How much does a BMW M70/M73 engine replacement cost?

A reconditioned M70 or M73 typically costs £6,000–£9,000 supply only [BMW-QUOTE], varying by exact variant and condition. Fitting adds £2,000–£4,500 depending on specialist rates. Use our calculator for a figure specific to your car.

Is the BMW M70/M73 a reliable engine?

Yes – the M70 and M73 are fundamentally robust V12s with forged steel crankshafts and durable bottom ends. However, age-related issues (cooling system, ignition components, oil leaks) are common and expensive. Regular maintenance is essential.

What is the most common BMW M70/M73 failure?

Cooling system failure is the most critical – plastic radiator necks and expansion tanks degrade with age, causing overheating and potential head gasket failure. Also common are ignition coil failure (12 coils, expensive) and oil leaks from valve covers.

Which BMW models use the M70/M73?

The M70 powered the E31 850i, E32 750iL, and the rare E34 550i prototype. The M73 appeared in the E31 850Ci (1994–1999) and E38 750iL (1994–2001).

How long does the BMW M70/M73 last?

With meticulous maintenance, these engines can exceed 200,000 miles. However, the cost of a full rebuild (£9,000+) and parts scarcity make preventative maintenance financially sensible.

BMW M70 / M73 Engine -Specs, Reliability & Replacement Cost

The BMW M70 and M73 are BMW's flagship V12 petrol engines -smooth and powerful, but complex and expensive to maintain. Backed by real UK specialist enquiries [ESTIMATED].

Compare M70/M73 Engine Prices

BMW M70 / M73 Engine -Specs, Reliability & Replacement Cost

Compare M70/M73 Engine Prices

BMW M70 / M73 Engine Overview

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

Engine Family

BMW M70 / M73

Fuel

Petrol (Naturally Aspirated)

Power Range

296–326 hp

BMW-VERIFIED

Overall Engine Score

62/100

★★★★☆

Configuration / Displacement

V12, 5.0L (M70) / 5.4L (M73)

Modern turbodiesel four-cylinder engine with proven architecture.

Years Produced

1987–2001

Over a decade of production and continuous development.

Models Fitted (BMW only)

8 Series (E31), 7 Series (E32, E38), 5 Series (E34)

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

Cross-Brand Fitment

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

BMW M70 / M73

Fuel

Petrol (Naturally Aspirated)

Configuration /
Displacement

V12, 5.0L (M70) / 5.4L (M73)

Power Range

296–326 hp

BMW-VERIFIED

Years Produced

1987–2001

Models Fitted (BMW only)

8 Series (E31), 7 Series (E32, E38), 5 Series (E34)

Cross-Brand Fitment

Overall Engine Score

62/100

★★★★☆

Verdict & Rating

Rating:

3.5

out of 5

85% confidence -based on specialist workshop consensus and owner-club documented history.

The M70 and M73 are refined, durable V12s -but complexity and parts scarcity make ownership costly -buy only with full documented history.

Best for:

Collectors and enthusiasts who value V12 smoothness and are prepared for specialist maintenance.

Avoid if:

You're on a tight budget or cannot afford V12-level parts and labour costs.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

3.5★ × 4 = 14

14 /20

Repair Cost

Reconditioned midpoint ~£7,500 – falls in £7,000–£9,999 bracket → 8

8 /20

Repairability

V12 complexity adds labour time; some repairs are manageable, others require engine-out

12 /20

Parts Supply

Some parts still available but expensive; many items NLA or specialist-only

12 /20

Replacement Economics

Reconditioned cost vs. lowest host-value (~£5,000) = ~150% – over threshold but classic values support → 16

16 /20

Total Engine Score

62 / 100

Rating:

3.5

out of 5

85% confidence -based on specialist workshop consensus and owner-club documented history.

The M70 and M73 are refined, durable V12s -but complexity and parts scarcity make ownership costly -buy only with full documented history.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

3.5★ × 4 = 14

14 /20

Repair Cost

Reconditioned midpoint ~£7,500 – falls in £7,000–£9,999 bracket → 8

8 /20

Repairability

V12 complexity adds labour time; some repairs are manageable, others require engine-out

12 /20

Parts Supply

Some parts still available but expensive; many items NLA or specialist-only

12 /20

Replacement Economics

Reconditioned cost vs. lowest host-value (~£5,000) = ~150% – over threshold but classic values support → 16

16 /20

Total Engine Score

62 / 100

Best for:

Collectors and enthusiasts who value V12 smoothness and are prepared for specialist maintenance.

Avoid if:

You're on a tight budget or cannot afford V12-level parts and labour costs.

Compatible BMW Models

BMW M70 / M73 engines are fitted across 8 Series (E31), 7 Series (E32, E38), 5 Series (E34) from 1987–2001.

BMW Exclusive Engine

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

1987

14 Years of Production

2001

Engine

BMW 8 Series

E31

850i, 850Ci (M70B50)1 Variants →

1989–1994

M70 5.0L V12

BMW 8 Series

E311 Variants →

850Ci

(M73B54)

1994–1999

M73 5.4L V12

BMW 7 Series1 Variants →

E32

750iL, 750i (M70B50)

1987–1994

M70 5.0L V121 Variants →

BMW

7 Series

E38

750iL · 750i (M73B54)

1994–20012 Variants →

M73

5.4L V12

BMW 5 Series

E34

540i (M60) -Note: V8, not V121 Variants →

BMW 5 Series

E341 Variants →

Other BMW Models

M70 / M73 also appears in limited variants and markets.

View full details →

Compatibility Verified

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

Engine

Generation

BMW 8 Series

Variant/Badge

E31

Years

850i, 850Ci (M70B50)

1989–1994

Generation

M70 5.0L V12

Variant/Badge

BMW 8 Series

Years

E31

850Ci

(M73B54)

Generation

1994–1999

Variant/Badge

M73 5.4L V12

Years

BMW 7 Series

E32

Generation

750iL, 750i (M70B50)

Variant/Badge

1987–1994

Years

M70 5.0L V12

BMW

7 Series

Generation

E38

Variant/Badge

750iL, 750i (M73B54)

Years

1994–2001

M73

5.4L V12

Generation

BMW 5 Series

Variant/Badge

E34

Years

540i (M60) -Note: V8, not V12

Generation

Variant/Badge

BMW 5 Series

Years

E34

Other BMW Models

M70 / M73 also appears in limited variants and markets.

View full details ›

Compatibility Verified

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

(Exclusive mode – no cross-link)

BMW M70 / M73 Engine Price Guide

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

Fitting an M70/M73 typically takes 20–28 hours at £75–£110/hr (independent specialist) or £130–£180/hr (London/SE prestige specialist) [BMW-QUOTE].

(Exclusive mode – no cross-link)

USED

Supply Only

£2,500–£4,500

Fitted (Indie)

£4,000–£6,500

3–6 months

BMW M70 / M73 Engine Price Guide

All prices are estimates from UK specialists

[BMW-QUOTE]

USED

Supply Only

£2,500–£4,500

Fitted (Indie)

£4,000–£6,500

Warranty

3–6 months

Frequently Asked Questions

Expert answers to the most common BMW M70 / M73 engine questions.

Why Owners Trust Us

Trusted Suppliers -Every garage and engine rebuilder in our network is vetted, rated and reviewed by real BMW V12 owners, as part of the Engine Finders network.

Compare Companies -We compare real quotes from UK specialists so you can make an informed decision without the hassle of calling around.

UK Coverage -Our network spans England, Scotland, Wales and Northern Ireland, ensuring you find a trusted specialist near you.

Find the best BMW M70 or M73 engine replacement UK enthusiasts rely on. Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare BMW M70/M73 Engine Prices Now →

Trusted Suppliers -Every garage and engine rebuilder in our network is vetted, rated and reviewed by real BMW V12 owners, as part of the Engine Finders network.

Compare Companies -We compare real quotes from UK specialists so you can make an informed decision without the hassle of calling around.

UK Coverage -Our network spans England, Scotland, Wales and Northern Ireland, ensuring you find a trusted specialist near you.

Find the best BMW M70 / M73 engine replacement UK drivers rely on.

Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare BMW M70/M73 Engine Prices Now