BMW X3 35i (F25) engine: which one, problems and replacement

The BMW X3 35i in the second X3 generation (F25, built 2010–2017) was built with one engine, the N55B30: a 3.0 L petrol inline-6 with 306 hp.

Below you will find how to identify the engine in your X3 35i, the faults to look for, current prices for a replacement and the swap options that make sense.

• Generation: second X3, 2010–2017
• Body styles: F25 (SAV)
• Engines: N55B30
• Output: 306 hp
• Replacement engines in stock: 393 from 2.207,00 €

Which engine is in your X3 35i?

N55B30 in the X3 35i

The N55B30 was used in the F25 X3 35i, built 2009–2017. It is a 3.0 L turbocharged petrol inline-6 with 306 hp and 400 Nm.

Reading the code: N marks an N-series code, the generation of BMW engines introduced from 2001; 55 is the family number; B stands for petrol (from the German Benzin); 30 is the capacity in decilitres, so 3.0 litres.

X3 35i engines by model year

The X3 35i kept the same engine for the whole F25 run, which makes ordering simple: any unit with the same code fits, subject to the gearbox, drive type and sump.

Other cars with the same engine as the X3 35i

A replacement engine does not have to come from another X3 35i. These models left the factory with the same engine code, so a unit from any of them is a candidate donor once the sump, mounts and ancillaries are matched to your car.

N55B30: BMW F30 335i, BMW F10 535i, BMW F20 M135i, BMW F22 M235i, BMW E70 X5 35i.

How to confirm your engine code

The X3 35i only used the N55B30, but the exact version can still change with the build date, gearbox and market. Send us the last seven characters of the VIN and we read the engine code from BMW's records, or look for the code stamped on the block. How to find your BMW engine code.

Known X3 35i engine problems

The N55B30 in the X3 35i shares the known weak points of the N55 family. Full N55 guide.

Oil filter housing gasket. Leaks oil down the engine and onto belts.

Valve cover gasket. The plastic cover leaks and its built-in PCV can fail.

Electric water pump and thermostat. Fails around 100,000 km.

Charge pipe. The plastic charge pipe cracks under boost.

Wastegate rattle. The wastegate wears on high-mileage engines.

Oil pan gasket. Leaks on higher-mileage engines.

Symptoms to watch for on the X3 35i

Rattle for a few seconds after a cold start. The classic sign of a weak timing chain tensioner or stretched chain. It must be checked quickly: a chain that jumps a tooth can bend valves.

Whistle, loss of boost or limp mode. A split charge pipe, a sticking wastegate or worn turbo bearings. Check the pipes first, then the turbo shaft for play.

Poor low-down torque and uneven idle. VANOS seals or solenoids. The engine may run well at high revs but feel flat and lumpy at low speed.

Limp mode with a Valvetronic fault. The Valvetronic motor, its eccentric shaft sensor or the wiring. The engine runs on a reduced throttle until it is repaired.

Long cranking before the engine starts. On direct-injection engines, a weak high-pressure fuel pump or leaking injector lets pressure drop when the engine is off.

Looking after the X3 35i engine

• Oil: 5W-30 or 0W-30 BMW Longlife-01, about 6.5 litres.
• Service interval: Oil every 10,000 to 15,000 km.
• Timing drive: Timing chain at the front.
• Workshop notes: Replace the oil filter housing gasket and valve cover gasket before installing a used N55.

Buying a used engine for the X3 35i: checklist

1. Warranty terms in writing. Read what the warranty covers, how long it runs and what fitting conditions apply. Most warranties require a qualified workshop, new fluids and filters, and replacement of the cooling parts that caused the original failure.
2. Sump, oil pickup and drive variants. Rear-drive, xDrive and front-drive cars can use different sumps, oil pickups and engine mounts even with the same engine code. Check that the sump matches your subframe and front axle.
3. Confirm the exact engine code. Read the code stamped on the block and compare it with the code for your car. Send us the last seven characters of the VIN and we confirm the match before anything is paid.
4. Why your old engine failed. Before fitting a replacement, find out why the original failed. An overheating radiator, a blocked intercooler or a failed turbo can destroy a second engine if they are not fixed.
5. Ask how the donor car was damaged. Most good used engines come from cars with body damage. A front-end impact can crack sensors, the timing cover or the sump; a rear or side impact usually leaves the engine untouched. The yard records the damage on each unit.
6. Turbocharger shaft play and oil. Rotate the compressor wheel by hand. A small amount of side play is normal; in-and-out play or wheel contact with the housing is not. Oil pooled in the intake or intercooler pipes points to worn seals.
7. Timing chain noise. Listen for a rattle at the front of the engine for the first seconds after a cold start. On an engine that cannot be run, look at the chain guides through the oil filler or with the valve cover off.
8. VANOS operation. Rough idle, a rattle from the front of the head and a loss of torque at low revs point to VANOS seals or solenoids. These are serviceable parts and are easier to renew with the engine out.
9. Double VANOS units and solenoids. Ask for the adaptation values or fault history if the engine was running. Solenoids are inexpensive and are often replaced as a matter of course on a used engine.
10. Valvetronic motor and eccentric shaft sensor. The Valvetronic motor and its sensor cause limp-mode faults when they fail. Inspect the connector and the seal around the motor for oil.
11. Injectors and high-pressure fuel pump. Direct-injection engines rely on high-pressure pumps and precise injectors. Ask whether the injectors are original or updated and whether there were fuel pressure faults.
12. Electric water pump. This engine uses an electric water pump. It fails without warning and needs a diagnostic bleeding routine when it is replaced or the system is refilled.

BMW X3 35i replacement engine cost

Across 393 X3 35i engine units in our stock today, prices start at 2.207,00 € and reach 5.826,00 €. The median — the price in the middle of the range — is 4.035,00 €.

Prices depend on the exact version, the donor's mileage, how complete the engine is and the demand for that code. Higher-output versions, low mileage and dressed engines with turbo, injectors and ancillaries cost more; long blocks and higher mileage cost less.

X3 35i engine prices by model year

Engines from 2005–2009 have a median of 4.563,00 €, while units from 2015–2019 sit at 4.043,00 €. Newer engines usually cost more because they come from younger donor cars with lower mileage and later updates.

X3 35i engine prices by mileage

Mileage matters less than history on a well-maintained BMW engine, but it is a useful guide. A low-mileage unit from a younger car gives you more life for a modest premium.

2 of these come from F25 donor cars, priced from 5.372,00 € to 5.522,00 €. An engine from the same body is the most direct swap because the sump, mounts and ancillaries already match.

On top of the engine, budget for the workshop's labour and the parts that are best replaced while the engine is out: engine mounts, the rear main seal, cooling parts, a clutch or converter seal, fluids and filters.

Replacement engines in stock for the X3 35i

These X3 35i units are in our Hamburg yard right now. Each listing shows real photographs of the engine you receive, its mileage and what is fitted.

BMW F15 X5 xDrive35i N55B30 Engine 2011, 74,900 km4.147,00 €BMW F15 X5 xDrive35i N55B30 Engine 2010, 54,700 km4.102,00 €BMW E92 335i N55B30 Engine 2014, 155,700 km3.973,00 €BMW F15 X5 xDrive35i N55B30 Engine 2016, 18,000 km3.282,00 €BMW E92 335i N55B30 Engine 2012, 139,100 km3.613,00 €BMW F32 435i N55B30 Engine 2015, 71,900 km4.350,00 €BMW E92 335i N55B30 Engine 2010, 165,400 km3.465,00 €BMW F15 X5 xDrive35i N55B30 Engine 2011, 125,500 km4.058,00 €BMW E92 335i N55B30 Engine 2016, 194,800 km3.927,00 €BMW F15 X5 xDrive35i N55B30 Engine 2014, 149,400 km4.257,00 €BMW F30 335i N55B30 Engine 2013, 70,400 km3.568,00 €BMW F15 X5 xDrive35i N55B30 Engine 2013, 20,700 km3.346,00 €

BMW F15 X5 xDrive35i N55B30 Engine 2011, 74,900 km — 4.147,00 €, reduced from 5.000,00 €. It comes from a 2011 donor car with 74,900 km, and 14 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW F15 X5 xDrive35i N55B30 Engine 2010, 54,700 km — 4.102,00 €, reduced from 5.150,00 €. It comes from a 2010 donor car with 54,700 km, and 16 units are available. We can confirm fitment against your VIN the same day.

BMW E92 335i N55B30 Engine 2014, 155,700 km — 3.973,00 €, reduced from 5.250,00 €. It comes from a 2014 donor car with 155,700 km, and 17 units are available. We can confirm fitment against your VIN the same day.

BMW F15 X5 xDrive35i N55B30 Engine 2016, 18,000 km — 3.282,00 €, reduced from 4.250,00 €. It comes from a 2016 donor car with 18,000 km, and 17 units are available. The listing shows every side of the engine and the fitted parts.

BMW E92 335i N55B30 Engine 2012, 139,100 km — 3.613,00 €, reduced from 4.300,00 €. It comes from a 2012 donor car with 139,100 km, and 24 units are available. The listing shows every side of the engine and the fitted parts.

BMW F32 435i N55B30 Engine 2015, 71,900 km — 4.350,00 €, reduced from 5.300,00 €. It comes from a 2015 donor car with 71,900 km, and 7 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW E92 335i N55B30 Engine 2010, 165,400 km — 3.465,00 €, reduced from 4.700,00 €. It comes from a 2010 donor car with 165,400 km, and 20 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW F15 X5 xDrive35i N55B30 Engine 2011, 125,500 km — 4.058,00 €, reduced from 4.900,00 €. It comes from a 2011 donor car with 125,500 km, and 10 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW E92 335i N55B30 Engine 2016, 194,800 km — 3.927,00 €, reduced from 5.200,00 €. It comes from a 2016 donor car with 194,800 km, and 7 units are available. The listing shows every side of the engine and the fitted parts.

BMW F15 X5 xDrive35i N55B30 Engine 2014, 149,400 km — 4.257,00 €, reduced from 5.400,00 €. It comes from a 2014 donor car with 149,400 km, and 14 units are available. The listing shows every side of the engine and the fitted parts.

BMW F30 335i N55B30 Engine 2013, 70,400 km — 3.568,00 €, reduced from 4.650,00 €. It comes from a 2013 donor car with 70,400 km, and 24 units are available. The listing shows every side of the engine and the fitted parts.

BMW F15 X5 xDrive35i N55B30 Engine 2013, 20,700 km — 3.346,00 €, reduced from 4.000,00 €. It comes from a 2013 donor car with 20,700 km, and 9 units are available. Ask the desk for compression figures or extra photographs before you order.

Will it fit my X3 35i?

Will the N55B30 fit my BMW F25 X3 35i?

The N55B30 is the original engine for the BMW F25 X3 35i, which makes it the straightforward choice. The second X3 was built 2010–2017, and the N55B30 was produced 2009–2017, so check that your car's build date falls inside that window. Confirm the drive type (rear-drive or xDrive), the gearbox (manual or automatic) and the emissions standard, because these can change the sump, the flywheel and the software. Send us the VIN and we check all of it for you.

How much is a replacement engine for a BMW F25 X3 35i?

We have 2 N55B30 engines from F25 donor cars, priced from 5.372,00 € to 5.522,00 €. Delivery to your door is included, and the engine carries a 12-month warranty when fitted by a qualified workshop. Add fitting labour and the parts you replace at the same time — seals, cooling parts and mounts — to estimate the total.

Fitting a replacement engine in the X3 35i

1. Inspect or replace the timing chain parts. Look at the guides and tensioner. On high-mileage engines, replacing them now costs far less than doing it later.
2. Prepare the turbo. Fit new oil feed and return seals, clean the intercooler and pipes of any oil or debris from the old engine, and prime the turbo with oil before starting.
3. Reset VANOS adaptations. Clear the VANOS adaptations so the ECU learns the camshaft positions of the new engine.
4. Teach the Valvetronic limit stops. Run the Valvetronic learning routine so the ECU knows the eccentric shaft limits.
5. Fill with the right oil and prime it. Fill with new oil of the correct specification and a new filter. Crank with the fuel and ignition disabled until oil pressure builds.
6. Coding and adaptations. On modern BMWs, the engine ECU must be matched to the car's immobiliser (CAS, FEM or BDC). Reset adaptations, register the battery and clear faults with diagnostic software.
7. First start and leak check. Start the engine, let it idle and watch oil pressure, temperature and fault codes. Check for leaks and bleed the cooling system.
8. First 1,000 km. Drive gently for the first few hundred kilometres, vary the engine speed and avoid full load. Change the oil and filter after about 1,000 km to remove any assembly debris.

The full fitting and first-start procedure.

Delivery, warranty and payment

Every X3 35i engine we sell is drained, sealed at each opening, strapped to a heat-treated pallet and shrink-wrapped before it leaves Hamburg. You receive photographs of the packed engine and a tracking number.

Delivery is door to door and included in the price. Most European addresses receive the engine within five to ten working days; Germany and its neighbours are usually faster.

Every engine carries a 12-month warranty on eligible internal failure when a qualified workshop fits it with new fluids and filters. Payment is by card, bank transfer or crypto; your invoice is emailed as soon as you order.

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