BMW Z4 20i Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK BMW Z4 20i engine specialists. Compare prices on reconditioned, rebuilt and used N46 and N20 engines - supply & fit available nationwide for your E85 or E89 roadster.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
From £1,300 to £3,600
Used from £800 · Reconditioned from £1,300 · Common codes: N46B20, N46B20B, N20B20A
From £800
Tested, bare/short engine
From £1,300
Rod bearings addressed, tested
From quote
Upgraded bearings, full teardown, revised valvetrain
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3 Simple Steps3 Simple Stepsto Finding the Best BMW Z4 20i Replacement Engineto Finding the Best BMW Z4 20i Replacement Engine
Most replacements completed within 3-5 days.
Variant HistoryBMW Z4 20i - Engine History & Specs at a Glance
The BMW Z4 20i spans two distinct generations with two very different four-cylinder engines. The E85 Z4 20i (2005-2008) used the naturally aspirated N46B20 inline-four, while the E89 Z4 sDrive20i (2011-2016) introduced the turbocharged N20B20A with BMW TwinPower Turbo technology. The 20i badge represented the entry point to Z4 ownership across both generations, offering accessible performance with four-cylinder efficiency.
Variant HistoryBMW Z4 20i - Engine History & Specs at a Glance
The BMW Z4 20i spans two distinct generations with two very different four-cylinder engines. The E85 Z4 20i (2005-2008) used the naturally aspirated N46B20 inline-four, while the E89 Z4 sDrive20i (2011-2016) introduced the turbocharged N20B20A with BMW TwinPower Turbo technology. The 20i badge represented the entry point to Z4 ownership across both generations, offering accessible performance with four-cylinder efficiency.
BMW Z4 20i
Fuel TypePetrol
Engine Size Range2.0L (1995-1997cc)
Power Output Range150-184hp across the variant's historyEngine History Timeline
March 2005 - E85 Z4 20i introduced with N46B20 2.0L naturally aspirated four-cylinder 150hp (110kW)
2008 - N46B20 remains the sole engine for the E85 Z4 20i throughout production
September 2011 - E89 Z4 sDrive20i launched with N20B20A 2.0L TwinPower Turbo four-cylinder 184hp (135kW)
2016 - N20B20A powers the E89 Z4 sDrive20i with 270Nm torque from 1,250rpm
E89 Z4 production ends; the 20i badge retired until the G29 generation
Key Specs Snapshot
Fuel TypePetrolEngine Size Range2.0L (1995-1997cc)Power Output Range150-184hp across the variant's historyYears Produced2005-2008 (E85), 2011-2016 (E89)Every engine fitted to the BMW Z4 20i is covered below, with UK rebuilt pricing and known failure points - from the E85 N46 to the E89 N20 turbo.
BMW Z4 20i Engine Codes - Specifications & Replacement CostBMW Z4 20i Engine Codes - Specifications & Replacement Cost
2.0L Naturally Aspirated Four-Cylinder Petrol (2005-2008)
Power Output150hp (110kW)Displacement1995ccYears Fitted2005-2008
Compatible Trim Levels
- 2.0i
- 2.0i Sport
- 2.0i SE (E85 Roadster)
Find your exact engine code, specs and UK replacement cost guide.
Used
Tested, ready-to-fit engine
£800-£1,600
Reconditioned
Addressed known issues, tested
£1,300-£2,400
Rebuilt
Full teardown, upgraded internals
£1,800-£2,800
Common Failure
The N46B20 is known for several age-related issues. Oil leaks from the valve cover gasket and oil filter housing are extremely common. Timing chain tensioner failure can cause a rattling noise and, if ignored, lead to serious engine damage. Cooling system failures (water pump and thermostat) can cause overheating. VANOS problems can lead to rough idle and performance issues. Camshaft wear due to poor oil maintenance has also been reported.
The BMW Z4 20i is powered by two very different four-cylinder engines depending on the generation. The N46 (E85, 2005-2008) is a naturally aspirated unit with age-related oil leak and timing chain concerns, while the N20 (E89, 2011-2016) is a turbocharged engine with a well-documented timing chain guide failure. Below we break down the most common failures on both Z4 20i engines, what you'll pay at a dealer versus a specialist, and when replacement is the only sensible answer. Every rebuilt engine supplied through EnginesMarket includes upgraded components designed to address the original failure point - plus a minimum 12-month unlimited mileage warranty.
Why BMW Z4 sDrive20i Engines Fail Catastrophically
Affected Vehicles
BMW Z4 sDrive20i (N20B20A, 2011-2016, particularly pre-2015)
Typical Failure Mileage
60,000-100,000 miles
Root Cause
The N20 timing chain guides are made of plastic that becomes brittle and breaks under heat cycling and chain oscillations. When the guides fail, the chain can slip or break, causing piston-to-valve contact and total engine destruction. Symptoms include a rattling noise on cold start and a "tractor-like" sound from the engine.
Why It Happens
The N20 timing chain guides are made of plastic that becomes brittle and breaks under heat cycling and chain oscillations. When the guides fail, the chain can slip or break, causing piston-to-valve contact and total engine destruction. Symptoms include a rattling noise on cold start and a "tractor-like" sound from the engine.
Dealer (parts + labour)
£1,500-£2,500
Specialist (parts + labour)
£1,200-£1,800
What it involves
Replace timing chain, guides, tensioner, and oil pump drive chain module
Suitability
Recommended before failure; prevents catastrophic engine damage
1 - 2 daysDealer (parts + labour)
£6,000-£9,000
Specialist (parts + labour)
£2,200-£3,600
What it involves
Supply & fit rebuilt N20B20A with upgraded timing components, bench tested, 12-month warranty
Suitability
Required if chain has snapped or caused valve/piston damage
1 - 2 daysAll prices are indicative UK market ranges based on current UK specialist supplier data.| Repair Tier | Dealer (Parts + Labour) | Specialist (Parts + Labour) | What It Involves | Suitability | Estimated Time |
|---|---|---|---|---|---|
 Preventative - Timing Chain & Oil Pump Drive Replacement Minor | £1,500-£2,500 | £1,200-£1,800 | Replace timing chain, guides, tensioner, and oil pump drive chain module | Recommended before failure; prevents catastrophic engine damage | 1 - 2 days |
 Full Replacement - Rebuilt/Reconditioned Engine Best Value | £6,000-£9,000 | £2,200-£3,600 | Supply & fit rebuilt N20B20A with upgraded timing components, bench tested, 12-month warranty | Required if chain has snapped or caused valve/piston damage | 1 - 2 days |
Vehicle Value Check
Vehicle Value Check
A typical BMW Z4 sDrive20i (E89, 2011-2016) in fair condition is worth £6,000-£14,000 depending on mileage and specification. A preventative timing chain replacement at specialist rates (£1,200-£1,800) is excellent value on any Z4 sDrive20i. If the chain has snapped and the engine is destroyed, a £2,200-£3,600 rebuilt engine with warranty is a sound investment on a car worth over £8,000.
Our Recommendation
Our Recommendation
The N20 timing chain is the single biggest risk on the E89 Z4 sDrive20i. If you hear a rattling noise on cold start, do not drive the car - have it inspected immediately. Preventative chain replacement at a specialist costs significantly less than a full engine replacement. On any N20-powered Z4 approaching 70,000 miles without documented chain work, this is essential preventative maintenance.
Don't Let Engine Failure Write Off Your BMW Z4 20i
A failed N46 or N20 engine doesn't have to mean the end of the road for your Z4 20i. Whether you're facing N20 timing chain failure, N46 tensioner issues, or fuel system problems, EnginesMarket connects you with trusted UK BMW Z4 20i specialists who supply rebuilt engines with upgraded components specifically designed to address the original failure point. Every engine comes with a minimum 12-month unlimited mileage warranty, nationwide delivery, and supply & fit options across the UK. Compare prices today - and get your roadster back on the road without paying the main dealer premium.
Compare rebuilt N20B20A BMW Z4 sDrive20i engine prices
12-Month Minimum
UK Specialists Vetted
Best Price GuidanceImportant Information
Important Information
All prices are indicative UK market ranges based on historical quote data and repair requests from our network of engine specialists. Dealer pricing is estimated based on published main dealer labour rates and genuine OEM parts pricing. Specialist pricing reflects actual quote data from EnginesMarket's UK network. Actual costs vary depending on damage severity, vehicle condition, variant, and workshop location within the UK. Use our free comparison tool to get tailored quotes for your specific BMW Z4 20i. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited mileage warranty - always confirm exact terms with your chosen supplier.
BMW Z4 20i Engine ReplacementFrequently Asked Questions
Question 1How much does a BMW Z4 20i engine replacement cost in the UK-
A BMW Z4 20i engine replacement typically costs £1,300-£3,600 supply-only for rebuilt N46 or N20 units, or £2,500-£5,500 fitted by a specialist.
- Used N46B20 engines: £800-£1,600 depending on mileage and condition
- Used N20B20A engines: £1,000-£2,200
- Reconditioned N46/N20 units: £1,300-£2,800 with 12-month warranty
- Rebuilt N46/N20 engines: £1,800-£3,600 with upgraded components
- Professional fitting adds £800-£1,500 depending on workshop rates
Question 2Does the BMW Z4 sDrive20i N20 engine have timing chain problems-
Yes - the N20B20A engine in the E89 Z4 sDrive20i is known for timing chain guide failure. The plastic guides can break, causing chain slack and catastrophic engine damage. This is particularly prevalent on engines produced before 2015. Symptoms include a rattling noise on cold start and a "tractor-like" sound from the engine. If you hear these sounds, do not drive the car - have it inspected immediately. Preventative chain replacement is far cheaper than a full engine replacement.
-> Compare rebuilt N20B20A BMW Z4 sDrive20i engine pricesQuestion 3Is the BMW Z4 E85 2.0i N46 engine reliable-
The N46B20 is generally reliable when properly maintained, but it has age-related issues. The most common problems are oil leaks from the valve cover gasket and oil filter housing, timing chain tensioner wear, and cooling system failures. Regular oil changes using the correct specification oil and prompt attention to leaks are essential to N46 longevity. The N46 is not as problematic as the N20's timing chain issue, but it requires proactive maintenance.
-> Find a reconditioned BMW Z4 20i N46B20 engineQuestion 4What are the signs of N20 timing chain failure on a BMW Z4 sDrive20i-
The most common signs are a rattling noise on cold start that may diminish as the engine warms, a "tractor-like" sound from the engine, and in advanced cases, the engine management light illuminating with camshaft correlation codes. If you notice any of these symptoms on your Z4 sDrive20i, do not drive the car - have the timing chain inspected immediately. Ignoring the rattle can lead to complete engine destruction.
-> Get quotes for N20B20A timing chain repair for BMW Z4 sDrive20iQuestion 5Is it worth replacing the engine on a high-mileage BMW Z4 20i-
For an E89 Z4 sDrive20i worth £6,000-£14,000, a £2,200-£3,600 rebuilt N20B20A engine can make financial sense if the body, gearbox and interior are sound. For an E85 Z4 2.0i worth £3,000-£6,000, carefully evaluate whether a rebuilt engine is financially sensible - for a car in excellent condition, the investment can be justified. A rebuilt engine with warranty offers peace of mind that a high-mileage used unit cannot match.
-> Check BMW Z4 20i engine replacement value for your specific model yearQuestion 6What is the difference between the BMW Z4 20i E85 and E89 engines-
The E85 Z4 20i (2005-2008) uses the N46B20 naturally aspirated 2.0-litre four-cylinder producing 150hp. The E89 Z4 sDrive20i (2011-2016) uses the N20B20A turbocharged 2.0-litre four-cylinder producing 184hp. They are completely different engine families - the N20 is turbocharged with direct injection, while the N46 is naturally aspirated with port injection. When ordering a replacement engine, ensure you match the correct engine code to your Z4 20i's generation.
-> Find a code-matched BMW Z4 20i replacement engine - enter your reg aboveWhy Choose UsCompare BMW Z4 20iEngine PricesToday
150+ N46 and N20 engines supplied through our network
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Comparing quotes for your BMW Z4 20i engine replacement is completely free and carries no obligation. Enter your registration above, tell us your N46B20 or N20B20A engine code, and we'll connect you with trusted UK specialists who can supply or supply & fit the right engine for your Z4 20i - whether you have an E85 or E89 generation. All backed by a minimum 12-month unlimited mileage warranty.
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