BMW 4 Series 430i Engine ReplacementCompare Prices & Get Quotes

A BMW 4 Series 430i engine replacement typically costs between £3,800 and £6,000 for a reconditioned unit, with rebuilt engines ranging from £5,000 to £8,000. Used engines start from around £2,000. These prices are supply-only - fitting adds 10-14 hours of labour at specialist rates (£650-£910).

• Reconditioned B48B20O0/O1: £3,800-£6,000
• Rebuilt B48B20O0/O1: £5,000-£8,000
• Used B48B20O0/O1: £2,000-£3,800

The B48 engine in the 430i is generally reliable, but there are some well-documented issues to be aware of. The most common are coolant system leaks (oil filter housing and coolant flange), timing chain tensioner wear, and carbon buildup on intake valves due to direct injection.

• Coolant leaks: plastic components crack over time; upgrade to aluminium parts where possible
• Timing chain: less problematic than N20 but still requires regular oil changes and inspection
• Carbon buildup: walnut blasting recommended at 60,000-80,000 miles

It depends on your car's value and condition. For a 2016-2020 BMW 4 Series 430i worth £8,000-£22,000, a rebuilt engine at £5,000-£8,000 is a significant investment but often worthwhile if the car is otherwise in good condition. For cars under £8,000, carefully evaluate whether a repair or used engine makes more financial sense.

• Cars worth £8,000-£12,000: consider a used or reconditioned engine
• Cars worth £12,000+: a rebuilt engine with warranty is usually the best long-term value
• Always factor in the car's overall condition - not just the engine

Both the 430i and 420i use the same B48 2.0-litre turbocharged petrol engine, but the 430i is tuned for higher output. The 430i produces 245-252bhp, while the 420i produces approximately 181-184bhp. The engines share the same basic architecture, but the 430i features different engine calibration and turbocharger mapping.

• 430i: higher-output petrol, 245-252bhp, 0-62 in ~5.9 seconds
• 420i: entry-level petrol, ~181bhp, 0-62 in ~7.3 seconds
• Both use the same B48 engine family - many components are interchangeable

A BMW 4 Series 430i engine replacement typically takes 2-3 days for a specialist workshop to complete, assuming the replacement engine is already in stock. This includes removal of the old engine, fitting the replacement, and full system testing.

• Supply only: 1-2 days for delivery
• Supply & fit: 2-3 days in the workshop
• Some specialists offer same-day dispatch on qualifying orders

Every rebuilt and reconditioned engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty. Some suppliers offer extended warranties of up to 24 months on certain engine types. Always confirm exact terms with your chosen supplier before purchase.

• 12-month unlimited-mileage: minimum standard
• 24-month options: available on many premium rebuilds
• Warranty covers: manufacturing defects and component failure

The BMW 4 Series 430i with the B48 engine is generally considered reliable, particularly compared to the earlier N20 engine it replaced. The B48 is a robust, well-engineered unit when properly maintained. However, like any modern engine, it requires diligent maintenance - particularly regular oil changes and cooling system inspections.

• B48 is significantly more reliable than N20
• Regular oil changes (8,000-10,000 miles) are critical
• Cooling system components should be inspected regularly