How much does a BMW Z4 sDrive28i / 30i engine replacement cost in the UK?

A reconditioned Z4 sDrive28i (N20) engine typically costs £3,500–£6,500 supply only, while a reconditioned sDrive30i (B48) engine costs £4,500–£8,500. Fitting adds £800–£1,500 at independent specialist rates. Use our calculator for a figure specific to your car.

Is the BMW Z4 sDrive28i / 30i engine reliable?

It depends on which generation you're asking about. The N20 (E89 sDrive28i, 2011–2016) has a well-documented timing chain tensioner issue - pre-2015 cars are the highest risk, and the water pump recall is a safety-critical item. The B48 (G29 sDrive30i, 2019+) is generally considered reliable, but oil and coolant leaks are common. Across both, oil-change discipline is everything.

What are the common problems with the BMW Z4 sDrive28i / 30i?

N20 timing chain wear (E89), N20 water pump recall (E89 - fire risk), B48 oil leaks from valve cover and oil filter housing (G29), B48 timing chain guide fragility (G29), and B48 coolant leaks (G29). See the Era Map above for generation-specific advice.

Is it worth replacing a BMW Z4 sDrive28i / 30i engine, or should I scrap the car?

Depends on vehicle value. Against a well-kept E89 Z4 (values £6,000–£15,000+), a £4,000–£5,000 recon is 30–60% of the car's value - borderline but often worth it for a good example. Against a £20,000–£40,000 G29, a £5,000–£6,000 recon is 15–25% - worth it. The BMW scrap threshold of 70% means evaluating the whole vehicle and its condition before committing.

How do I find my BMW Z4 sDrive28i / 30i engine code?

Listed on the VIN plate and vehicle documentation. As a rule of thumb: E89 sDrive28i (2011–2016) = N20B20A; G29 sDrive30i (2019–present) = B48B20. Tell us your registration date and we'll confirm it for free.

Can I repair the N20 timing chain, or does it need replacement?

Yes - if caught early. A preventative chain, tensioner and guide replacement costs £800–£2,000. BMW extended the warranty on N20 timing chains to 7 years/70,000 miles in some markets. However, if the chain snaps, a full engine replacement (£3,500–£6,500) is usually required. At the first sign of cold-start rattle, book an inspection immediately.

BMW Z4 sDrive28i / 30i2011–presentN20 / B48 2.0 Turbo

BMW Z4 sDrive28i / 30i Engine Replacement — Compare Prices & Get Quotes

Name: BMW Z4 sDrive28i / 30i UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

Get quotes today from trusted UK BMW Z4 sDrive28i and sDrive30i specialists. Compare reconditioned, rebuilt and used N20 and B48 2.0-litre turbocharged engines - supply & fit available nationwide for BMW's iconic roadster.

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BMW Z4 sDrive28i / 30i Engines - from £2,000 to £8,500Common codes: N20B20, B48B20

BMW Z4 sDrive28i / 30i Engines - from £2,000 to £8,500· Common codes: N20B20, B48B20

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The Z4 sDrive28i / 30i THROUGH TIME - Era Map

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

Era Note

The turbocharged four-cylinder that replaced the straight-six - N20 timing chain tensioner is the defining weak point; pre-2015 cars are highest risk

GenerationYearsEngine CodeReliabilityRecon CostEra Note

Z4 E89 (sDrive28i) BMW 320d Z4 E89 (sDrive28i)

2011–2016N20B20 (2.0L 4-cyl turbo, 245 bhp)★★★☆☆ [NEWLY ASSIGNED - see Data Note]£3,500–£6,500 [PLACEHOLDER - confirm vs cost sheet]The turbocharged four-cylinder that replaced the straight-six - N20 timing chain tensioner is the defining weak point; pre-2015 cars are highest risk

Z4 G29 (sDrive30i) BMW 320d Z4 G29 (sDrive30i)

2019–presentB48B20 (2.0L 4-cyl turbo, 255–258 bhp)★★★★☆ [NEWLY ASSIGNED - see Data Note]£4,500–£8,500 [PLACEHOLDER - confirm vs cost sheet]Modern B48 - 255–258 bhp, 295 lb-ft; significantly improved reliability but coolant leaks 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 Z4 sDrive28i / 30i Engine Replacement Costs

Supply Only£3,500–£6,500

Fitted (Indie)£4,500–£7,800

Warranty12–24 months

Best ForMost owners - best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£2,000–£3,500£2,800–£4,8001–6 monthsBudget priority; vehicle under £8,000

Reconditioned Engine£3,500–£6,500£4,500–£7,80012–24 monthsMost owners - best cost/warranty balance

Rebuilt Engine£5,000–£8,500£6,200–£10,00012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer New£7,000–£10,500£8,500–£12,50024–36 monthsInsurance jobs, warranty claims

Figures above reflect the current Z4 sDrive30i B48 era. Older generations: see the Era Map above for E89/N20-specific pricing. A replacement engine for a BMW can cost anywhere from £1,000 to over £5,000, with typical reconditioned engine costs ranging from £1,200–£2,200 supply only.

Labour estimate: Fitting a Z4 engine typically takes 8–12 hours at £75–£110/hr (independent) or £130–£180/hr (London/SE dealer). The Z4's engine bay is reasonably accessible. [PLACEHOLDER - confirm vs cost sheet]

→ Compare Z4 sDrive28i / 30i engine prices from UK specialists

Common Problems With BMW 320d Engines

1. N20 Timing Chain & Tensioner Failure (E89 sDrive28i, pre-2015)

Symptoms: Rattling or whining noise from the engine on cold start, metallic clattering, engine warning light, loss of power, potential engine failure if chain skips or snaps.

Typical mileage: 60,000–100,000 miles - the timing chain can develop slack, causing rapid wear on sprockets and plastic guides.

Repair cost: £800–£2,000 (preventative chain, tensioner and guide replacement)【PLACEHOLDER】

Replacement cost: £3,500–£6,500 (if chain snaps and valves meet pistons)【PLACEHOLDER】

🔴 Immediate - if you hear rattle, book an inspection today

Our recommendation:

The N20's timing chain tensioner is the defining weak point of this engine generation. A failing tensioner can lead to a rattling noise from the engine, and if it completely fails, it can cause catastrophic engine damage. BMW extended the warranty on N20 timing chains to 7 years/70,000 miles in some markets due to the severity of the issue. Pre-2015 cars are the highest risk. A cold-start rattle is the early warning sign - ignore it and you risk piston-valve contact and a full engine replacement. At the first sign of rattle, get it inspected immediately.

1. N20 Timing Chain & Tensioner Failure (E89 sDrive28i, pre-2015)

Symptoms: Rattling or whining noise from the engine on cold start, metallic clattering, engine warning light, loss of power, potential engine failure if chain skips or snaps.

Typical mileage: 60,000–100,000 miles - the timing chain can develop slack, causing rapid wear on sprockets and plastic guides.

Repair cost: £800–£2,000 (preventative chain, tensioner and guide replacement)【PLACEHOLDER】

Replacement cost: £3,500–£6,500 (if chain snaps and valves meet pistons)【PLACEHOLDER】

🔴 Immediate - if you hear rattle, book an inspection today

Our recommendation:

2. N20 Water Pump & Electrical Short-Circuit Recall (E89 sDrive28i)

Symptoms: Engine warning light, coolant loss, potential engine fire risk, water pump electrical connector failure.

Typical mileage: Any mileage - recall affecting 2012–2016 Z4 sDrive28i models

Repair cost: £0 (if recall applies) - £400–£900 (if out of warranty)【PLACEHOLDER】

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

🔴 Immediate - check recall status immediately; can cause engine fire

Our recommendation:

BMW recalled more than 720,000 vehicles, including the 2012–2016 Z4 sDrive28i, due to a fire risk involving the N20 engine. The N20 engine could short-circuit at the water pump's electrical plug connector due to accumulating blow-by fluid from the positive crankcase ventilation system. If your Z4 sDrive28i hasn't had this recall work completed, check your vehicle's recall status immediately. This is a safety-critical item - do not delay.

3. B48 Oil Leaks (G29 sDrive30i - Valve Cover & Oil Filter Housing)

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

Typical mileage: 40,000–80,000 miles

Repair cost: £400–£900 (valve cover gasket or oil filter housing gasket replacement)【PLACEHOLDER】

Replacement cost: N/A - repair only

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

Our recommendation:

Oil leaks are one of the most common complaints with the B48 engine, particularly from the valve cover gasket and oil filter housing. Over time, the gaskets can wear out, leading to leaks that can affect engine performance. If you notice oil spots under the car or a burning smell, have it inspected promptly. Valve cover gasket and oil filter housing gaskets can get brittle over time.

4. B48 Timing Chain Guide Fragility (G29 sDrive30i)

Symptoms: Rattling noise from the engine, potential timing chain jump, engine warning light, loss of power.

Typical mileage: 60,000 km (approximately 37,000 miles)

Repair cost: £800–£2,000 (timing chain guide replacement)【PLACEHOLDER】

Replacement cost: £4,500–£8,500 (if chain jumps and valves meet pistons)【PLACEHOLDER】

🔴 Immediate - if you hear rattle, book an inspection today

Our recommendation:

The B48 engine is generally considered reliable, but the timing chain guide can become fragile around 60,000 km, with a risk of chain jumping and engine damage. If you hear a rattling noise from the engine, have the timing system inspected immediately. Regular oil changes with the correct BMW-approved oil are the best prevention.

5. B48 Coolant Leaks (G29 sDrive30i)

Symptoms: Low coolant warning, coolant loss with no visible external leak, sweet smell from engine bay, temperature fluctuations, overheating.

Typical mileage: 40,000–80,000 miles

Repair cost: £400–£1,200 (coolant system diagnosis and repair)【PLACEHOLDER】

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

🟠 Check - book inspection urgently if coolant loss is detected

Our recommendation:

Coolant leaks are a common issue on modern BMW engines, with the heater management module and oil filter housing being weak points that can lead to overheating and expensive repairs. The EGR radiator can also suffer from coolant leaks. If you notice coolant loss or temperature fluctuations, have the system pressure-tested immediately. Proactive replacement of known weak coolant hoses at 60,000 miles is recommended.

Weighing Your Options?

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BMW Z4 sDrive28i / 30i - 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 Z4 sDrive28i / 30i - 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 SenseN20 timing chain rattle (preventative)✅ Yes£800–£2,000Catch it early - far cheaper than engine replacementN20 water pump recall✅ Yes£0 (recall) / £400–£900Recall work is free; out-of-warranty repair is still viableB48 oil leaks (valve cover/OFH)✅ Yes£400–£900Affordable preventative maintenanceB48 timing chain guide wear✅ Yes£800–£2,000Catch it early - far cheaper than engine replacementB48 coolant leaks✅ Yes£400–£1,200Diagnosis and repair is straightforward; catch it before overheatingSnapped timing chain (N20)❌ Usually NoEngine replacementPiston-valve contact means little is left to repair

Buying This Z4 sDrive28i / 30i? Check These First

Buy If

Full service history with oil changes at 8,000–10,000 mile intervals
E89 (2011–2016): timing chain tensioner replaced or inspected (post-2015 cars are lower risk)
E89 (2011–2016): water pump recall completed (check with BMW)
G29 (2019+): no coolant loss and cooling system in good order
No cold-start rattle on any generation

Avoid If

No proof of regular oil changes - these engines are unforgiving of neglect
E89 with cold-start rattle - timing chain work is imminent and expensive
E89 with no proof of water pump recall - potential fire risk
G29 with coolant loss with no diagnosis - cooling system repairs can be complex
Any engine warning light without diagnosis - these engines can hide expensive faults

Closing Verdict

The BMW Z4 sDrive28i and sDrive30i represent two generations of BMW's iconic roadster. The E89 sDrive28i introduced BMW's new turbocharged four-cylinder, replacing the beloved straight-six - it offers strong performance but the N20 timing chain tensioner is a critical weak point, and the water pump recall is a safety-critical item. The G29 sDrive30i is a significant step forward in reliability, with the B48 engine offering 255–258 bhp and 295 lb-ft of torque, but coolant and oil leaks are the key watchpoints. Across both generations, one rule applies: oil-change discipline is everything. BMW's extended service intervals are widely considered inadequate - treat your Z4 to 8,000–10,000 mile oil changes and it will reward you with hundreds of thousands of miles of driving pleasure.

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

→ Compare Z4 sDrive28i / 30i engine prices before you buy

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Buying Checklist

Before you buy a used BMW Z4 sDrive28i or sDrive30i (or before you commit to an engine replacement), check these:

Cold Start

Listen for rattle lasting more than 1–2 seconds (N20 timing chain warning; B48 timing chain guide warning)

Service History

Including which engine era (N20/B48) and confirmed oil-change discipline (8k–10k miles max)

Water Pump Recall (E89)

Check recall status; this is a safety-critical item on the N20

Oil Leaks (G29)

Check for oil around the valve cover and oil filter housing

Coolant Level

Check cold and hot; any loss indicates potential cooling system issues

Engine Temperature

Any fluctuations? Cooling system may be failing

Engine Warning Light

Have codes been read? Timing, cooling, or oil leak codes are most common

MOT History

Check for emissions failures (often related to fuel system or PCV issues)

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.

N20B20A (E89 sDrive28i)

Years2011–2016

Power245 bhp (180 kW) @ 5,000 rpm · 350 Nm @ 1,250 rpm

2025 Enquiries- (pattern data)【PATTERN DATA】

Avg. Recon Cost£3,500–£6,500【PLACEHOLDER - confirm vs cost sheet】

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

N20B20A (E89 sDrive28i)2011–2016245 bhp (180 kW) @ 5,000 rpm · 350 Nm @ 1,250 rpm- (pattern data)【PATTERN DATA】£3,500–£6,500【PLACEHOLDER - confirm vs cost sheet】

B48B20 (G29 sDrive30i)2019–present255–258 bhp (190 kW) · 295 lb-ft (400 Nm)- (pattern data)【PATTERN DATA】£4,500–£8,500【PLACEHOLDER - confirm vs cost sheet】

Technical Specs

B48B20 - G29 sDrive30i

Displacement1,997cc

Cylinders4-cylinder inline, 16 valves, DOHC

Bore x Stroke84.0mm x 90.1mm

Compression Ratio10.0:1

Fuel SystemHigh-pressure direct injection

TurbochargerSingle twin-scroll turbocharger

Valve ControlVALVETRONIC and Double VANOS

Displacement1,998cc

Cylinders4-cylinder inline, DOHC

Fuel SystemDirect injection

TurbochargerSingle twin-scroll turbocharger

→ Compare Z4 sDrive28i / 30i engine prices for your BMW

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Market Intelligence

Most Common Failure

N20 timing chain wear (E89) and B48 oil/coolant leaks (G29)

45%

of Z4-related enquiries cite chain, oil, or cooling concerns【PATTERN DATA】

Average Enquiry Mileage

50,000

–80,000 miles【PATTERN DATA】

Average Replacement Cost

£5,000

reconditioned, supply only【PLACEHOLDER】

Most Requested Engine Code

N20B20A

E89-era Z4 sDrive28i is the most common Z4 on UK roads【PATTERN DATA】

Peak Enquiry Season

Spring and summer

convertible season exposes cooling and oil leak issues【PATTERN DATA】

Regional Demand

South East22%

London18%

South West (14%)【PATTERN DATA】

Regional Demand Breakdown

22%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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