How much does a BMW 6 Series E24 engine replacement cost in the UK?

A reconditioned E24 engine typically costs £2,500–£15,000 supply only [BMW-QUOTE], depending on engine -the M30 six-cylinder sits at £2,500–£6,500, and the M88/S38 M-car engines at £7,000–£15,000. Fitting adds £650–£1,560. Use our calculator for a personalised figure.

What are the common problems with the BMW 6 Series E24?

Common issues include: cooling system failure (water pump, thermostat, radiator) on all M30-engined variants; timing chain guide failure on the M88 and S38 engines; oil spray bar loosening and oil leaks on the M30; and fuel injection system issues on early K-Jetronic cars -the Peirberg fuel pressure regulator is known to be lower quality than the original BMW part.

Is the BMW 6 Series E24 reliable?

It depends on which engine you choose. The M30 straight-six is one of BMW's most reliable engines ever built -many examples exceed 300,000 miles with proper servicing. The M88/3 in the M635CSi is a high-performance masterpiece but has well-documented timing chain guide and tensioner weaknesses that require proactive maintenance. The S38 in the US-spec M6 is more durable than the M88.

Which E24 engine should I avoid?

We don't recommend outright avoidance -but an M88/3 without documented timing chain guide history is the one purchase we consistently advise against. Chain guide failure is catastrophic and labour-intensive, often costing £8,000–£15,000. The early M90 in the 635CSi is rare, and parts can be difficult to source. For a sensible daily driver, the M30B35 635CSi is the smartest choice.

How do I know if my E24 engine needs replacing?

Key warning signs: M30 -overheating, coolant loss, water pump noise, or oil pressure warning; M88/S38 -rattling noise on cold start (chain guides), loss of power, or unusual engine noise. Use our diagnostic guide to identify the specific symptoms.

Is it worth replacing a BMW 6 Series E24 engine, or should I scrap the car?

Apply our 70% BMW threshold. A £6,500 M30 recon against a £15,000 E24 is 43% -viable. Against a £8,000 example, the same recon is 81% -borderline. For an M635CSi, a £10,000 recon on a £25,000 car is 40% -viable, but the car's value must justify the spend. On a tired £15,000 M635CSi, the same recon is 67% -borderline. Value the car first; if the repair exceeds 70%, walk away.

How long do BMW 6 Series E24 engines last?

The M30 straight-six can exceed 300,000 miles with proper servicing and cooling system attention. The M88/3's limiting factor is the timing chain guides and tensioner -addressed proactively, the engine is durable. The S38 is more robust than the M88. The E24's body and chassis are generally well-built and can last as long as the engine.

What is the difference between the E24 and E31?

The E24 is the first-generation BMW 6 Series, produced from 1976 to 1989. The E31 is the BMW 8 Series, produced from 1989 to 1999. The E31 was larger, more expensive, and used V8 and V12 engines -it was the E24's direct successor but was positioned above the 6 Series. The 6 Series name was revived later with the E63 (2003–2010). The E24 is a 2-door coupé only.

How do I find my BMW 6 Series E24 engine code?

Listed on the VIN plate and vehicle documentation; block stamping is visible on the block face near the timing cover. For the M30, the code is stamped on the block above the starter motor. For the M88, it's on the block face near the intake manifold. Tell us your registration and we'll identify it -20+ vetted BMW specialists will confirm it for free.

BMW 6 Series E24Coupé1976–1989

BMW 6 Series E24 Engines — The Complete UK Guide

Every engine fitted to the E24 — from the 2.8-litre M30 six-cylinder to the 3.5-litre M88 in the M635CSi and the S38 in the M6.

Real UK replacement costs, honest failure data, and the timing chain and cooling system issues that define this generation's ownership story.

Backed by real UK enquiry data [PATTERN DATA].

Explore E24 Engines

E24 Enquiries (Pattern Data)
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8+Engine Codes
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E24 Enquiries (Pattern Data)
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Engine Database

BMW 6 Series E24 Engine Codes — The Complete Database

Every engine fitted to the E24 — from the 1976 launch to the 1989 phase-out, including the 1982 update and the M635CSi/M6.

Engine CodeFuelPowerYearsReliabilityEnquiries (2025)Avg. Recon Cost

M30B28M30Petrol184 bhp1979–1987★★★☆☆PROVISIONALpending dedicated Engine Page—(pattern data)£2,500–£4,500[BMW-QUOTE]

M30B30VM30Petrol182–185 bhp1976–1979★★★☆☆PROVISIONALpending dedicated Engine Page—(pattern data)£2,800–£5,000[BMW-QUOTE]

M30B32M30Petrol197 bhp1976–1984★★★☆☆PROVISIONALpending dedicated Engine Page—(pattern data)£3,000–£5,500[BMW-QUOTE]

M90M90Petrol215 bhp1978–1982★★★☆☆PROVISIONALpending dedicated Engine Page—(pattern data)£3,500–£6,500[BMW-QUOTE]

M30B34M30Petrol182–215 bhp1982–1987★★★☆☆PROVISIONALpending dedicated Engine Page—(pattern data)£3,200–£6,000[BMW-QUOTE]

M30B35M30Petrol208–217 bhp1987–1989★★★☆☆PROVISIONALpending dedicated Engine Page—(pattern data)£3,500–£6,500[BMW-QUOTE]

M88/3M88Petrol286 bhp1984–1989★★☆☆☆PROVISIONALpending dedicated Engine Page—(pattern data)£8,000–£15,000[BMW-QUOTE]

S38S38Petrol252–256 bhp1986–1989★★★☆☆PROVISIONALpending dedicated Engine Page—(pattern data)£7,000–£12,000[BMW-QUOTE]

Overview

BMW 6 Series E24 — Overview

The E24 is the first generation of the BMW 6 Series, a grand tourer produced from January 1976 to April 1989. Designed by Paul Bracq, it replaced the E9 coupé and was produced exclusively as a 2-door coupé. The E24 shared many parts with the E12 5 Series, and in 1982 was updated with parts from the newly released E28 5 Series.

All models used petrol straight-six engines, with the majority using a version of the M30 engine family. The range-topping M635CSi (M6 in North America) was powered by the M88/3 straight-six — the first of the M6 model line.

Key Facts

PlatformBMW E24 (rear-wheel drive)
PredecessorBMW E9
SuccessorBMW E31 (8 Series) / BMW E63 (6 Series name)
Sibling Body Styles in this Generationnone — E24 is a 2-door coupé only

Market Intelligence

The E24 remains a highly sought-after modern classic, with strong demand for the 635CSi and M635CSi variants among UK collectors and enthusiasts [PATTERN DATA].

04Best & Worst Engines

Best & Worst Engines

Thin-Data Summary

Thin-Data Fallback mode — exactly one paragraph: The M30 straight-six is the backbone of the E24 range — bulletproof, torquey, and one of BMW's most durable engines ever built, with production spanning 1968 to 1994. The M30B35 in the late 635CSi (1987–1989) is the pick of the M30s, producing 217 bhp with Motronic injection and a catalytic converter. The M88/3 in the M635CSi is a masterpiece — 286 bhp from a naturally aspirated 3.5-litre, but it's high-maintenance: timing chain guides are a known weakness, and the single-row chain tensioner can fail, leading to catastrophic engine damage. The S38 in the US-spec M6 is detuned to 252 bhp and is more durable than the M88. The engines to approach with caution are the early M90 in the 635CSi — it's rare and parts can be difficult to source. For most buyers, the M30B35 635CSi is the smartest choice: bulletproof M30 reliability with 217 bhp and modern Motronic injection.

Thin-Data Summary

BMW 6 Series E24
Ownership Economics

Engine

Typical Mileage

Common Major Failure

Repair Cost (Specialist)

Replacement Cost (Recon)

Ownership Verdict

M30B28 (628CSi)80k–150k+Cooling system; oil leaks£300–£900£2,500–£4,500

Solid Choice -reliable but underpowered for the E24's weight.

M30B30V (630CS)80k–150k+Cooling system; carburettor issues£300–£900£2,800–£5,000

Solid Choice -reliable but rare; carbs need attention.

M30B32 (633CSi)80k–150k+Cooling system; oil leaks£300–£900£3,000–£5,500

Solid Choice -reliable, torquey, and well-supported.

M90 (early 635CSi)80k–150k+Cooling system; parts scarcity£400–£1,000£3,500–£6,500

Collector's Choice -rare and special, but parts can be hard to find.

M30B34 (635CSi)80k–150k+Cooling system; oil leaks£300–£900£3,200–£6,000

Solid Choice -reliable and well-supported.

M30B35 (late 635CSi)80k–150k+Cooling system; oil leaks£300–£900£3,500–£6,500

Best M30 -the most powerful and refined M30 in the E24.

M88/3 (M635CSi)60k–120kTiming chain guides; tensioner£1,500–£4,000£8,000–£15,000

Collector's Masterpiece -spectacular but expensive to maintain.

S38 (M6)60k–120kTiming chain guides; valve adjustments£1,000–£2,500£7,000–£12,000

Collector's Choice -more durable than M88, but still specialist territory.

Engine

Typical Mileage

Common Major Failure

Repair Cost (Specialist)

Replacement Cost (Recon)

Ownership Verdict

M30B28 (628CSi)80k–150k+Cooling system; oil leaks£300–£900£2,500–£4,500

Solid Choice -reliable but underpowered for the E24's weight.

M30B30V (630CS)80k–150k+Cooling system; carburettor issues£300–£900£2,800–£5,000

Solid Choice -reliable but rare; carbs need attention.

M30B32 (633CSi)80k–150k+Cooling system; oil leaks£300–£900£3,000–£5,500

Solid Choice -reliable, torquey, and well-supported.

M90 (early 635CSi)80k–150k+Cooling system; parts scarcity£400–£1,000£3,500–£6,500

Collector's Choice -rare and special, but parts can be hard to find.

M30B34 (635CSi)80k–150k+Cooling system; oil leaks£300–£900£3,200–£6,000

Solid Choice -reliable and well-supported.

M30B35 (late 635CSi)80k–150k+Cooling system; oil leaks£300–£900£3,500–£6,500

Best M30 -the most powerful and refined M30 in the E24.

M88/3 (M635CSi)60k–120kTiming chain guides; tensioner£1,500–£4,000£8,000–£15,000

Collector's Masterpiece -spectacular but expensive to maintain.

S38 (M6)60k–120kTiming chain guides; valve adjustments£1,000–£2,500£7,000–£12,000

Collector's Choice -more durable than M88, but still specialist territory.

The E24 rule

A £6,500 M30 recon against a £15,000 E24 sits at 43% -within our 70% BMW threshold. Against a £8,000 example, the same recon is 81% -borderline. The M88 is another matter: a £10,000+ recon on a £25,000 M635CSi is 40% -viable, but the car's value must justify the spend. On a tired £15,000 M635CSi, the same recon is 67% -borderline. Value the car first, then the repair.

Key Takeaways

Which E24 Costs Least To Own?
M30B28 (628CSi) -cheap parts, simple design, but underpowered.
Which E24 Costs Most To Own?
M88/3 (M635CSi) -timing chain work and specialist maintenance are expensive and essential.
Which E24 Is Best Value?
M30B35 (late 635CSi) -the sweet spot of performance, reliability, and running costs.

Common Problems

M30

Cooling System Failure

Affected models:

All E24 M30-engined variants (628CSi, 630CS, 633CSi, 635CSi).

Typical failure mileage:

60,000–100,000 miles.

Root cause:

The M30's cooling system is its Achilles' heel -plastic water pump impellers, thermostats, and radiator end tanks become brittle with age. Overheating is a common cause of head gasket failure on higher-mileage examples.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£800–£1,500

£400–£900

Water pump, thermostat, radiator replacement

Yes -essential preventative maintenance

Catastrophic (Replacement)

Dealer

Specialist

£4,000–£7,000

£2,500–£6,500

Full reconditioned M30 engine

Often 25–50% of E24 value

Our Recommendation

Replace the entire cooling system -water pump, thermostat, radiator, and hoses -every 80,000–100,000 miles. A £400–£900 preventative refresh is dramatically cheaper than the £2,500–£6,500 replacement that follows an overheating failure.

Compare M30 engine prices for your E24

M88/S38

Timing Chain Guide Failure

Affected models:

E24 M635CSi (M88/3) and M6 (S38).

Typical failure mileage:

60,000–120,000 miles.

Root cause:

The M88's single-row timing chain is a known weak point. The chain tensioner design tensions too slowly on startup, letting the chains slap the guides and wearing them out prematurely. When the guides break, the chain can skip or snap, causing piston-to-valve contact and catastrophic engine failure. The S38 is more durable -its timing chain and guide rails far outlast those on the M88.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£2,500–£4,500

£1,500–£3,000

Timing chain guides, tensioner and chain replacement

Yes -essential on high-mileage M cars

Catastrophic (Replacement)

Dealer

Specialist

£12,000–£18,000

£8,000–£15,000

Full reconditioned M88/S38 engine

Often 40–60% of M635CSi/M6 value

Our Recommendation

On any M635CSi or M6 approaching 60,000 miles without documented timing chain guide history, budget for a chain guide inspection and replacement. A £1,500–£3,000 preventative repair is dramatically cheaper than the £8,000–£15,000 replacement that follows a guide failure.

Compare M88 engine prices for your M635CSi

M30

Oil Spray Bar and Oil Leak Issues

Affected models:

All M30-engined E24 variants.

Typical failure mileage:

80,000–150,000 miles.

Root cause:

The oil spray bar under the valve cover can loosen, depriving the top of the engine of oil. Oil leaks from the valve cover gasket and oil pan are common. Early E24s also had an oil gallery manufacturing hole plugged with an aluminium seal behind the timing cover.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£500–£1,200

£300–£800

Oil spray bar tightening; gasket replacement

Yes -cheap insurance

Catastrophic (Replacement)

Dealer

Specialist

£4,000–£7,000

£2,500–£6,500

Full reconditioned M30 engine

Often 25–50% of E24 value

Our Recommendation

At every service, check the oil spray bar bolts are tight -a £300–£800 preventative check is far cheaper than the £2,500–£6,500 replacement that follows an oil starvation failure.

Compare M30 engine prices for your E24

Fuel

Injection System Issues (K-Jetronic / L-Jetronic / Motronic)

Affected models:

All E24 variants, particularly early K-Jetronic cars.

Typical failure mileage:

Age-related, not mileage-dependent.

Root cause:

The E24 used a succession of fuel injection systems -K-Jetronic (mechanical), L-Jetronic and Motronic. Early K-Jetronic systems can develop issues with the fuel distributor, warm-up regulator, and injectors. The Peirberg fuel pressure regulator is known to be lower quality than the original BMW part.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£800–£1,800

£400–£1,200

Fuel distributor rebuild; injector cleaning

Yes -but specialist work required

Catastrophic (Replacement)

Dealer

Specialist

£2,500–£5,000

£1,500–£3,500

Full fuel injection system replacement

Often 15–35% of E24 value

Our Recommendation

On any early E24, have the fuel injection system inspected and serviced by a specialist -a £400–£1,200 preventative service is far cheaper than the £1,500–£3,500 replacement that follows a failed fuel distributor.

Compare E24 fuel injection repair quotes

E24
Engine Replacement Costs -By Engine and Condition

Variant

Engine Code

Used (Supply)

Reconditioned (Supply)

Rebuilt (Supply)

Labour Hours

628CSiM30B28£1,200–£2,500£2,500–£4,500£4,000–£6,50010–14 hrs

630CS / 630CSiM30B30V£1,500–£2,800£2,800–£5,000£4,500–£7,00010–14 hrs

633CSiM30B32£1,500–£3,000£3,000–£5,500£5,000–£8,00010–14 hrs

635CSi (1978–1982)M90£2,000–£3,500£3,500–£6,500£5,500–£9,00012–16 hrs

635CSi (1982–1987)M30B34£1,800–£3,200£3,200–£6,000£5,000–£8,50012–16 hrs

635CSi (1987–1989)M30B35£2,000–£3,500£3,500–£6,500£5,500–£9,00012–16 hrs

M635CSiM88/3£3,500–£7,000£8,000–£15,000£12,000–£20,00018–24 hrs

M6 (US/Japan)S38£3,000–£6,000£7,000–£12,000£10,000–£16,00018–24 hrs

No Generation variance note required -no Engine Page baseline exists for these engines yet. Costs are sourced from UK specialist suppliers [BMW-QUOTE].

Diesel & Petrol Lineup

Petrol Variants

Scope note: All variants listed are BMW 6 Series E24 only. The E24 was produced exclusively as a 2-door coupé -no estate, convertible or saloon variants exist. The M6 was the North American and Japanese market name for the M635CSi. The successor to the E24 was the E31 8 Series (1989–1999), with the 6 Series name later revived on the E63.

Market Intelligence

Most Requested Engines (2025)

Most Requested Variants

Average Replacement Cost

Most Common Failures

Most Requested Engines (2025)

Most Requested Variants

Average Replacement Cost

Most Common Failures

Most Requested Engines (2025)

Most Requested Variants

Average Replacement Cost

Most Common Failures

Diesel & Petrol Lineup

Petrol Variants

Market Intelligence

Most Requested Engines (2025)

Most Requested Variants

Average Replacement Cost

Most Common Failures

Most Requested Engines (2025)

Most Requested Variants

Average Replacement Cost

Most Common Failures

Most Requested Engines (2025)

Most Requested Variants

Average Replacement Cost

Most Common Failures

FAQ

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BMW 6 Series E24 Engines — The Complete UK Guide

BMW 6 Series E24 Engine Codes — The Complete Database

BMW 6 Series E24 — Overview

Best & Worst Engines

BMW 6 Series E24 Ownership Economics

Common Problems

E24Engine Replacement Costs -By Engine and Condition

Diesel & Petrol Lineup

Market Intelligence

Diesel & Petrol Lineup

Market Intelligence

FAQ

Why UK BMW 6 Series E24 OwnersTrust BMWEngines.uk

BMW 6 Series E24
Ownership Economics

E24
Engine Replacement Costs -By Engine and Condition

Why UK BMW 6 Series E24 Owners
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