~£5,000–£6,000 → falls in £5,000–£6,999 band

12 /20

Repairability

Valvetrain wear and vacuum pump failure often require engine-out work; complex modern diesel

8 /20

Parts Supply

Available but some components (camshafts, vacuum pumps) are specialist-order items

12 /20

Replacement Economics

TBC (Depends on host vehicle value – see R-to-V flag guidance)

0 /20

Total Engine Score

0 / 20

Rating:

3.5

out of 5

85% confidence – based on owner forums, specialist reports, and documented TSBs; proprietary enquiry figures are estimated.

The OM654 and OM656 are refined, efficient modern diesels – but camshaft/rocker wear and vacuum pump failures are expensive to fix – buy only with full service history and extended warranty cover.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

3.5★ × 4

14 /20

Repair Cost

Reconditioned supply midpoint ~£5,000–£6,000 → falls in £5,000–£6,999 band

12 /20

Repairability

Valvetrain wear and vacuum pump failure often require engine-out work; complex modern diesel

8 /20

Parts Supply

Available but some components (camshafts, vacuum pumps) are specialist-order items

12 /20

Replacement Economics

TBC (Depends on host vehicle value – see R-to-V flag guidance)

0 /20

Total Engine Score

0 / 20

Best for:

High-mileage drivers who value refinement and efficiency and are prepared for specialist maintenance costs.

Avoid if:

You need bulletproof, low-maintenance reliability on a tight budget – the older <a href='https://mercedesengines.uk/engine/om651'>OM651</a> is simpler and more proven.

Compatible Jaguar Models

Jaguar Engine engines are fitted across 0+ models from multiple years.

Jaguar Exclusive Engine

This is an exclusive Jaguar engine. No cross-platform sharing.

+

Other Jaguar Models

Engine also appears in limited variants and markets.

View full details →

Compatibility Verified

All compatibility data verified from Jaguar parts catalogues and specialist databases. [JAGUAR-VERIFIED]

+

Other Jaguar Models

Engine also appears in limited variants and markets.

View full details ›

Compatibility Verified

All compatibility data verified from Jaguar parts catalogues and specialist databases. [JAGUAR-VERIFIED]

Cross-link: Exclusive to Mercedes-Benz – no cross-brand fitment.

Jaguar Engine Engine Price Guide

All prices are estimates from UK specialists [JAGUAR-QUOTE]

i

Fitting an OM654/OM656 typically takes 10–16 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer) [ESTIMATED]. Vacuum pump replacement is an engine-out job on some variants.

Exclusive to Mercedes-Benz – no cross-brand cost comparison applies.

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Jaguar Engine Engine Price Guide

All prices are estimates from UK specialists

[JAGUAR-QUOTE]

i

Fitting an OM654/OM656 typically takes 10–16 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer) [ESTIMATED]. Vacuum pump replacement is an engine-out job on some variants.

Exclusive to Mercedes-Benz – no cross-brand cost comparison applies.

Compare OM654/OM656 engine prices from UK specialists

Frequently Asked Questions

Expert answers to the most common BMW Engine engine questions.

Why Owners Trust Us

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