Second Hand BMW i3 Engine

The BMW i3 was produced from 2013 onwards, with a significant update arriving in 2017 that brought a larger battery and revised electric drive unit on the BEV version, so crossing that boundary is not straightforward. The engine code stamped on your V5 or confirmed via a VIN check is the single most important detail — if the codes match between donor and recipient car, fitment is far more likely to be compatible. Whether a drive unit from a pre-2017 car will physically and electrically suit a post-2017 car is something you must confirm with the breaker against your specific registration, as internal changes may affect compatibility.

No — the i3 Range Extender (sometimes called the REx) carries a small two-cylinder petrol engine alongside the electric drive unit, which the standard battery-electric i3 does not have; the two variants use different powertrain layouts and are not interchangeable. The electric drive motor itself may share a code with the BEV version, but the REx has additional ancillaries, mounting points, and fuel system components that are absent on the pure-electric car. Always cross-reference the engine code and fuel type with the breaker against your registration before purchasing.

For the BMW i3, trim level does not affect the drive unit or engine specification — the powertrain fitted depends on the battery size and whether the car is BEV or REx, not on whether the donor was a lower or higher specification. Real i3 trim names in the UK such as standard, Sport, Lodge, and Loft describe interior and cosmetic packages only, so you may find the donor car has different interior trim, but that has no bearing on engine fitment. Confirm the engine code and variant (BEV or REx) match your car, and the trim level of the donor is irrelevant.

The 2017 model year brought a larger 94Ah battery pack and an updated electric drive unit to the i3 range, placing a potential engineering boundary between your 2015 car and a 2018 donor. Both generations use rear-mounted electric drive units, but internal changes across that 2017 boundary mean the units are not guaranteed to be like-for-like. You should confirm the engine code on your V5 and ask the breaker to match it exactly, checking specifically whether a post-2017 unit is compatible with a pre-2017 car against your registration.

This is a very important question for electric vehicles — the drive unit, battery management system, and ECU on the i3 can be paired to the specific vehicle, which may mean a used unit needs coding or re-pairing before the car will function correctly. We cannot state as fact exactly which components require coding on any given car, as this can vary by build date and specification. You must confirm with the breaker and your chosen installer what coding work will be needed against your specific registration before committing to a purchase.

The most useful thing you can supply is the engine or drive unit code, which will be on your V5 logbook or can be found via a VIN check — this matters far more than the year or trim level alone. You should also confirm whether your car is the battery-electric version or the Range Extender, and if possible note the battery pack size (60Ah pre-2017 or 94Ah from 2017 onwards). Having your full registration to hand allows the breaker to cross-reference ancillary parts and mounting details that may have changed during production.