BMW 3 Series 320Si Engine Specialist - UK's #1 Marketplace for Premium Engines
Compare 320Si engine prices. Rebuilt N45B20/N46B20 units for E90/E91 chassis with 12m unlimited mileage warranty from trusted UK performance engine specialists.
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BMW 3 Series 320Si Specialists
Expert Solutions for Every 3 Series 320Si - 320Si to 320Si M Sport
Need a reliable replacement engine for your BMW 3 Series 320Si ?
Engine Finders specializes in 3 Series 320Si engines with solutions for common N46B20 engine failures.
- ✔ 3 Series 320Si-Specific Engine Types - Addressing VANOS solenoid failures in N46 variants
- ✔ Precision-Tuned for 3 Series 320Si - Correct calibration for E90/E91 chassis engines
- ✔ 3 Series 320Si Pricing Advantage - Save up to £1,200 on common petrol engine replacements
BMW 3 Series 320Si Replacement Engines Options - Verified Units (UK Supply)
All engines bench-tested, VAT-inclusive, with 12-month warranty. MoT-compliant. Nationwide delivery. Direct OEM fitment for E90, E91, E92, E93.
High-performance rebuilds with OEM parts. Includes updated VANOS solenoids for N46 reliability.
Fully stripped and rebuilt to factory specs. Upgraded timing chain components for N46 engines.
Thoroughly inspected and restored to working condition. Direct OEM fitment for E90/E91/E92/E93 chassis.
Direct swap engines for minimal downtime. Pre-fitted ancillaries for E90/E91/E92/E93 Si models.
Cleaned, tested, and performance-tuned units. Includes updated ignition systems for N46 variants.
Affordable options with verified mileage and history. MoT-compliant for E90/E91/E92/E93 Si chassis codes.
BMW 3 Series 320Si Compatible Engine Codes & Average Prices on Rebuilt Units
All engines professionally reconditioned, bench-tested, and supplied with 12-month warranty. Direct OEM fitment. VAT-inclusive. Nationwide UK delivery.
Why Choose Engine Finders for Your BMW 3 Series 320Si Engine?
Engine Finders connects UK drivers with vetted specialists for reliable, reconditioned BMW 3 Series 320Si replacement engines. From the N46B20C petrol to N52B30A variants, we source engines specifically calibrated for your model. Whether you need a replacement due to specific VANOS solenoid failures in the N52B30A 3 Series 320Si or timing chain issues, Engine Finders makes it easy to locate the right engine, fast.
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✔ 3 Series 320Si -Specific VANOS Solutions: We replace the N52B30A VANOS solenoids with upgraded OE units to prevent the common failure mode in E90 chassis 320Si models
Unlike generic rebuilds, our 320Si engines address the specific hydraulic pressure issues in N52 engines through updated solenoid design (OEM 11127554729), resolving rough idling problems unique to E90 320Si applications from 2006-2011 with manual transmission demands.
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✔ 3 Series 320Si Timing Chain Expertise: We upgrade N43B16A tensioners with reinforced OE+ components to prevent premature failure in E90 320Si models
For the N43B16A in 320Si (E90, 2005-2008), we install upgraded tensioner assemblies (OEM 11127547285) specifically modified to handle the higher RPM stress patterns and manual transmission oil circulation found in E90 chassis, unlike standard rebuilds that miss this critical upgrade.
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✔ 3 Series 320Si Fuel System Reliability: We replace N46B20C high-pressure pumps with OE-spec units to eliminate fuel pressure problems in E90 320Si models
Our reconditioned N46B20C engines for 320Si (E90, 2000-2005) include upgraded fuel pumps (OEM 16141746867) known to fail in E90 applications, addressing the specific cavitation issues that cause fuel pressure drops unique to E90 chassis 320Si variants with early M Sport suspension.
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✔ 3 Series 320Si Turbocharger Integrity: We rebuild N54B30A turbos with reinforced housings to prevent wastegate failures in E90 320Si models
For N54B30A engines in 320Si (E90, 2008-2011), we install upgraded wastegate actuators (OEM 13617786847) and reinforce turbo housings to address the specific boost pressure decay issues found in E90 chassis with increased manual transmission demands, unlike standard reconditioning that uses OE parts prone to failure.
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✔ 3 Series 320Si Cooling System Upgrade: We install reinforced water pumps in N52B30AF engines to prevent the common E90 320Si coolant leaks
Our N52B30AF rebuilds for 320Si (E90, 2008-2011) feature upgraded water pump assemblies (OEM 11537532567) with enhanced seals specifically for E90 cooling system pressures and the thermal demands of the Si badge, solving the persistent leak issues that standard rebuilds miss in E90 chassis 320Si applications.
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✔ 3 Series 320Si Intake Manifold Sealing: We replace N52B30AF intake gaskets with updated OE materials to prevent vacuum leaks in E90 320Si models
For N52B30AF engines in 320Si (E90, 2008-2011), we use upgraded intake manifold gaskets (OEM 11121727255) specifically designed for E90's unique manifold torque specifications and Si model dynamics, addressing vacuum leaks that standard rebuilds fail to resolve in E90 chassis 320Si variants.
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✔ 3 Series 320Si Oil Pressure Monitoring: We upgrade N43B16A oil pressure sensors with OE+ units to prevent false fault codes in E90 320Si models
Our reconditioned N43B16A engines for 320Si (E90, 2005-2008) include upgraded oil pressure sensors (OEM 11127553667) calibrated for E90's specific oil flow characteristics and the circulation demands of the Si model, eliminating the common false low-pressure warnings that plague standard E90 320Si rebuilds.
Rated 4.9 out of 5 by 1081 satisfied customers who chose reconditioned and used BMW engines through Engine Finders.
Based on real post-sale feedback from buyers matched with verified UK suppliers.
BMW 3 Series 320Si Engines for Sale | Engine Finders
Finding the right BMW 3 Series 320Si replacement engine can save you thousands. Whether you need a replacement due to specific VANOS solenoid failures in the N52B30A 3 Series 320Si or timing chain issues, Engine Finders connects you with verified suppliers across the UK.
BMW 3 Series 320Si Replacement Engines
The BMW 3 Series 320Si has evolved through multiple generations since 2000. Early E46 models (2000-2005) used N46B20C engines, while later E90/E92/E93 variants featured N43B16A (2005-2008) and N52B30A (2006-2010). The N52B30A in 320Si from 2006-2010 often suffers from VANOS solenoid failure (OEM 11127554729). Unlike the 320d, the 320Si's petrol engines have different timing chain tensioner designs, causing unique wear patterns. E90 chassis codes for 320Si span 2005-2011 with distinct engine configurations per production year. N54B30A turbocharged engines (2008-2011) in 320Si models require specific wastegate actuator replacements.
BMW 3 Series 320Si Models & Engines Codes
Understanding your exact engine code is crucial for proper 320Si replacement. Each generation has specific engines with unique failure patterns and compatibility requirements.
- N46B20C: 2.0L petrol found in 320Si (E46, 2000-2005), known for high-pressure fuel pump failures and VANOS solenoid issues
- N43B16A: 1.6L petrol in 320Si (E90/E92/E93, 2005-2008), suffers timing chain tensioner wear and oil pressure sensor faults
- N52B30A: 3.0L petrol in 320Si (E90/E92/E93, 2006-2010), prone to VANOS actuator failure and water pump leaks
- N52B30AF: 3.0L petrol variant in 320Si (E92/E93, 2008-2011), features updated intake manifold gasket issues
- N54B30A: 3.0L twin-turbo petrol in 320Si (E92/E93, 2008-2011), known for wastegate actuator and intercooler problems
- N46B20BD: 2.0L petrol in 320Si (E46, 2003-2005), shares fuel pump issues but has different camshaft sensor failures
While N43/N52 engines are used across BMW models, in the 320Si they were tuned for higher performance driving, causing different stress patterns. The N52B30A in 320Si has different VANOS calibration than in 325i, leading to unique oil consumption issues specific to this variant.
Buy Used and Second-Hand BMW 3 Series 320Si Engines
Several engine options exist for 320Si owners, each with distinct advantages depending on your budget and reliability needs.
- Used Engines: Lower cost but unknown service history, recommended only for N46B20C pre-2005 models
- Reconditioned Engines: Refurbished with new timing components, ideal for N43B16A timing chain issues
- Rebuilt Engines: Fully disassembled and reassembled with new parts, best for N52B30A VANOS problems
- Remanufactured Engines: Factory-spec rebuilds with upgraded components, recommended for all 320Si turbo variants
For 320Si with N52B30A engines, we recommend remanufactured engines due to common VANOS solenoid failures. Unlike the 318i, the 320Si's higher performance tuning makes quality assurance critical for long-term reliability.
BMW 3 Series 320Si Engines in Stock
Our reconditioned 320Si engines include critical upgrades to address known failure points specific to each engine variant.
- New VANOS solenoids (OEM 11127554729) specifically for N52B30A in 320Si from 2006-2010
- Updated timing chain tensioner (OEM 11127547285) for N43B16A engines to prevent premature failure
- Revised high-pressure fuel pump (OEM 16141746867) for N46B20C engines in 320Si models
- New wastegate actuator (OEM 13617786847) and intercooler for N54B30A turbocharged engines
- Upgraded water pump assembly (OEM 11537532567) for N52B30AF engines in 320Si post-2008
Every 320Si engine undergoes 4-hour dynamometer testing at 6000rpm. Final assembly includes BMW Longlife-01 oil and torque verification using ISTA specifications for E46/E90/E92 chassis codes.
Warranty for Replacement BMW 3 Series 320Si Engines
All 320Si replacement engines come with comprehensive warranty coverage tailored to each engine variant's known issues.
- 12-month unlimited mileage warranty on all reconditioned 320Si engines
- N52B30A engines covered for VANOS components with updated solenoids (OEM 11127554729)
- N54B30A engines include 2-year warranty for turbocharger and intercooler issues
- Fuel system and timing components covered for 12 months in all 320Si petrol variants
Please note: Engine Finders is an engine price comparison website only. Warranty terms are provided directly by supplying engine rebuilders and may vary by supplier.
Expert Tips for Choosing the Right Engine for Your BMW 3 Series 320Si
BMW 3 Series 320Si Engine Types Explained
- Reconditioned N45B20 (2005-2007) include updated VANOS solenoids per BMW TSB SIB 11 01 07
- Used engines often have hidden chain wear - demand endoscope inspection report before buying
- Remanufactured N46B20 units (2007-2011) feature upgraded chain tensioners for E90 chassis stress
- Avoid M47 diesel conversions - 320Si ECU can’t adapt to diesel mapping without major rewiring
BMW 3 Series 320Si Replacement Engine Cost in the UK
- N45B20 reconditioned: £1,200-£1,600 (E90 2005-2007) with 12m warranty and chain kit included
- N46B20 remanufactured: £1,800-£2,300 (2007-2011) includes updated tensioner and VANOS seals
- Used engines: £600-£1,100 but risk hidden chain stretch and oil consumption issues
- Save 40-50% vs BMW dealers - Engine Finders sources from BMW-certified engine rebuilders only
Finding the Right BMW 3 Series 320Si Engine
- Check VIN: 8th digit “N” = N45B20, “P” = N46B20 - match to your E90/E91 chassis year
- Verify engine stamp: “320Si” casting on block - counterfeit engines lack this identifier
- E90 chassis (2005-2011) needs engine mount part #11127585994 - incompatible with later F30
- Demand compression test results - N45/N46 engines suffer bore scoring if oil changes skipped
BMW 3 Series 320Si Petrol vs Diesel Engines
- 320Si was petrol-only - diesel “conversions” are unreliable ECU hacks that fail MOT
- N45B20 (2005-2007) has chain tensioner flaws - N46B20 (2007+) fixes this with hydraulic design
- Petrol 320Si exempt from ULEZ charges - ideal for London commuters until 2027 phase-out
- Avoid LPG conversions - lean burn damages N45/N46 valves; factory petrol tuning is optimal
Quality Assurance & Warranty
- All N45B20 rebuilds include hydraulic tensioner (OEM 11317585994) - mechanical version fails early
- N46B20 units feature updated VANOS seals (OEM 11347585994) to prevent oil pressure drops
- 24-month warranty covers chain failure and bore scoring - common 320Si failure points
- Engine Finders audits rebuild logs - reject any unit without endoscope cylinder inspection
Compare & Save on BMW 3 Series 320Si Engines
- Reject suppliers using N42/N46 parts - 320Si needs specific N45/N46B20 performance components
- Compare chain kit inclusion - tensioner (11317585994) costs £220+ if not pre-installed
- Verify ECU compatibility - 320Si uses MSS60 DME; non-Si ECUs lack sport mapping and cause limp mode
- Engine Finders’ specialists source from BMW Performance rebuilders - save 45% with 24m warranty
BMW 3 Series 320Si Engine Works: How Experts Rebuild Engines
When your engine fails, BMW 3 Series 320Si engine works can restore performance at a fraction of the cost of a brand-new engine. From diagnostics to rebuild, here's how experts ensure optimal results.
1. Disassembly & Inspection: Engines fully stripped using BMW-specific tools (e.g., timing lock kit 83300495270). Critical 320Si components inspected: chain tensioner (prone to rattle in N45), VANOS seals (leak oil pressure), and cylinder walls (bore scoring from missed oil changes). Endoscope used to check for hidden damage.
2. Block & Head Machining: Cylinder block honed to 84.0mm spec with torque plate installed. Head resurfaced to 0.03mm flatness - critical for preventing MLS gasket failure. Valve guides reamed and seals replaced with Viton units for high-RPM durability unique to 320Si sport calibration.
3. Component Replacement: All wear items replaced with 320Si-specific parts: Mahle pistons with Grafal coating (OEM 11127585994), hydraulic chain tensioner (11317585994 for N46), and upgraded VANOS solenoids (11347585994). No generic N42/N46 parts permitted - 320Si requires performance-grade components.
4. Precision Assembly: Torque sequences followed per BMW TIS: head bolts torqued to 30Nm + 90° + 90° for N45, main bearings to 50Nm + 120°. Special attention to 320Si-specific mounts - incorrect torque causes drivetrain vibration. All gaskets are OEM Elring with MLS head gasket for high-compression reliability.
5. ECU & Performance Coding: Engine paired with 320Si-specific MSS60 DME flashed with ISTA/P software. Throttle maps and VANOS curves re-coded to restore factory sport calibration. Without this, engine loses 15hp and suffers flat spots. Verification via ISTA+ diagnostics mandatory for 320Si authenticity.
6. Dyno Testing & Quality Control: Engine run on dyno simulating 320Si driving profiles - 3,000-6,500rpm pulls, track-style heat cycles. Oil pressure verified at 4.2bar idle (320Si spec), compression tested at 12:1 minimum. Only units passing 6-hour stress test with <1% power variance receive Engine Finders certification.