How much does a BMW 735i engine replacement cost in the UK?

A reconditioned 735i engine costs £2,500–£8,500 supply only depending on generation. E23/E32 M30 engines start around £2,500; E38 M62 units start around £3,500; E65/E66 N62 units start around £4,500. Fitting adds £1,200–£2,500. Main dealer new engines are no longer available. Use our calculator for a figure specific to your car.

Is the BMW 735i engine reliable?

It depends entirely on which generation you have. The E23 and E32 M30 straight-six is widely considered bulletproof - one of BMW's most durable engines ever. The E38 M62 V8 is smooth and refined but has cooling system vulnerabilities. The E65/E66 N62 V8 is the most complex, with valve stem seal and Valvetronic issues being common. The older the car, the simpler and more reliable the engine tends to be.

What are the common problems with the BMW 735i?

E23/E32 M30: Electronics, HVAC, fuel pumps - the engine itself is bulletproof. E38 M62: Cooling system failures (radiator, expansion tank, water pump), VANOS issues. E65/E66 N62: Valve stem seal failure (blue smoke on startup), Valvetronic issues (misfires), coolant pipe corrosion.

Is it worth replacing a BMW 735i engine, or should I scrap the car?

Depends on vehicle value and which generation. Against a well-kept £8,000 E38 735i, a £5,000 recon is 63% - approaching our 70% BMW threshold. Against a tired £3,000 example, the same recon exceeds the threshold. For E23/E32 classics, values are rising - a £4,000 recon against a £10,000 car is 40% - worth it. For E65/E66, values are lower - a £6,500 recon against a £4,000 car is rarely justified.

How do I find my BMW 735i engine code?

Listed on the VIN plate and vehicle documentation. E23 (1977–1986): M30B35. E32 (1986–1992): M30B35. E38 (1996–2001): M62B35. E65/E66 (2001–2008): N62B36. The chassis code is the easiest tell.

BMW 735i1977–20084 Engine Generations

BMW 735i Engine Replacement — Compare Prices & Get Quotes

Name: BMW 735i UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

Get quotes today from trusted UK BMW 7 Series specialists. Compare reconditioned, rebuilt and used M30, M62 and N62 engines - from the classic E23 to the modern E65 - supply & fit available nationwide.

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BMW 735i Engines - from £1,500 to £8,500Common codes: M30B35, M62B35, N62B36

BMW 735i Engines - from £1,500 to £8,500· Common codes: M30B35, M62B35, N62B36

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The 735i THROUGH TIME - Era Map

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

Era Note

The original 7 Series - a bulletproof M30 straight-six. Electronics and HVAC are the real weak points.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

E23 (First Generation) BMW 320d E23 (First Generation)

1977–1986M30B35 (3.4L/3.5L Straight-Six)★★★★☆ [NEWLY ASSIGNED - see Data Note]£2,500–£4,500 [PLACEHOLDER - confirm vs cost sheet]The original 7 Series - a bulletproof M30 straight-six. Electronics and HVAC are the real weak points.

E32 (Second Generation) BMW 320d E32 (Second Generation)

1986–1992M30B35 (3.4L Straight-Six)★★★★☆ [NEWLY ASSIGNED - see Data Note]£2,500–£4,500 [PLACEHOLDER]The most successful 735i - nearly 100,000 sold. Same bulletproof M30.

E38 (Third Generation) BMW 320d E38 (Third Generation)

1996–2001M62B35 (3.5L V8)★★★☆☆ [NEWLY ASSIGNED - see Data Note]£3,500–£6,500 [PLACEHOLDER]BMW's first V8 735i. Smooth and refined, but cooling systems and VANOS need vigilance.

E65/E66 (Fourth Generation) BMW 320d E65/E66 (Fourth Generation)

2001–2008N62B36 (3.6L V8)★★½☆☆ [NEWLY ASSIGNED - see Data Note]£4,500–£8,500 [PLACEHOLDER]The most complex 735i. Valvetronic, valve stem seals, and coolant pipes are the main concerns.

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 735i Engine Replacement Costs

Supply Only£3,500–£6,500

Fitted (Indie)£5,000–£8,000

Warranty12–24 months

Best ForMost owners - best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,500–£4,500£2,500–£6,0001–6 monthsBudget priority; classic car projects

Reconditioned Engine£3,500–£6,500£5,000–£8,00012–24 monthsMost owners - best cost/warranty balance

Rebuilt Engine£5,000–£8,500£6,500–£10,00012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer NewN/AN/AN/ANo longer available from BMW - these engines are out of production

Figures above reflect the varying costs across the 735i's four generations. M30 engines (E23/E32) are the cheapest to replace; N62 engines (E65/E66) are the most expensive due to complexity. Main dealer new engines are no longer available for any 735i generation.

Labour estimate: Fitting a 735i engine typically takes 12–20 hours at £70–£100/hr (independent) or £120–£180/hr (London/SE dealer). V8 engines (E38/E65) require more labour than the straight-six (E23/E32).

→ Compare 735i engine prices from UK specialists

Common Problems With BMW 320d Engines

1. Cooling System Failures - M62 V8 (E38 735i)

Symptoms: Coolant loss, overheating, temperature gauge fluctuations, sweet smell from the engine bay, radiator or expansion tank cracks.

Typical mileage: 60,000–100,000 miles

Repair cost: £400–£900 (cooling system overhaul)【PLACEHOLDER - confirm vs cost sheet】

Replacement cost: £3,500–£6,500 (if overheating leads to head gasket or engine failure)

🟠 Check - book inspection urgently

Our recommendation:

The M62 V8's cooling system is its Achilles heel. The plastic radiator, expansion tank, and water pump are known failure points. If you're experiencing coolant loss or overheating, have the entire cooling system inspected. Preventative replacement of the water pump, thermostat, and expansion tank is recommended at 60,000-mile intervals. This applies to the E38 735i only.

Read the full cooling system failure guide

1. Cooling System Failures - M62 V8 (E38 735i)

Symptoms: Coolant loss, overheating, temperature gauge fluctuations, sweet smell from the engine bay, radiator or expansion tank cracks.

Typical mileage: 60,000–100,000 miles

Repair cost: £400–£900 (cooling system overhaul)【PLACEHOLDER - confirm vs cost sheet】

Replacement cost: £3,500–£6,500 (if overheating leads to head gasket or engine failure)

🟠 Check - book inspection urgently

Our recommendation:

Read the full cooling system failure guide

2. Valve Stem Seal Failure - N62 V8 (E65/E66 735i)

Symptoms: Blue smoke from exhaust on startup, especially after idling for 5+ minutes, excessive oil consumption, smoke screen on acceleration.

Typical mileage: 60,000–120,000 miles

Repair cost: £1,500–£3,500 (valve stem seal replacement)【PLACEHOLDER - confirm vs cost sheet】

Replacement cost: £4,500–£8,500 (if oil starvation leads to engine failure)

🟠 Check - book inspection urgently

Our recommendation:

The N62's valve stem seals are a notorious failure point. If you notice blue smoke on startup or after extended idling, have the valve stem seals inspected immediately. Left unchecked, oil consumption can lead to catalytic converter failure and, in extreme cases, engine damage. This applies exclusively to the E65/E66 735i.

Read the full valve stem seal failure guide

3. Valvetronic / Misfire Issues - N62 V8 (E65/E66 735i)

Symptoms: Misfire under light throttle below ~2000 RPM, especially when cold; runs fine at higher RPMs; rough idle; engine warning light.

Typical mileage: 60,000–120,000 miles

Repair cost: £500–£1,500 (Valvetronic motor or sensor replacement)【PLACEHOLDER - confirm vs cost sheet】

Replacement cost: £4,500–£8,500 (if left untreated)

🟡 Monitor - book inspection soon

Our recommendation:

Valvetronic issues are common on the N62. The system uses an electric motor to control valve lift, and these motors or their sensors can fail. If you experience misfires or rough running, have the Valvetronic system diagnosed. This applies exclusively to the E65/E66 735i.

Read the full Valvetronic failure guide

Weighing Your Options?

Compare Specialist Quotes When You're Ready

20+ vetted BMW specialists, every 735i era covered - from M30 to N62 - with a 12-month warranty as standard.

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735i - 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.

735i - 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 SenseCooling system failure (M62)✅ Yes£400–£900Well-understood fix; preventative replacement recommendedValve stem seal failure (N62)✅ Yes£1,500–£3,500Specialist repair; cheaper than engine replacementValvetronic issues (N62)✅ Yes£500–£1,500Specialist diagnosis and repairM30 engine wear (E23/E32)✅ Yes£500–£2,000The M30 is rebuildable and parts are availableTiming chain failure (N62)❌ Usually No£4,500–£8,500Typically requires full engine replacement

Buying This 735i? Check These First

Buy If

E23/E32: A well-maintained M30 with documented service history - these are bulletproof
E38: Cooling system overhaul completed (water pump, thermostat, radiator, expansion tank)
E65/E66: Valve stem seals replaced and Valvetronic system inspected
Any generation: Full service history with evidence of regular oil changes

Avoid If

E38: Coolant loss or overheating with no documented cooling system work
E65/E66: Blue smoke on startup (valve stem seals) or misfires (Valvetronic)
Any generation: Poor service history - these are complex, high-mileage cars now
Engine warning light with no diagnosis

Closing Verdict

The 735i badge spans four decades of BMW flagship engineering - from the bulletproof M30 straight-six of the E23 and E32, through the refined M62 V8 of the E38, to the complex N62 V8 of the E65. The M30 cars are the most reliable; the N62 cars are the most demanding. Buy the generation that matches your budget and tolerance for complexity - but buy on documented history, not on faith. A well-maintained 735i is a £5,000–£15,000 classic; a neglected one is a £5,000+ repair bill waiting to happen.

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

→ Compare 735i engine prices before you buy

Don't Guess. Compare.

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

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Buying Checklist

Before you buy a used BMW 735i (or before you commit to an engine replacement), check these:

Cold Start

Listen for rattling, misfires, or blue smoke (N62: valve stem seals; M62: timing chain)

Service History

including which engine era (M30/M62/N62) and confirmed oil-change intervals

Coolant Check (E38)

Any history of coolant loss or cooling system work? (M62's Achilles heel)

Smoke Check

Blue smoke on startup indicates valve stem seal failure (N62)

Valvetronic Operation (E65)

Any hesitation, rough idle, or misfires? (Valvetronic warning)

Oil Consumption

Does it use more than 1L per 1,000 miles? (N62 valve stem seals)

Engine Warning Light

Have codes been read? Any unresolved VANOS, Valvetronic, or cooling system issues?

MOT History

Check for emissions-related failures

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 match Section 1B's Era Map exactly.

M30B35 (3.4L/3.5L Straight-Six)

Years1977–1992

Power197–218 bhp (145–160 kW) @ 5,200–5,700 rpm · 285–310 Nm

2025 Enquiries- (pattern data)

Avg. Recon Cost£2,500–£4,500 [PLACEHOLDER]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M30B35 (3.4L/3.5L Straight-Six)1977–1992197–218 bhp (145–160 kW) @ 5,200–5,700 rpm · 285–310 Nm- (pattern data)£2,500–£4,500 [PLACEHOLDER]

M62B35 (3.5L V8)1996–2001235 bhp (173 kW) @ 5,700 rpm · 345 Nm- (pattern data)£3,500–£6,500 [PLACEHOLDER]

N62B36 (3.6L V8)2001–2008272 bhp (200 kW) @ 6,200 rpm · 360 Nm- (pattern data)£4,500–£8,500 [PLACEHOLDER]

Technical Specs

M30B35 (E23/E32)Displacement: 3,430 cc (later 3,453 cc) · Cylinders: Straight-6, SOHC, 12 valves · Fuel: Bosch Motronic injection

M62B35 (E38)Displacement: 3,498 cc · Cylinders: V8, DOHC, 32 valves · Fuel: Direct injection

N62B36 (E65/E66)Displacement: 3,600 cc · Cylinders: V8, DOHC, 32 valves · Fuel: Direct injection · Valvetronic

→ Compare 735i engine prices for your BMW

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Market Intelligence

Most Common Failure (E23/E32)

Electronics and HVAC systems

the M30 engine itself is bulletproof

Most Common Failure (E38)

Cooling system failures

plastic radiators, expansion tanks, and water pumps

Most Common Failure (E65/E66)

Valve stem seal failure and Valvetronic issues

Average Enquiry Mileage

80,000

–150,000 miles

[PATTERN DATA]

Average Replacement Cost

£3,500

–£6,500 reconditioned, supply only

[PLACEHOLDER - confirm vs cost sheet]

Most Requested Engine Code

M30B35 (E23/E32)

[PATTERN DATA]

Peak Enquiry Season

Winter

cold starts expose cooling system and valve seal issues【PATTERN DATA】

Regional Demand

South East20%

London18%

South West15%

PATTERN DATA

Regional Demand Breakdown

20%South East

18%London

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.

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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