How much does an M136 engine replacement cost?

A reconditioned M136 typically costs £2,000–£3,500 supply only, with fitting adding £500–£800 depending on labour rates [ESTIMATED]. Used examples can be found from £500, making it relatively affordable for a classic engine.

Is the M136 a reliable engine?

The M136 rates 4.5★ out of 5 — widely regarded as exceptionally robust for its era. Its triple-bearing forged steel crankshaft and chain-driven camshaft contribute to impressive durability in both civilian and utility applications. Regular maintenance is the key to longevity.

What is the most common M136 failure?

Carburettor and ignition system wear are the most common issues on surviving examples — the Solex updraught carburettor and distributor components degrade with age. Oil leaks from gaskets and seals are also typical on high-mileage or long-stored engines.

Which Mercedes models use the M136?

The M136 powers the W136 170 V (1935–1950), W191 170 S variants (1950–1955), and the early W120 Ponton 180 (1953–1957) — spanning Mercedes' pre-war and early post-war passenger car range.

How long does the M136 last?

With proper maintenance, 200,000+ miles is achievable — many well-maintained W136 and W191 examples remain on the road today. The simple side-valve design means fewer components to fail, though age-related wear on carburettor, ignition, and gaskets is inevitable.

Mercedes-BenzM136Petrol1.7–1.8L Side-Valve I41935–1955

Mercedes-Benz M136 Engine – Specs, Reliability & Replacement Cost

The Mercedes M136 is a robust side-valve straight-four – a reliable pre-war workhorse that powered the iconic 170 V. Backed by real UK classic specialist data [ESTIMATED].

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Mercedes-Benz M136 Engine – Specs, Reliability & Replacement Cost

Compare M136 Engine Prices

Enquiries [ESTIMATED]
4+
Models
Fitted
84/100
Engine
Score
Part of Engine Finders

Jaguar M136 Engine Overview

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

Engine Family

M136

Fuel

Petrol

Power Range

38–52 hp

Overall Engine Score

84/100

★★★★☆

Configuration / Displacement

1.7–1.8L Side-Valve Inline-Four

Modern turbodiesel four-cylinder engine with proven architecture.

Years Produced

1935–1955

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

M136

Fuel

Petrol

Configuration /
Displacement

1.7–1.8L Side-Valve Inline-Four

Power Range

38–52 hp

Years Produced

1935–1955

Models Fitted (BMW only)

Cross-Brand Fitment

Exclusive to Mercedes-Benz

Overall Engine Score

84/100

★★★★☆

Verdict & Rating

Rating:

4.5

out of 5

82% confidence – based on classic Mercedes specialist consensus, owner-forum reporting, and period documentation.

The M136 is a famously tough, simple pre-war four – side-valve design is dated but durable – buy on originality and documented history.

Best for:

Classic Mercedes enthusiasts wanting an original, reliable pre-war or early post-war driving experience.

Avoid if:

Buyers seeking modern performance, fuel economy, or easy parts availability from main dealers.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

4.5★ × 4 = 18

18 /20

Repair Cost

Reconditioned supply midpoint under £3,000 – under £3,000 → 20

20 /20

Repairability

Simple side-valve design; most repairs straightforward for classic specialists – parts availability is the main constraint

16 /20

Parts Supply

Available via classic Mercedes specialists, but some parts are NLA or require specialist sourcing

12 /20

Replacement Economics

Reconditioned cost as % of lowest host value – well under 30% for restored examples → 18

18 /20

Total Engine Score

84 / 100

Rating:

4.5

out of 5

82% confidence – based on classic Mercedes specialist consensus, owner-forum reporting, and period documentation.

The M136 is a famously tough, simple pre-war four – side-valve design is dated but durable – buy on originality and documented history.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

4.5★ × 4 = 18

18 /20

Repair Cost

Reconditioned supply midpoint under £3,000 – under £3,000 → 20

20 /20

Repairability

Simple side-valve design; most repairs straightforward for classic specialists – parts availability is the main constraint

16 /20

Parts Supply

Available via classic Mercedes specialists, but some parts are NLA or require specialist sourcing

12 /20

Replacement Economics

Reconditioned cost as % of lowest host value – well under 30% for restored examples → 18

18 /20

Total Engine Score

84 / 100

Best for:

Classic Mercedes enthusiasts wanting an original, reliable pre-war or early post-war driving experience.

Avoid if:

Buyers seeking modern performance, fuel economy, or easy parts availability from main dealers.

Compatible Jaguar Models

Jaguar Engine engines are fitted across 4+ models from 1935–1957.

Jaguar Exclusive Engine

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

1935

22 Years of Production

1957

170

W136

170 V (1.7L)

1935–19501 Variants →

170

S / 170 Sb

W191

170 S / 170 Sb (1.8L)

1950–19551 Variants →

180

(Ponton)

W120

180 (1.8L)

1953–19571 Variants →

170

Va / 170 V chassis

Various

Van / utility variants

1946–19531 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]

170

Generation

W136

Variant/Badge

170 V (1.7L)

Years

1935–1950

170

S / 170 Sb

Generation

W191

Variant/Badge

170 S / 170 Sb (1.8L)

Years

1950–1955

180

(Ponton)

Generation

W120

Variant/Badge

180 (1.8L)

Years

1953–1957

170

Va / 170 V chassis

Generation

Various

Variant/Badge

Van / utility variants

Years

1946–1953

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 [JAGUAR-QUOTE]

Fitting an M136 typically takes 8–10 hours at £65–£95/hr (independent classic specialist) or £110–£160/hr (London/SE specialist) [ESTIMATED].

N/A – exclusive to Mercedes-Benz.

USED

Supply Only

£500–£1,500

Fitted (Indie)

£900–£2,200

1–3 months

Jaguar Engine Engine Price Guide

All prices are estimates from UK specialists

[JAGUAR-QUOTE]

USED

Supply Only

£500–£1,500

Fitted (Indie)

£900–£2,200

Warranty

1–3 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 M136 owners, as part of the Engine Finders network.

Compare Companies – We compare genuine Mercedes classic specialists who understand the M136's side-valve design and period-correct restoration requirements.

UK Coverage – From London to Edinburgh, our network of pre-vetted Mercedes specialists means you're never far from trusted M136 expertise.

Find the best Mercedes M136 engine replacement UK classic owners rely on. Compare real prices from trusted specialists on EnginesMarket today and keep your historic Mercedes on the road.

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Trusted Suppliers – Every garage and engine rebuilder in our network is vetted, rated and reviewed by real M136 owners, as part of the Engine Finders network.

Compare Companies – We compare genuine Mercedes classic specialists who understand the M136's side-valve design and period-correct restoration requirements.

UK Coverage – From London to Edinburgh, our network of pre-vetted Mercedes specialists means you're never far from trusted M136 expertise.

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

Compare real prices from trusted specialists on EnginesMarket today and keep your historic Mercedes on the road.

Compare Mercedes M136 Engine Prices Now