How much does an OM621/OM622/OM626 engine replacement cost?

A reconditioned OM-series diesel typically costs £1,200–£2,500 supply only [ESTIMATED], varying by displacement and variant. Fitting adds £300–£600 depending on labour rates and vehicle model.

Is the OM621/OM622/OM626 a reliable engine?

Yes — these engines rate 4.5★ out of 5 based on decades of owner data [MB-INTERVIEW]. They are legendary for their extreme longevity, with many examples exceeding 300,000 miles when maintained.

What is the most common OM621/OM622/OM626 failure?

Injection pump wear is the most common issue, causing starting problems. Glow plug failure and fuel system air leaks are also frequent on older examples.

Which Mercedes models use the OM621/OM622/OM626?

These engines power the W110 (190D), W114/W115 (Stroke 8, 200D/220D/240D), W123 (200D/220D/240D), and W201 (190D, 190D 2.5) — classic Mercedes from 1958 to 1988.

How long does the OM621/OM622/OM626 last?

With simple maintenance, these engines routinely exceed 300,000 miles. Many specialists report examples at 500,000+ with original internals — one of the most durable engines ever built [MB-INTERVIEW].

Mercedes-BenzOM621/OM622/OM626Diesel2.0–2.4L I41958–1988

Mercedes-Benz OM621/OM622/OM626 Engine – Specs, Reliability & Replacement Cost

The Mercedes OM621/OM622/OM626 are legendary pre-chamber diesels – known for extreme longevity and simplicity. Backed by UK specialist consensus and classic car community insight [MB-INTERVIEW].

Compare OM621/OM622/OM626 Engine Prices

Mercedes-Benz OM621/OM622/OM626 Engine – Specs, Reliability & Replacement Cost

Compare OM621/OM622/OM626 Engine Prices

Specialist Verified
Classic Models
/100
Engine
Score
Part of Engine Finders

Jaguar OM621 / OM622 / OM626 Engine Overview

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

Engine Family

OM621 / OM622 / OM626

Fuel

Diesel

Power Range

55–90 hp (variants)

Overall Engine Score

TBC/100/

★★★★☆

Configuration / Displacement

2.0–2.4L inline-4 pre-chamber diesel

Modern turbodiesel four-cylinder engine with proven architecture.

Years Produced

1958–1988 (OM621: 1958–1976; OM622: 1973–1976; OM626: 1976–1988)

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

OM621 / OM622 / OM626

Fuel

Diesel

Configuration /
Displacement

2.0–2.4L inline-4 pre-chamber diesel

Power Range

55–90 hp (variants)

Years Produced

1958–1988 (OM621: 1958–1976; OM622: 1973–1976; OM626: 1976–1988)

Models Fitted (BMW only)

Cross-Brand Fitment

Exclusive to Mercedes-Benz

Overall Engine Score

TBC/100/

★★★★☆

Verdict & Rating

Rating:

4.5

out of 5

90% confidence – based on decades of owner data and specialist knowledge of these classic diesel engines.

The OM621/OM622/OM626 are legendary for their endurance and simplicity – injection pump and glow plug issues are common but easy to resolve – buy on rust-free shell, not engine condition.

Best for:

Classic Mercedes enthusiasts wanting bulletproof mechanical diesels.

Avoid if:

You want modern power, refinement, or a fast diesel.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

Star rating (4.5★) × 4 = 18

18 /20

Repair Cost

Reconditioned midpoint: under £3,000 → 20

20 /20

Repairability

Most failures are cheap, well-understood repairs (injector pumps, glow plugs)

20 /20

Parts Supply

Good availability through classic specialists, but some parts are becoming scarce

16 /20

Replacement Economics

Reconditioned cost well under 30% of classic vehicle values

20 /20

Total Engine Score

94 / 100

Rating:

4.5

out of 5

90% confidence – based on decades of owner data and specialist knowledge of these classic diesel engines.

The OM621/OM622/OM626 are legendary for their endurance and simplicity – injection pump and glow plug issues are common but easy to resolve – buy on rust-free shell, not engine condition.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

Star rating (4.5★) × 4 = 18

18 /20

Repair Cost

Reconditioned midpoint: under £3,000 → 20

20 /20

Repairability

Most failures are cheap, well-understood repairs (injector pumps, glow plugs)

20 /20

Parts Supply

Good availability through classic specialists, but some parts are becoming scarce

16 /20

Replacement Economics

Reconditioned cost well under 30% of classic vehicle values

20 /20

Total Engine Score

94 / 100

Best for:

Classic Mercedes enthusiasts wanting bulletproof mechanical diesels.

Avoid if:

You want modern power, refinement, or a fast diesel.

Compatible Jaguar Models

Jaguar Engine engines are fitted across 5+ models from 1958–1988.

Jaguar Exclusive Engine

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

1958

30 Years of Production

1988

190D

W110 (Fintail) · W201

190D

1958–19881 Variants →

200D

W110 (Fintail) · W115 (Stroke 8) · W123

200D

1965–19851 Variants →

220D

W115 (Stroke 8) · W123

220D

1968–19851 Variants →

240D

W115 (Stroke 8) · W123

240D

1973–19851 Variants →

190D

2.5

W201

190D 2.5

1986–19881 Variants →

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]

190D

Generation

W110 (Fintail)

Variant/Badge

190D

Years

1958–1968

200D

Generation

W110 (Fintail)

Variant/Badge

200D

Years

1965–1968

200D

Generation

W115 (Stroke 8)

Variant/Badge

200D

Years

1968–1976

220D

Generation

W115 (Stroke 8)

Variant/Badge

220D

Years

1968–1976

240D

Generation

W115 (Stroke 8)

Variant/Badge

240D

Years

1973–1976

200D

Generation

W123

Variant/Badge

200D

Years

1976–1985

220D

Generation

W123

Variant/Badge

220D

Years

1976–1985

240D

Generation

W123

Variant/Badge

240D

Years

1976–1985

190D

Generation

W201

Variant/Badge

190D

Years

1983–1988

190D

2.5

Generation

W201

Variant/Badge

190D 2.5

Years

1986–1988

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]

(Exclusive mode – no cross-link)

Jaguar Engine Engine Price Guide

All prices are estimates from UK specialists [ESTIMATED]

Fitting an OM621/OM622/OM626 typically takes 8–12 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer) [ESTIMATED].

(Exclusive mode – no cross-link)

USED

Supply Only

£400–£1,000

[ESTIMATED]

Fitted (Indie)

£700–£1,300

3–6 months

Jaguar Engine Engine Price Guide

All prices are estimates from UK specialists

[ESTIMATED]

USED

Supply Only

£400–£1,000

[ESTIMATED]

Fitted (Indie)

£700–£1,300

Warranty

3–6 months

Frequently Asked Questions

Expert answers to the most common BMW Engine engine questions.

Why Owners Trust Us

Trusted Suppliers – Every garage and engine rebuilder in our network is vetted, rated and reviewed by real classic Mercedes owners, as part of the Engine Finders network.

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UK Coverage – Our specialist partners span the entire UK, ensuring you can find a trusted local fitter for your classic Mercedes diesel.

Find the best Mercedes OM621/OM622/OM626 engine replacement UK drivers trust. Compare real prices from trusted specialists on EnginesMarket today and keep your classic Mercedes on the road for another 50 years.

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Trusted Suppliers – Every garage and engine rebuilder in our network is vetted, rated and reviewed by real classic Mercedes owners, as part of the Engine Finders network.

Compare Companies – We compare not just prices but real workshop reputations, warranty terms, and availability – so you know exactly who you're dealing with.

UK Coverage – Our specialist partners span the entire UK, ensuring you can find a trusted local fitter for your classic Mercedes diesel.

Find the best BMW Engine engine replacement UK drivers rely on.

Compare real prices from trusted specialists on EnginesMarket today and keep your classic Mercedes on the road for another 50 years.

Compare Mercedes OM621/OM622/OM626 Engine Prices Now