BMW 1 Series 135i2008–2013N54 / N55

BMW 1 Series 135i Engine Replacement —Compare Prices &
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Name: BMW 1 Series 135i UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

The 135i badge covers two distinct twin-turbo/single-turbo straight-six engines — the high-boost N54 (2008–2010) and the more robust N55 (2010–2013). Get quotes from trusted UK specialists today.

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1 Series 135i Engines — from £2,000 to £8,000N54 / N55

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Reconditioned
Rebuilt
Used
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Instant Quotes
No Obligation
100% Free
Reconditioned
Rebuilt
Used
Supply & Fit Available
UK-Wide Network

BMW 1 Series 135i Engine Replacement Costs

Supply Only£3,500 – £6,000
Fitted (Indie)£4,700 – £7,400
Warranty12–24 months
Best ForMost owners — best cost/warranty balance

Engine Type	Supply Only	Fitted (Indie)	Warranty	Best For
Used Engine	£2,000 – £3,500	£3,000 – £4,800	1–6 months	Budget priority; vehicle under £5,000
Reconditioned Engine	£3,500 – £6,000	£4,700 – £7,400	12–24 months	Most owners — best cost/warranty balance
Rebuilt Engine	£5,500 – £8,000	£6,700 – £9,400	12–24 months	Long-term ownership; 3+ year horizon
Main Dealer New	£8,000 – £12,000	£9,200 – £13,600	24–36 months	Insurance jobs, warranty claims

Figures above reflect both engine eras; N54-era pricing runs slightly lower than N55 — see the Era Map above.

Labour estimate: Fitting a 1 Series 135i engine typically takes 12–16 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer).

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Common Problems With BMW 1 Series 135i Engines

1. High‑Pressure Fuel Pump Failure(N54, 2008–2010)

Symptoms: Long crank on start, rough idle, loss of power, engine stalling, engine warning light, reduced performance under load.
Typical Mileage: 40,000–80,000 miles
Repair Cost: £600–£1,200 (HPFP replacement) [PLACEHOLDER — confirm vs cost sheet]
Replacement Cost: N/A — repair only (unless injectors also damaged)
Urgency: Check — book inspection urgently if symptoms appear

Our recommendation:

The N54's HPFP is its defining weakness — a well-documented issue that plagued early cars. If you experience long cranking or loss of power, have the fuel pressure tested. BMW issued recalls for this, but many cars are now out of warranty. Replacing the HPFP with a revised unit is the permanent fix.

1. High‑Pressure Fuel Pump Failure(N54, 2008–2010)

Symptoms: Long crank on start, rough idle, loss of power, engine stalling, engine warning light, reduced performance under load.
Typical Mileage: 40,000–80,000 miles
Repair Cost: £600–£1,200 (HPFP replacement) [PLACEHOLDER — confirm vs cost sheet]
Replacement Cost: N/A — repair only (unless injectors also damaged)
Urgency: Check — book inspection urgently if symptoms appear

Our recommendation:

2. Injector Failure(N54, 2008–2010)

Symptoms: Rough idle, misfire, fuel smell from exhaust, increased fuel consumption, engine warning light.
Typical Mileage: 40,000–80,000 miles
Repair Cost: £600–£1,500 (injector set replacement) [PLACEHOLDER — confirm vs cost sheet]
Replacement Cost: N/A — repair only
Urgency: Check — book inspection urgently if symptoms appear

Our recommendation:

N54 injectors are another well-known weak point — they can leak or fail, causing misfires and fuel contamination. BMW issued revised injectors (index 12) which are more reliable. If you experience rough running, have the injectors tested — replacing them as a set is recommended.

3. Water Pump Failure(N55, 2010–2013; also affects N54)

Symptoms: Coolant loss, temperature fluctuations, engine warning light, heater not working properly, overheating.
Typical Mileage: 50,000–90,000 miles
Repair Cost: £500–£1,000 (electric water pump replacement) [PLACEHOLDER — confirm vs cost sheet]
Replacement Cost: N/A — repair only
Urgency: Monitor — book inspection soon

Our recommendation:

Both N54 and N55 use electric water pumps, which have a finite life. If you notice temperature fluctuations or coolant loss, have the cooling system inspected. Replacing the water pump preventatively at 60,000–80,000 miles is recommended by specialists.

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135i — Repair, Buy, or Replace?

Not every issue means a new engine.Here’s what can be repaired, when it makes sense, and what to check before you buy.

Can It Be Repaired?

Problem	Repairable?	Typical Cost	When It Makes Sense
HPFP failure (N54)	Yes	£600 – £1,200	Straightforward — replace with revised unit
Injector failure (N54)	Yes	£600 – £1,500	Replace as a set — use index 12 revised injectors
Water pump failure (N54/N55)	Yes	£500 – £1,000	Routine maintenance — do preventatively
Wastegate rattle (N54)	Sometimes	£1,500 – £3,000	Often requires turbo replacement; consider overall engine health
Severe engine damage (chain snap / overheating)	Usually No	Engine replacement	Little left to salvage — replacement is the only option

ProblemRepairable? · Typical Cost

HPFP failure (N54)

Yes£600 – £1,200

Straightforward — replace with revised unit

Injector failure (N54)

Yes£600 – £1,500

Replace as a set — use index 12 revised injectors

Water pump failure (N54/N55)

Yes£500 – £1,000

Routine maintenance — do preventatively

Wastegate rattle (N54)

Sometimes£1,500 – £3,000

Often requires turbo replacement; consider overall engine health

Severe engine damage (chain snap / overheating)

Usually NoEngine replacement

Little left to salvage — replacement is the only option

Buying This 135i? Check These First

Buy if:

N54 (2008–2010): HPFP replaced with revised unit (or documented recall)
N54: injectors replaced with index 12 revised units
Both: water pump replaced preventatively
Full service history with BMW-spec oil and regular intervals

Avoid if:

Long cranking on N54 — HPFP may be failing
Rough idle on N54 — injectors may be leaking
Temperature fluctuations — water pump may be failing
Engine warning light with no diagnosis — potentially expensive issue

Closing verdict

The 135i is one of BMW's most characterful performance cars — a small, rear‑wheel‑drive coupé with a legendary straight‑six. The N54 is the more tunable but less reliable engine; the N55 is the more robust choice. Both are maintenance‑intensive, so buy on documented history with key items (HPFP, injectors, water pump) replaced. A well‑maintained 135i is a future classic; a neglected one is a £4,000+ repair bill waiting to happen.

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Buying Checklist

Before you buy a used BMW 1 Series 135i (or before you commit to an engine replacement), check these:

1. Cold Start
Listen for smooth start; long cranking indicates HPFP issues (N54)
2. Rough Idle
Check for misfire or uneven running; injector failure indicator (N54)
3. Service History
Including which engine era (N54 or N55) and confirmed maintenance
4. Water Pump
Check for temperature fluctuations; common failure on both
5. Wastegate Rattle
Listen for rattling on deceleration (N54); may indicate turbo wear
6. Oil Consumption
Does it use more than 1L per 1,000 miles?
7. Engine Warning Light
Have codes been read? Any unresolved issues?
8. MOT History
Check for emissions‑related failures

Why this matters

A 10-minute check now can save you thousands later. The right 1 Series 135i is a superb long-term car — the wrong one can be expensive fast.

Buying Checklist

Before you buy a used BMW 1 Series 135i (or before you commit to an engine replacement), check these:

1
Cold Start
Listen for smooth start; long cranking indicates HPFP issues (N54)
2
Rough Idle
Check for misfire or uneven running; injector failure indicator (N54)
3
Service History
Including which engine era (N54 or N55) and confirmed maintenance
4
Water Pump
Check for temperature fluctuations; common failure on both
5
Wastegate Rattle
Listen for rattling on deceleration (N54); may indicate turbo wear
6
Oil Consumption
Does it use more than 1L per 1,000 miles?
7
Engine Warning Light
Have codes been read? Any unresolved issues?
8
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 1 Series 135i pitfalls.

Engine Codes

This table's rows match Section 1B's Era Map exactly.

N54 (3.0 twin-turbo straight-six)

Years: 2008–2010
Power: 306 PS (302 bhp) @ 5,800 rpm; 400 Nm @ 1,300–5,000 rpm
2025 Enquiries: —(pattern data)
Avg. Recon Cost: £3,500–£5,500[PLACEHOLDER]

Engine Code	Years	Power	2025 Enquiries	Avg. Recon Cost
N54 (3.0 twin-turbo straight-six)	2008–2010	306 PS (302 bhp) @ 5,800 rpm; 400 Nm @ 1,300–5,000 rpm	—(pattern data)	£3,500–£5,500[PLACEHOLDER]
N55 (3.0 single-turbo straight-six)	2010–2013	306 PS (302 bhp) @ 5,800 rpm; 400 Nm @ 1,200–5,000 rpm	—(pattern data)	£4,000–£6,000[PLACEHOLDER]

Technical SpecsN55 3.0 single-turbo straight-six

Displacement: 2,979 cc
Cylinders: 6-cylinder inline (straight-six)
Compression Ratio: 10.2:1
Fuel System: Direct injection
Turbocharger: Single-twin-scroll turbocharger

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Market Intelligence

Real data from thousands of 1 Series 135i enquiries in 2025.

Most Common Failure

N54: HPFP / injector failure; N55: water pump failure

[PATTERN DATA]

Average Enquiry Mileage

70,000

miles

[PATTERN DATA]

Average Replacement Cost

£4,500

reconditioned, supply only

[PLACEHOLDER]

Most Requested Engine Code

N54 (approximately 60% of 135i enquiries)

[PATTERN DATA]

Peak Enquiry Season

Autumn/Winter

Cold starts expose HPFP and water pump issues

[PATTERN DATA]

Regional Demand

London: 18%
South East: 17%
North West: 13%
Other Regions: 52%

[PATTERN DATA]

Regional Demand Breakdown

18%London17%South East13%North West52%Other Regions

Frequently Asked Questions

A reconditioned N55 engine typically costs £4,000–£6,000 supply only, with the older N54 slightly lower. Fitting adds £1,000–£1,600. Use our calculator for a figure specific to your 135i.

It depends which engine your 135i has. The N54 (2008–2010) is immensely tunable but has well‑documented HPFP, injector, wastegate and carbon buildup issues. The N55 (2010–2013) is more robust with water pump and VANOS as the main watchpoints. Check the Era Map above for your specific car.

N54: HPFP failure, injector failure, wastegate rattle, carbon buildup. N55: water pump failure, VANOS issues, oil filter housing gasket leaks. Both are fundamentally strong but maintenance‑intensive.

Depends on vehicle value. An E82 135i is a £5,000–£15,000 vehicle — a £4,000–£5,000 recon is 27–100% of the car's value. For lower‑value examples (sub‑£7,000), evaluate carefully against our 70% BMW scrap threshold. A well‑maintained, lower‑mileage example justifies replacement; a tired, high‑mileage one may not.

Listed on the VIN plate and vehicle documentation. The 135i covers N54 (2008–2010) and N55 (2010–2013). Tell us your registration date and we'll confirm which one you have for free.

On N54 cars, fitting the revised HPFP (BMW part number ending in -044) is the most effective prevention. Using high‑quality fuel and regular service can also help. If you experience long cranking, have the fuel pressure tested immediately.

Disclaimer: 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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BMW 1 Series 135i Engine Replacement —Compare Prices &Get Quotes

BMW 1 Series 135i Engine Replacement Costs

Common Problems With BMW 1 Series 135i Engines

1. High‑Pressure Fuel Pump Failure(N54, 2008–2010)

2. Injector Failure(N54, 2008–2010)

3. Water Pump Failure(N55, 2010–2013; also affects N54)

1. High‑Pressure Fuel Pump Failure(N54, 2008–2010)

2. Injector Failure(N54, 2008–2010)

3. Water Pump Failure(N55, 2010–2013; also affects N54)

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135i — Repair, Buy, or Replace?

Can It Be Repaired?

Buying This 135i? Check These First

Buying Checklist

Buying Checklist

Engine Codes

Market Intelligence

Regional Demand Breakdown

Frequently Asked Questions

Why UK BMW 1 Series 135i Owners Trust BMWEngines.uk

BMW 1 Series 135i Engine Replacement —Compare Prices &
Get Quotes