BMW Z4 sDrive18i / sDrive20i Engine Replacement — Compare Prices & Get Quotes
Get quotes today from trusted UK BMW Z4 specialists. Compare reconditioned, rebuilt and used 2.0-litre turbocharged petrol engines - N20 and B48 variants across the E89 and G29 generations - supply & fit available nationwide.
The Z4 sDrive18i / sDrive20i THROUGH TIME - Era Map
Four generations. Four eras. One guide to reliability, costs and what really matters.
Era Note
2.0L turbo four - 156–184 bhp; timing chain guide failure is the critical weakness; pre-2015 units most at risk
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.
BMW Z4 sDrive18i / sDrive20i Engine Replacement Costs
Figures above reflect current Z4 replacement costs. The B48 variant typically sits at the higher end of the range. See the Era Map above for generation-specific pricing.
Labour estimate: Fitting a Z4 engine typically takes 10–14 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer).
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Z4 sDrive18i / sDrive20i - 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?
Buying This Z4 sDrive18i / sDrive20i? Check These First
Buy If
- G29 (2018+) with the B48 engine (improved timing chain design)
- Post-2015 E89 with documented timing chain guide replacement
- Full service history with regular oil changes (critical for chain longevity)
- No cold-start rattling (timing chain health)
- No oil leaks around the oil filter housing (B48 - belt damage risk)
Avoid If
- Pre-2015 E89 with cold-start rattle and no chain history - assume it's overdue
- No service history - the N20 is unforgiving of neglect
- Oil leaks around the oil filter housing (belt damage risk - B48)
- Overheating history or unexplained coolant loss - cooling system may be compromised
- VANOS system failure symptoms - loss of power, rough idle
Closing Verdict
The Z4 sDrive18i / sDrive20i is BMW's entry-level turbocharged petrol roadster - powered by a 2.0-litre four-cylinder engine across two generations. The E89 (2009–2016) has the N20 - with well-known timing chain guide issues, particularly pre-2015. The G29 (2018+) has the B48 - a significant improvement with the timing chain design resolved. Common B48 issues are oil leaks, coolant leaks, and a starter motor recall on early models. With typical Z4 values ranging from £8,000 (E89) to £25,000+ (G29), an engine replacement is a significant investment - the B48-engined G29 is the safer choice.
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Buying Checklist
Before you buy a used BMW Z4 sDrive18i / sDrive20i (or before you commit to an engine replacement), check these:
Cold Start
Listen for rattling (N20 timing chain warning) - see the map above
Service History
Including which engine era (N20 or B48) and oil-change discipline
Timing Chain
For E89 N20: check for any chain work or cold-start rattle; pre-2015 most at risk
Oil Leaks
Check around oil filter housing (B48 - belt damage risk)
Coolant Level
Check reservoir when cold; any low or loss may indicate water pump or thermostat issues
VANOS Health
Test acceleration; any loss of power or sluggish response may indicate VANOS solenoid wear
Engine Warning Light
Have codes read; unresolved issues may indicate timing, cooling or sensor problems
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.
BMW 320d Engine Codes
This table's rows match Section 1B's Era Map exactly.
N20B20A
Technical Specs
B48B20A - G29 generation→ Compare Z4 sDrive18i / sDrive20i engine prices for your Z4
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Market Intelligence
Most Common Failure
N20 timing chain guide failure (E89 pre-2015)
the defining issue of the earlier Z4
Average Enquiry Mileage
50,000
–70,000 miles
[PATTERN DATA]
Average Replacement Cost
£4,000
–£5,000 reconditioned, supply only
[PLACEHOLDER]
Most Requested Engine Code
N20B20A / B48B20A
[PATTERN DATA]
Peak Enquiry Season
Winter
cold starts expose timing chain wear
[PATTERN DATA]
Regional Demand
PATTERN DATA
Regional Demand Breakdown
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 condition, 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 Z4 sDrive18i / sDrive20i Owners Trust BMWEngines.uk
Trusted Z4 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real Z4 sDrive18i and sDrive20i owners, as part of the Engine Finders network, across every generation - N20 and B48 - covering the E89 and G29 chassis.
Compare Z4 Engine Replacement Companies
see prices, warranty terms and supply & fit options side-by-side before you commit. We cover the 2.0-litre turbocharged petrol specifically, with specialists who understand the N20 timing chain vulnerabilities, B48 oil leak tendencies, and the unique requirements of the Z4 roadster.
UK Engine Replacement Services for Z4
supply-only or full supply & fit available nationwide, covering every generation of this badge since 2009, with a 12-month warranty as standard across our network.
Find the best BMW Z4 sDrive18i / sDrive20i engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and get your roadster back on the road with confidence.
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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