BMW B58 Engine for Sale | OEM 3.0L Turbocharged Inline-6 (340i, M340i, GR Supra)

Description

Engine Background

The BMW B58 is widely regarded as BMW’s best modern turbocharged inline-six engine and one of the strongest turbocharged engines produced by any manufacturer in its displacement class. Introduced in 2015 as the replacement for the N55, it has been named to the Ward’s World 10 Best Engines list five times and has earned enthusiast praise as “the modern 2JZ” for its combination of factory reliability and extraordinary tuning potential on stock internals.

Two engineering decisions made the B58 fundamentally different from the N55 it replaced. First, a closed-deck block design. Unlike the N55’s open-deck construction where the cylinder walls have gaps in the water jacket, the B58 has solid material surrounding the cylinder walls throughout. This dramatically reduces cylinder bore distortion under boost and heat, improving both reliability and the engine’s ability to handle high boost pressure. Second, a forged steel crankshaft and drop-forged cracked connecting rods, components that are meaningfully stronger than the N55’s comparable hardware and have been documented to survive 600 to 700 horsepower on stock internals.

The B58TU1 technical update introduced in 2018 to 2019 added a larger turbocharger, revised cylinder head with improved combustion chambers, a higher-pressure fuel injection system (350 bar versus the Gen 1’s 200 bar), and split the B58 into ML (335 hp, middle output) and OL (382 hp, high output) variants. The OL variant powers the M340i, M240i, Z4 M40i, and Toyota GR Supra 3.0, the same engine architecture used in multiple brands simultaneously.

When Replacement Becomes Necessary

• Coolant loss without visible external leak, cracked plastic expansion tank (common on higher-mileage B58 units) or water pump failure
• Oil leaks at valve cover gasket or oil filter housing, the two most common B58 external oil leak points
• Rough idle or misfires, carbon buildup on intake valves from direct injection, particularly on high-mileage examples. Carbon buildup requires walnut blasting to clean.
• PCV system fault codes or oil mist in intake, PCV valve built into the valve cover can fail causing crankcase pressure buildup
• VANOS fault codes or rough running, VANOS solenoid wear on high-mileage units or those with extended oil change intervals
• Turbo wastegate rattle at idle, more common on tuned engines running higher boost, audible as a faint rattling at idle

Known Issues We Document Before Shipping

• Carbon buildup on intake valves, inherent to direct injection B58 engines: direct injection sprays fuel directly into the cylinders, bypassing the intake valves. This means the intake valves accumulate carbon deposits from the PCV system without fuel washing them clean (as port injection does). At 50,000 to 60,000 miles most B58 engines benefit from walnut blasting to clean the intake valves. Symptoms include rough idle, hesitation, and reduced response. This is a maintenance item, not a defect.
• Valve cover gasket leak: the valve cover gasket on the B58 seeps with age, typically becoming evident after 60,000 to 80,000 miles. The leak is rarely catastrophic but should be addressed at engine installation as good practice. The integrated PCV valve in the valve cover should be inspected and replaced if degraded.
• Cooling system known weak points: plastic expansion tank (cracks with age) and electric water pump (electronic failure mode on higher-mileage units). The cooling system is generally more durable than the M54 generation but still benefits from a complete refresh at installation.
• PCV system: the integrated PCV valve in the valve cover can fail, causing crankcase pressure buildup and oil mist in the intake. Symptoms include rough idle and oil consumption. PCV refresh at installation is good practice.
• Generation differences: Gen 1 B58B30M0 (2015 to 2018) and B58TU1 (2018 to 2019 onward) have different turbochargers, fuel injection pressure, and ECU calibrations. Cross-installing requires harness, ECU, and supporting hardware matching. We document generation on every order.

B58 Variants and Application Differences

Critical buyer information for matching the engine to your chassis:

What Ships and What Does Not

Direct-Fit Vehicle Applications

Used OEM Versus Specialist Rebuild

For a 340i, M340i, M240i, Z4 M40i, GR Supra 3.0, or other B58-equipped vehicle with engine failure, used OEM is the most accessible path given the B58’s factory reliability and the cost of specialist rebuilds. For tuners targeting 500-plus horsepower from a B58 platform, the stock internals are widely reported to survive 600 to 700 hp, so the focus is typically on bolt-on supporting hardware (intercooler, downpipe, fueling, tune) rather than internal engine work. Specialist B58 rebuilds for high-power applications typically run $8,500 to $14,000-plus from established BMW tuning shops.

Inspection Workflow

• External condition assessed at all accessible areas
• Generation confirmed: B58B30M0 (Gen 1) or B58TU1 (ML or OL)
• Donor application identified: BMW 340i, M340i, M240i, Z4 M40i, or Toyota GR Supra
• Valve cover gasket area inspected for seepage
• Oil filter housing gasket area inspected for seepage
• Cooling system components externally inspected: expansion tank, water pump area
• VANOS solenoid connector condition externally assessed
• PCV valve area externally inspected
• Turbocharger external condition assessed

Pre-Purchase Buyer Notes

• Plan a complete cooling system refresh at installation: expansion tank, water pump, thermostat, coolant flush. The B58 cooling system is more durable than older BMW engines but still benefits from preventive refresh at install.
• Refresh valve cover gasket and PCV at installation: integrated components in the valve cover. Refreshing while the engine is out is cheap insurance against post-install rough idle and oil consumption.
• Plan walnut blasting for high-mileage units: direct injection engines accumulate carbon on intake valves over time. At 50,000-plus miles, walnut blasting is good practice. Specialist BMW shops offer this service.
• Use BMW-specification oil at 5,000-mile intervals maximum: 5W-30 LL-01 specification. The factory 10,000-mile interval is widely considered too long for the B58’s direct injection and turbocharger.
• For tuning, plan supporting modifications: a tuned B58 producing 500-plus hp benefits from upgraded intercooler, downpipe, fueling, and a custom tune. Stock internals handle the power but supporting hardware needs upgrade for sustained reliability.

Why Buy From Part Nests

• Generation confirmed: B58B30M0 (Gen 1) or B58TU1 (ML or OL) documented before payment
• Donor application identified: BMW or Toyota GR Supra source disclosed
• Valve cover gasket and PCV valve condition externally assessed
• Cooling system condition externally inspected
• VANOS solenoid condition externally assessed
• Turbocharger external condition noted
• No core return required
• Free freight delivery to every state
• 15 day replacement warranty against internal defects
• Call (240) 306-7051 to speak with someone who knows B58 Gen 1 versus B58TU1 differences, BMW versus Toyota GR Supra donor variations, and direct injection carbon buildup service planning