BMW 3 Series E93Convertible2006–2013
Every engine fitted to the E93 convertible — from the naturally aspirated N52 sixes to the twin-turbo N54 and the post-2010 N55 switch, alongside the full range of diesel fours and sixes that define UK ownership.
Real UK replacement costs, honest failure data, and the convertible-specific labour access that sets this body apart from the E90 saloon.
Backed by 256+ real UK E9X enquiries in 2025 [BMW-VERIFIED].
Engine Database
Every engine fitted to the E93 convertible specifically — including the mid-cycle N54-to-N55 switch and the M57-to-N57 diesel transition that most guides miss.
Overview
The E93 is the convertible body of BMW's fifth-generation 3 Series, launched in December 2006 as the final variant of the E9X family. It introduced a folding metal hardtop — a first for the 3 Series convertible — replacing the fabric roof of the E46 convertible.
A significant March 2010 facelift (LCI) brought more than cosmetic changes: it replaced the N54 twin-turbo petrol with the single-turbo N55 and the M57 diesel six with the all-new N57, splitting this generation's ownership story into two distinct mechanical eras under one body code. The E93 is also approximately 200 kg heavier than the E92 coupé due to the folding roof mechanism, affecting performance and fuel economy.
Key Facts
Market Intelligence
The E9X family generated 256 real UK engine enquiries in 2025 [BMW-VERIFIED], with E93-specific enquiries concentrated on the N47 diesel four and N54/N55 petrol six as these cars exit warranty and major component replacement decisions become critical.
04Best & Worst Engines
Best Diesel Overall
M57D30 (pre-LCI, 2007–2010)
“Cast-iron block, no rear-mounted timing chain to worry about, and a documented reputation for exceeding 300,000 miles with routine servicing. Thermostat housings and swirl flaps are its only real demands. In the E93, it's the diesel you can buy without anxiety.”
Who it's for: buyers who want the last of BMW's bulletproof diesel-six era.
Best Petrol Overall
N52B30 (pre-LCI, 2006–2010)
“Naturally aspirated, no HPFP, no turbo — just smooth, linear six-cylinder power with VANOS/Valvetronic as the only real wear items. In the heavier E93 convertible, the N52's 272 bhp is perfectly matched to the chassis.”
Who it's for: enthusiasts who want simplicity over outright pace. (Model-wide: B58B30 in the G20 sets the modern benchmark — see G20 →)
Highest Risk
N47D20A/C (2008–2013, no chain history)
“The rear-mounted timing chain is this generation's defining diesel risk — cold-start rattle is the warning, and a snapped chain means full replacement. The E93's weight and automatic transmission options don't help; the N47 is the single biggest ownership risk on the convertible diesel range.”
Who it's for: only buyers with documented chain-replacement history.
Most Expensive Failure
N54B30 HPFP & Injector Failure
“High-pressure fuel pump failure leads to long cranks and limp mode on the twin-turbo 335i; injector issues often follow. In the E93 convertible, the additional body weight means the N54 works harder, potentially accelerating component wear.”
Who it's for: 335i buyers with deep pockets and full service history.
Best Value
M57D30 330d (pre-LCI)
“Older than the N57, but proven, cheaper to insure on higher mileage, and free of the rear-chain question entirely. In the E93, the 231 bhp six-cylinder diesel offers effortless waftability with the roof down.”
Who it's for: buyers who want six-cylinder torque without the modern diesel's caveats.
Most Overlooked
N57D30 (post-LCI, single-turbo only)
“Genuinely improved over the M57 on economy and refinement, and — critically for this specific generation — E93 never received the later twin-turbo N57 variants whose crank-bearing risk affects F30/G30-era cars. E93's N57 is the single-turbo version only.”
Who it's for: buyers who want a modern diesel-six without the twin-turbo risk profile that shows up in later cars.
Best Diesel Overall
M57D30
(pre-LCI, 2007–2010)
“Cast-iron block, no rear-mounted timing chain to worry about, and a documented reputation for exceeding 300,000 miles with routine servicing. Thermostat housings and swirl flaps are its only real demands. In the E93, it's the diesel you can buy without anxiety.”
Who it's for: buyers who want the last of BMW's bulletproof diesel-six era.
Best Petrol Overall
N52B30
(pre-LCI, 2006–2010)
“Naturally aspirated, no HPFP, no turbo — just smooth, linear six-cylinder power with VANOS/Valvetronic as the only real wear items. In the heavier E93 convertible, the N52's 272 bhp is perfectly matched to the chassis.”
Who it's for: enthusiasts who want simplicity over outright pace. (Model-wide: B58B30 in the G20 sets the modern benchmark — see G20 →)
Highest Risk
N47D20A/C
(2008–2013, no chain history)
“The rear-mounted timing chain is this generation's defining diesel risk — cold-start rattle is the warning, and a snapped chain means full replacement. The E93's weight and automatic transmission options don't help; the N47 is the single biggest ownership risk on the convertible diesel range.”
Who it's for: only buyers with documented chain-replacement history.
Most Expensive Failure
N54B30
HPFP & Injector Failure
“High-pressure fuel pump failure leads to long cranks and limp mode on the twin-turbo 335i; injector issues often follow. In the E93 convertible, the additional body weight means the N54 works harder, potentially accelerating component wear.”
Who it's for: 335i buyers with deep pockets and full service history.
Best Value
M57D30
330d (pre-LCI)
“Older than the N57, but proven, cheaper to insure on higher mileage, and free of the rear-chain question entirely. In the E93, the 231 bhp six-cylinder diesel offers effortless waftability with the roof down.”
Who it's for: buyers who want six-cylinder torque without the modern diesel's caveats.
Most Overlooked
N57D30 (post-LCI, single-turbo only)
“Genuinely improved over the M57 on economy and refinement, and — critically for this specific generation — E93 never received the later twin-turbo N57 variants whose crank-bearing risk affects F30/G30-era cars. E93's N57 is the single-turbo version only.”
Who it's for: buyers who want a modern diesel-six without the twin-turbo risk profile that shows up in later cars.
Engine
Typical Mileage
Common Major Failure
Repair Cost (Specialist)
Replacement Cost (Recon)
Ownership Verdict
Solid Choice -reliable, naturally aspiratedBest Petrol -272 bhp, no turbo worries
Most Expensive -fast, but costly to maintainSolid Choice -improved over N54
Risk vs Reward -budget for chain historyBest Diesel -cast-iron, bulletproofSolid Choice -improved economy, single-turbo onlyEngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership VerdictSolid Choice -reliable, naturally aspiratedBest Petrol -272 bhp, no turbo worriesMost Expensive -fast, but costly to maintainSolid Choice -improved over N54Risk vs Reward -budget for chain historyBest Diesel -cast-iron, bulletproofSolid Choice -improved economy, single-turbo only
The E93 rule
A £3,200–£5,500 N47 recon against a £5,000–£15,000 E93 sits at 21–110% of the car's value. On a sub-£6,000 E93, that brushes our 70% BMW threshold -we'll honestly tell you to walk away. Against a well-kept £12,000+ low-mileage example, the same recon drops to a routine 27–46% -a repair decision, not a financial one. Value the car first. Remember: E93 convertibles command a premium over E90 saloons, so the threshold calculation differs.
N47D20A/C
Timing Chain Stretch
Affected models:
E93 320d (2008–2013).
Typical failure mileage:
60,000–100,000 miles.
Root cause:
The rear-mounted timing chain receives the last oil feed and is tensioned by a plastic guide that degrades over time -cold-start rattle for 1–2 seconds is the classic early warning. This affects the entire N47 family in the E93.
Tiered Cost Table
Preventative (Repair)
Dealer
Specialist
£1,800–£2,500
£650–£1,800
Catastrophic (Replacement)
Dealer
Specialist
£6,000–£8,000
£3,200–£5,500
Our Recommendation
At the first sign of cold-start rattle on any N47-powered E93, get the chain inspected immediately -a £650–£1,800 preventative repair is dramatically cheaper than the £3,200–£5,500 replacement that follows if ignored. On an E93 worth under £6,000, this decision alone determines whether the car stays economically viable.
N54B30
HPFP & Injector Failure
Affected models:
E93 335i (2006–2010, pre-LCI).
Typical failure mileage:
30,000–80,000 miles.
Root cause:
The high-pressure fuel pump's internal wear leads to fuel pressure loss, hard starting, and eventual engine damage if ignored; injector issues frequently follow. The E93's additional 200 kg weight over the E92 means the N54 works harder, potentially accelerating wear.
Tiered Cost Table
Preventative (Repair)
Dealer
Specialist
£1,200–£1,800
£800–£1,500
Catastrophic (Replacement)
Dealer
Specialist
£7,000–£9,000
£4,500–£7,500
Our Recommendation
If your E93 335i has no documented HPFP history, treat it as overdue preventative maintenance -£800–£1,500 now is far cheaper than the £4,500+ replacement that follows a lean-running failure. This is the single most important maintenance item on the N54.
M57D30
Thermostat & Swirl Flap Wear
Affected models:
E93 325d, 330d (2007–2010, pre-LCI).
Typical failure mileage:
80,000–130,000 miles.
Root cause:
Plastic thermostat housings crack with age and heat cycling; swirl flap linkages in the intake wear and can, in rare cases, detach into the cylinder. The E93's weight doesn't affect this directly, but the engine works harder in the heavier convertible.
Tiered Cost Table
Preventative (Repair)
Dealer
Specialist
£500–£800
£200–£400
Catastrophic (Replacement)
Dealer
Specialist
£900–£1,400
£400–£700
Our Recommendation
This is cheap insurance on the E93's most dependable diesel engine -a £200–£400 thermostat and swirl flap check every service is trivial against the M57's otherwise bulletproof reputation. In the E93, it's the smartest preventative spend you can make.
Folding
Hardtop Mechanism Wear
Affected models:
All E93 convertibles (2006–2013).
Typical failure mileage:
80,000+ miles (age-related).
Root cause:
Not an engine failure, but the most common non-engine enquiry on this generation -the folding metal hardtop's hydraulic system and microswitches can fail with age, leading to roof operation faults. The E93's roof is heavy and complex, and repairs can be expensive.
Tiered Cost Table
Preventative (Repair)
Dealer
Specialist
£600–£1,200
£300–£700
Catastrophic (Replacement)
Dealer
Specialist
£2,500–£4,000
£1,200–£2,500
Our Recommendation
Have the roof mechanism inspected at every major service on any E93 over 80,000 miles -a £300–£700 preventative service is dramatically cheaper than the £1,200–£2,500 full overhaul that follows if ignored. This is the single most common reason an otherwise sound E93 fails an inspection.
VariantEngine Code
Used (Supply)
Reconditioned (Supply)
Rebuilt (Supply)
Labour Hours
Scope note: All variants listed are E93 convertible only. E90 saloon, E91 Touring and E92 Coupé share most of these engines but are covered on their own Generation Pages, since fitment and labour access vary by body style -particularly in the convertible, where additional structural bracing can complicate engine access. The E93 M3 is covered separately on its own generation page.
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£3,900
reconditioned, supply only
[BMW‑QUOTE]
Most Common Failures
Live FeedBMW 320d E93
N47
ManchesterCold‑start rattle5
enquiries
Updated MonthlyBMW 330d E93
M57
LeedsThermostat/performance check3
enquiries
Updated MonthlyBMW 335i E93
N54
BirminghamHPFP failure2
enquiries
Updated MonthlyMost Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£3,900
reconditioned, supply only
[BMW‑QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£3,900
reconditioned, supply only
[BMW‑QUOTE]
Most Common Failures
Scope note: All variants listed are E93 convertible only. E90 saloon, E91 Touring and E92 Coupé share most of these engines but are covered on their own Generation Pages, since fitment and labour access vary by body style -particularly in the convertible, where additional structural bracing can complicate engine access. The E93 M3 is covered separately on its own generation page.
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£3,900
reconditioned, supply only
[BMW‑QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£3,900
reconditioned, supply only
[BMW‑QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£3,900
reconditioned, supply only
[BMW‑QUOTE]
Most Common Failures
Live FeedBMW 320d E93
N47
ManchesterCold‑start rattle5
enquiries
BMW 330d E93
M57
LeedsThermostat/performance check3
enquiries
BMW 335i E93
N54
BirminghamHPFP failure2
enquiries
Updated MonthlyTrusted E93 Engine Suppliers
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UK Engine Replacement Services for E93
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