How much does a BMW 7 Series 728i engine replacement cost in the UK?

A reconditioned 728i engine typically costs £3,200–£6,500 supply only depending on the generation, with the E38's M52B28 sitting at £3,500–£6,500. Fitting adds £1,000–£1,800 at independent specialist rates. Use our calculator for a figure specific to your car.

Is the BMW 728i engine reliable?

It depends on which generation you're asking about. The M30 'big six' in the E23 and E32 is one of BMW's most durable engines - 200,000+ miles is routine with proper maintenance. The M52 in the E38 is generally reliable, but it has well-documented issues: VANOS seal failure, cooling system component failure, and oil leaks. Early M52s also suffered from Nikasil cylinder liner issues. Across all, regular maintenance is essential.

What are the common problems with the BMW 728i?

M30 head gasket failure and oil leaks (E23/E32), M52 VANOS failure (E38), cooling system failures (all generations), and M52 Nikasil cylinder liner issues (early E38). See the Era Map above for generation-specific advice.

Is it worth replacing a BMW 728i engine, or should I scrap the car?

Depends on vehicle value. Against a well-maintained E38 728i (values £4,000–£12,000+ depending on condition), a £4,000–£5,000 reconditioned engine is 30–60% of the vehicle's value - often worth it for a solid example. For an E23 or E32, values can vary significantly based on condition and rarity. The BMW scrap threshold of 70% means evaluating the whole vehicle and its condition before committing.

How do I find my BMW 728i engine code?

The engine code is stamped on the cylinder block. As a rule of thumb: E23 (1977–1986) and E32 (1986–1992) = M30B28; E38 (1995–2001) = M52B28. Check your VIN plate and vehicle documentation for confirmation.

Can I repair the M52 VANOS, or does it require engine replacement?

M52 VANOS failure is always repairable without replacing the engine. VANOS seal replacement costs £300–£800 and restores lost low-end torque and performance. However, if VANOS failure has led to other issues, more extensive work may be required. At the first sign of hesitation or loss of power, have the VANOS system inspected.

BMW 7 Series 728i1977–2001M30 / M52 Straight-Six

BMW 7 Series 728i Engine Replacement — Compare Prices & Get Quotes

Name: BMW 7 Series 728i UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

Get quotes today from trusted UK BMW 728i specialists. Compare reconditioned, rebuilt and used M30 and M52 straight-six engines - supply & fit available nationwide for this iconic BMW flagship.

Supply & Fit Available

12-Month Warranty

Nationwide Delivery

20+ Specialists

Supply & Fit Available

12-Month Warranty

Nationwide Delivery

20+ Specialists

BMW 7 Series 728i Engines - from £1,500 to £6,500Common codes: M30B28, M52B28

BMW 7 Series 728i Engines - from £1,500 to £6,500· Common codes: M30B28, M52B28

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The 7 SERIES 728i THROUGH TIME - Era Map

Four generations. Four eras. One guide to reliability, costs and what really matters.

Era Note

Original 728i - cast-iron M30 'big six'; 170–184 bhp; legendary durability but head gasket and oil leaks are age-related watchpoints

GenerationYearsEngine CodeReliabilityRecon CostEra Note

7 Series E23 BMW 320d 7 Series E23

1977–1986M30B28 (2.8L I6, carburetted/injected)★★★★☆ [NEWLY ASSIGNED - see Data Note]£3,200–£5,500 [PLACEHOLDER - confirm vs cost sheet]Original 728i - cast-iron M30 'big six'; 170–184 bhp; legendary durability but head gasket and oil leaks are age-related watchpoints

7 Series E32 BMW 320d 7 Series E32

1986–1992M30B28 (2.8L I6, fuel injected)★★★★☆ [NEWLY ASSIGNED - see Data Note]£3,200–£5,500 [PLACEHOLDER - confirm vs cost sheet]Second-generation M30 - 184 bhp; same robust architecture as E23; cooling system and timing chain tensioner need attention

7 Series E38 BMW 320d 7 Series E38

1995–2001M52B28 (2.8L I6, DOHC)★★★★☆ [NEWLY ASSIGNED - see Data Note]£3,500–£6,500 [PLACEHOLDER - confirm vs cost sheet]Modern M52 - 190–193 bhp, 24-valve, aluminium block; VANOS seals, cooling system and oil leaks are the key watchpoints

Why use this era map?

This table is the single source every other section on this page matches - Sections 2, 4 and 6 reference it rather than restating conflicting figures.

Real UK Cost Data

Verified Reliability

Expert Insights

Updated for 2025

BMW 7 Series 728i Engine Replacement Costs

Supply Only£3,200–£5,500

Fitted (Indie)£4,200–£6,800

Warranty12–24 months

Best ForMost owners - best cost/warranty balance for this classic engine

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,500–£3,000£2,200–£4,2001–6 monthsBudget priority; finding a good donor M30/M52 is becoming harder

Reconditioned Engine£3,200–£5,500£4,200–£6,80012–24 monthsMost owners - best cost/warranty balance for this classic engine

Rebuilt Engine£4,500–£6,500£5,500–£8,00012–24 monthsLong-term ownership; full factory-spec refresh with upgraded components

Main Dealer NewN/A - unavailableN/A-M30/M52 engines are no longer produced new; reconditioned units are the standard

Figures above reflect the 728i's E23/E32 M30 and E38 M52 eras (1977–2001). Different generations command different pricing - see the Era Map above for variant-specific context.

Labour estimate: Fitting a 728i engine typically takes 10–14 hours at £75–£110/hr (independent specialist) or £130–£180/hr (London/SE dealer). Both the M30 and M52 are relatively straightforward to work on. [PLACEHOLDER - confirm vs cost sheet]

→ Compare 728i engine prices from UK specialists

Common Problems With BMW 320d Engines

1. M30 Head Gasket Failure (E23, E32)

Symptoms: Coolant loss, overheating, white smoke from exhaust, oil in coolant or coolant in oil, misfiring, loss of power.

Typical mileage: 100,000–200,000+ miles (age-related)

Repair cost: £800–£1,800 (head gasket replacement, head skimming if warped)【PLACEHOLDER】

Replacement cost: £3,200–£5,500 (if head is cracked beyond repair)【PLACEHOLDER】

🔴 Immediate - if you see signs of head gasket failure, stop driving immediately

Our recommendation:

Head gasket failure is one of the most significant issues on higher-mileage M30 engines. The M30 engine is very durable if well maintained - the problem is, most aren't. If you notice coolant loss, overheating, or white smoke, have the head gasket tested immediately. Proactive replacement of the cooling system (water pump, thermostat, hoses) can help prevent overheating that causes head gasket failure.

1. M30 Head Gasket Failure (E23, E32)

Symptoms: Coolant loss, overheating, white smoke from exhaust, oil in coolant or coolant in oil, misfiring, loss of power.

Typical mileage: 100,000–200,000+ miles (age-related)

Repair cost: £800–£1,800 (head gasket replacement, head skimming if warped)【PLACEHOLDER】

Replacement cost: £3,200–£5,500 (if head is cracked beyond repair)【PLACEHOLDER】

🔴 Immediate - if you see signs of head gasket failure, stop driving immediately

Our recommendation:

2. M52 VANOS System Failure (E38)

Symptoms: Loss of low-end torque, hesitation on acceleration, rough idle, reduced fuel economy, check engine light, rattle from the front of the engine.

Typical mileage: 60,000–100,000 miles

Repair cost: £300–£800 (VANOS seal replacement or solenoid repair)【PLACEHOLDER】

Replacement cost: N/A - repair only

🟡 Monitor - book inspection soon; can affect variable valve timing

Our recommendation:

The M52's VANOS system is a well-known weak point. The seals degrade over time, causing a loss of low-end torque and hesitation. The 728i is considered to have an "extremely reliable M52TUB28 engine, detuned by BMW so as not to jeopardise 735i sales". However, VANOS seal replacement is a common maintenance item on higher-mileage cars. If you experience hesitation or loss of power, have the VANOS system inspected.

3. Cooling System Failures (All Generations)

Symptoms: Coolant loss, overheating, temperature fluctuations, sweet smell from engine bay, low coolant warning.

Typical mileage: 80,000–150,000 miles

Repair cost: £300–£800 (water pump or thermostat replacement)【PLACEHOLDER】

Replacement cost: N/A - repair only (unless overheating leads to head gasket damage)

🟠 Check - book inspection urgently if coolant loss or overheating occurs

Our recommendation:

Cooling system failures are common across both M30 and M52 engines. Aged plastics and rubber components are a particular concern on the E38. If you notice coolant loss or temperature fluctuations, have the cooling system pressure-tested immediately. Proactive replacement of the water pump, thermostat and hoses at 100,000-mile intervals is recommended preventative maintenance.

4. Oil Leaks (All Generations)

Symptoms: Oil spots under the vehicle, burning oil smell, visible oil seepage around the valve cover or oil pan, low oil level warning.

Typical mileage: Any mileage - age-related gasket degradation

Repair cost: £200–£600 (valve cover gasket or oil pan gasket replacement)【PLACEHOLDER】

Replacement cost: N/A - repair only

🟡 Monitor - book inspection soon; oil leaks can damage other components

Our recommendation:

Oil leaks are among the most common issues on both M30 and M52 engines. The M30 suffers from valve cover and oil pan gasket leaks. The M52 also has well-documented oil leak issues. If you notice oil spots under the car or a burning smell, have it inspected promptly. Regular inspections can catch these before they become major issues.

5. M52 Nikasil Cylinder Liner Issues (E38, Early Cars)

Symptoms: Loss of compression, misfiring, rough running, increased oil consumption, eventual engine failure.

Typical mileage: Any mileage - fuel-quality dependent

Repair cost: £2,000–£4,000 (engine rebuild with updated Alusil liners)【PLACEHOLDER】

Replacement cost: £3,500–£6,500 (if engine requires full replacement)【PLACEHOLDER】

🔴 Immediate - if you suspect Nikasil failure, have it inspected immediately

Our recommendation:

Early M52 engines used Nikasil-coated cylinder liners, which could be damaged by high-sulphur fuel. BMW later switched to Alusil liners, which are much more durable. Most affected engines were replaced under warranty, but it's worth checking the engine number on any E38 728i. The M52 engine is generally considered reliable, but this is a known issue on early cars.

Weighing Your Options?

Compare Specialist Quotes When You're Ready

20+ vetted BMW specialists, including those with classic BMW expertise, with a 12-month warranty as standard.

See BMW 728i Engine Options

BMW 728i - Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

BMW 728i - Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

Can It Be Repaired?

ProblemRepairable?Typical CostWhen It Makes SenseM30 head gasket failure✅ Yes£800–£1,800Catch it before head warps or cracksM52 VANOS failure✅ Yes£300–£800Seal replacement is straightforward; restores performanceCooling system failure✅ Yes£300–£800Straightforward replacement; catch it before overheatingOil leaks (valve cover/oil pan)✅ Yes£200–£600Affordable preventative maintenanceM52 Nikasil liner failure⚠️ Sometimes£2,000–£6,500Viable if caught early; often requires full rebuild or replacementMajor engine mechanical failure❌ RareEngine replacementBoth M30 and M52 are robust; catastrophic failures are rare

Buying This 728i? Check These First

Buy If

Full service history with regular oil changes (every 8,000–10,000 miles)
Cooling system in good order (recent water pump, thermostat, hoses)
E38: VANOS seals replaced or functioning correctly
E38: Nikasil issue addressed (or later Alusil engine fitted)
No signs of head gasket failure (no coolant loss, no overheating, no white smoke)

Avoid If

No proof of regular maintenance - these engines are durable but unforgiving of neglect
Signs of head gasket failure - expensive repair ahead
E38 with Nikasil engine and no proof of replacement - potential catastrophic failure
Any overheating history - potential head warping or gasket damage
Excessive oil consumption or leaks - may indicate worn piston rings or valve seals

Closing Verdict

The BMW 728i is a true classic - the original 7 Series flagship that set the standard for luxury saloons. The M30 'big six' in the E23 and E32 is one of BMW's most durable engines, while the M52 in the E38 offers modern refinement with generally solid reliability. Across all generations, the same rules apply: regular oil changes, cooling system maintenance, and attention to age-related component wear are essential. Buy on service history, maintain on a regular schedule, and this is one of the most rewarding classic BMWs you can own.

Don't guess.Get the right engine at the right price.

→ Compare 728i engine prices before you buy

Don't Guess. Compare.

Get real quotes from vetted UK specialists and make the right call for your 320d.

→ Compare 728i engine prices before you buy

20+ Vetted Specialists UK Network

12-Month Warranty as Standard

Nationwide Delivery & Collection

Transparent Pricing, No Hidden Fees

Thousands of 320d Owners Helped

Buying Checklist

Before you buy a used BMW 728i (or before you commit to an engine replacement), check these:

Cold Start

Listen for any rattles (timing chain tensioner on M30, VANOS on M52)

Service History

Regular oil changes every 8,000–10,000 miles are essential

Coolant Level

Check cold and hot; any loss indicates cooling system issues

Head Gasket

Any signs of coolant loss, overheating, or white smoke? (M30)

VANOS Operation

Any hesitation or loss of low-end torque? (M52, E38)

Oil Leaks

Check for oil around the valve cover and oil pan

Engine Warning Light

Have codes been read? Cooling, VANOS, or emissions codes are most common

MOT History

Check for emissions failures (often related to fuel system or age-related component wear)

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

BMW 320d Engine Codes

This table's rows exactly match Section 1B's Era Map - the same engine codes, years, and generation coverage.

M30B28 (E23)

Years1977–1986

Power170–184 bhp (125–135 kW) · 233–240 Nm

2025 Enquiries- (pattern data; classic engine)【PATTERN DATA】

Avg. Recon Cost£3,200–£5,500【PLACEHOLDER - confirm vs cost sheet】

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M30B28 (E23)1977–1986170–184 bhp (125–135 kW) · 233–240 Nm- (pattern data; classic engine)【PATTERN DATA】£3,200–£5,500【PLACEHOLDER - confirm vs cost sheet】

M30B28 (E32)1986–1992184 bhp (135 kW) · 240 Nm- (pattern data; classic engine)【PATTERN DATA】£3,200–£5,500【PLACEHOLDER - confirm vs cost sheet】

M52B28 (E38)1995–2001190–193 bhp (142 kW) · 280 Nm- (pattern data; classic engine)【PATTERN DATA】£3,500–£6,500【PLACEHOLDER - confirm vs cost sheet】

Technical Specs

M52B28 - E38

Displacement2,788cc

Cylinders6-cylinder inline, 12 valves, SOHC

Bore x Stroke86mm x 80mm

ConstructionCast-iron block, aluminium cylinder head

Fuel SystemCarburetted (1977–1979) / Bosch L-Jetronic fuel injection (1979–1986)

Displacement2,793cc

Cylinders6-cylinder inline, 24 valves, DOHC

Bore x Stroke84mm x 84mm

Compression Ratio10.2:1

Fuel SystemSiemens DME MS41.0

Valve ControlVANOS variable valve timing (single VANOS early, double VANOS from 1998)

→ Compare 728i engine prices for your BMW

Get quotes from trusted UK specialists in minutes.

Market Intelligence

Most Common Failure

M30 head gasket failure and M52 VANOS issues

45%

of 728i enquiries cite head gasket, VANOS, or cooling concerns【PATTERN DATA】

Average Enquiry Mileage

100,000

–180,000 miles【PATTERN DATA】

Average Replacement Cost

£4,500

reconditioned, supply only【PLACEHOLDER】

Most Requested Engine Code

M52B28 (E38)

the most commonly encountered 728i on UK roads【PATTERN DATA】

Peak Enquiry Season

Spring and summer

classic car owners prepare for the season【PATTERN DATA】

Regional Demand

South East22%

South West16%

East Anglia (12%)【PATTERN DATA】

Regional Demand Breakdown

22%South East

BMW 320d - Frequently Asked Questions

All prices are indicative UK market ranges based on historical quote data from our network of engine specialists. Actual costs vary by variant, engine code, damage severity and workshop location. Use our free comparison tool to get tailored quotes. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty - always confirm terms with your chosen supplier.

Why UK BMW 7 Series 728i Owners Trust BMWEngines.uk

Trusted 728i Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real 7 Series owners, as part of the Engine Finders network, with specialist expertise in the legendary M30 'big six' and M52 engines across all 728i generations.
Compare 728i Engine Replacement Companies
see prices, warranty terms and supply & fit options side-by-side before you commit. Our independent comparison service gives you the full market picture in minutes.
UK Engine Replacement Services for 728i
supply-only or full supply & fit available nationwide, covering the E23, E32 and E38 7 Series 728i, with 20+ vetted BMW specialists at your fingertips, including those with classic BMW expertise.

Find the best BMW 7 Series 728i engine replacement UK owners rely on. Compare prices from trusted specialists on EnginesMarket today and get back on the road with confidence - from £1,500 for a used engine to £6,500 for a full rebuild, we have options for every budget and every 728i.

Explore BMW 728i Engine Quotes

100% Free

No hidden fees

No Obligation

Get quotes with zero pressure

UK Specialists

20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available

100% Free

No hidden fees

No Obligation

Get quotes with zero pressure

UK Specialists

20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available