G26 · 2021–…

BMW 420i Gran Coupé G26 · 184 hp (since 2021)

The 420i is the entry-level Gran Coupé: a 2.0-litre four-cylinder petrol of 135 kW (184 hp) with rear-wheel drive. To check this is your version, compare with the 135 kW on the registration document. An oil change takes 5.25 l.

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Technical specifications

Fuel
Petrol
Power
184 PS / 135 kW
Displacement
1 998 cm³
Torque
300 Nm
Cylinders
4
Engine code
B48 (B48B20A)
Period covered
2021–…
Documented market
Europe

Transmission

  • Automatic · 8 speeds · 2021

Figures apply to the cited configuration and market; equipment and transmissions may vary by production date.

Specification source : [3] BMW Group [6] BMW Group

What distinguishes this version

1,998 cc four-cylinder (ADAC: B48B20A): 135 kW (184 hp) between 5,000 and 6,500 rpm, 300 Nm between 1,350 and 4,000 rpm. Eight-speed Steptronic, rear-wheel drive; Steptronic Sport as standard since the July 2024 update. 0–100 km/h in 7.9 s, 235 km/h (06/2021 and 07/2024 sheets). Euro 6d at launch, Euro 6e from 06/2023 according to ADAC. Timing chain according to ADAC.

Source : [3] [6] [5] [9]

Engine oil: quantity

Oil change: 5.25 l according to BMW’s specification sheets (06/2021, 07/2024). Approvals and viscosity grades: see the “B48 engine” block on this page.

Source : [3] [6]

What the service display tracks

Due dates are calculated by Condition Based Service from how the car is used. BMW’s regular maintenance covers engine oil, brake fluid, a vehicle check, air filter, cabin microfilter and spark plugs, each triggered by the calculated service requirement. BMW’s list sets no mileage or period: the reference is the date your car displays.

Source : [1]

Prepare the next service

Check the power on the registration document (135 kW) and note the items and dates the car displays. Ask for 5.25 l of a BMW-approved oil. Have the VIN checked against the recalls listed by ADAC and keep a record of every job.

Source : [9] [3]

BMW B48 petrol engine (2.0 l, four-cylinder)

This applies to every car fitted with the B48 engine.

What the B48 is

Inline four-cylinder petrol engine of 1,998 cc (82 mm bore, 94.6 mm stroke) with twin-scroll turbocharger, direct injection, Valvetronic and double VANOS, from the modular “Bx8” family shared with the B38 three-cylinder. Codes found: B48B20M0 and B48B20O0 (2017 2 Series Convertible, 220i and 230i), B48B20B according to ADAC (2018 F30 330i, 185 kW/252 PS), B48A20T1 (F40 M135i xDrive, 225 kW/306 hp and 450 Nm). In BMW’s naming the “A” in B48A stands for a transversely installed petrol engine. It also powers the F45 220i/225i Active Tourer.

Source : [14] [19] [22] [12] [11] [18]

Engine oil

BMW handbooks only list oils for topping up and leave the oil change to a qualified workshop; the list depends on the handbook edition. 2 Series Active Tourer F45 handbook (II/17): BMW Longlife-01, -01 FE, -04, -12 FE or -14 FE+, in SAE 0W-40, 0W-30, 5W-40 or 5W-30 (0W-20 and 5W-20 only for certain engines); otherwise up to 1 litre of ACEA A3/B4. F45 facelift handbook (VI/19): BMW Longlife-04, -12 FE or -17 FE+, in SAE 0W-20, 5W-20, 0W-30, 5W-30, 0W-40 or 5W-40; otherwise up to 1 litre of ACEA C2 or C3. 1 Series F40 handbook (II/22) / 2 Series Coupé G42 handbook (VI/22): BMW Longlife-12 FE or -17 FE+, in SAE 0W-20 or 0W-30 only; otherwise up to 1 litre of ACEA C2 or C5. Active Tourer U06 handbook (X/24): BMW Longlife-12 FE, -17 FE+ or -19 FE, in SAE 0W-20 or 0W-30; otherwise up to 1 litre of ACEA C2, C3 or C5. No additives. Quantity published by BMW: 5.25 l for the B48B20M0 and B48B20O0 (2017 2 Series Convertible) and for the B48A20T1 (F40 M135i xDrive, oil-change quantity). No quantity is sourced here for other installations.

Source : [16] [17] [13] [20] [21] [19] [12]

Timing drive

Chain, confirmed by ADAC. BMW’s Bx8 training document describes a two-part drive on the transmission side — a lower chain drives an intermediate shaft, which passes the drive to the upper camshaft chain — plus a separate chain for the oil/vacuum pump and spring-preloaded hydraulic tensioners; the inertia of the transmission reduces the loads on the chain. The sources consulted give no replacement interval.

Source : [14] [22]

What changed over the years

2014: BMW introduces the Bx8 family; its June 2014 training document describes the B46 variant of this four-cylinder (X1, 231 hp and 350 Nm, 11:1 compression). 2018: the B48B20B of the F30 330i gains a gasoline particulate filter and meets Euro 6d-TEMP (ADAC). 2019: the B48A20T1 of the M135i xDrive, presented by BMW as its most powerful four-cylinder, gets a reinforced crankshaft drive with a larger main bearing, new pistons with altered compression ratio, unbushed con rods, a larger turbocharger with integrated manifold (exhaust temperatures up to 1,025 °C) and higher-flow injectors.

Source : [14] [22] [11] [12]

Maintenance and records

Other maintenance items — petrol

As the service requirement dictates

BMW lists as regular maintenance: brake fluid, a vehicle check to BMW specifications, air filter, cabin microfilter and spark plugs. Each item is triggered by the service requirement the car calculates.

Source [1]

Questions about this version (5)

Did the 2024 update change the 420i?

Not mechanically: the 07/2024 sheet keeps 135 kW, 300 Nm, 7.9 s, 235 km/h and 5.25 l of oil. The update brings the Steptronic Sport transmission as standard and BMW Operating System 8.5; ADAC still lists the B48B20A from 07/2025.

Source : [3] [6] [5] [10]

Does the seat-belt recall concern my 420i?

Only cars built between 01/2022 and 03/2022: ADAC lists a May 2022 BMW recall for a faulty gas generator in the front seat-belt pretensioners, which raises the risk of injury in an accident and can cause a fire. The belts are checked and replaced if necessary.

Source : [9]

Which fuel?

The handbook specifies Super RON 95, with unleaded RON 91 as the minimum; ethanol is allowed up to 25% (E10, E25). Published output and consumption refer to RON 98 E10 (X/23 edition). Never use leaded petrol or metallic additives (manganese, iron). (These rules come from the Coupé handbook, which shares the same engines.)

Source : [7] [8]

Which recalls can apply to this version?

ADAC lists three BMW starter recalls covering this generation of the 4 Series: October 2025 (built 09/2015–09/2021), February 2026 (05/2020–10/2024) and July 2026 (07/2020–02/2026). A relay poorly protected against water, or wear deposits in it, can cause a short circuit and a fire; the starter is replaced. For cars built 01/2022–03/2022, ADAC adds a May 2022 recall: a faulty gas generator in the front seat-belt pretensioners; the belts are checked and replaced if necessary. Not every car is affected: have your VIN checked.

Source : [9]

How should a new car of this version be run in?

Up to 2,000 km, do not exceed 4,500 rpm or 160 km/h, avoid full load and kick-down and do not use Launch Control; then increase gradually. New tyres need a gentle approach for the first 300 km, the brakes for about 500 km. The same rules apply after these parts are replaced.

Source : [7]

Documentary sources

  1. [1] BMW Service Inclusive — Die Leistungen (bmw.de, archived 15/04/2026)

    BMW AG · DE · Germany · Section “Die Leistungen von BMW Service Inclusive” · Accessed 08/10/2026

  2. [2] BMW Media information 06/2021 — The all-new BMW 4 Series Gran Coupé (press kit, long version)

    BMW Group · EN · Europe (German base data) · p. 2 (model variants at launch), pp. 4–6 (Munich plant, market launch November 2021, dimensions, boot 470–1,290 l) · Accessed 08/10/2026

  3. [3] BMW Media information 06/2021 — Technical specifications, the all-new BMW 4 Series Gran Coupé

    BMW Group · EN · Europe (German base data) · 420i, 430i, M440i xDrive, 420d, 420d xDrive Gran Coupé: output, torque, engine oil (oil change), performance, emission rating · Accessed 08/10/2026

  4. [4] BMW model update measures for spring 2023 (press release)

    BMW Group · EN · Europe (German base data) · Section “BMW 4 Series and BMW M4 now with BMW Operating System 8 and BMW Curved Display” (March 2023) · Accessed 08/10/2026

  5. [5] BMW Media information 04/2024 — The new BMW i4 and the new BMW 4 Series Gran Coupé (long version)

    BMW Group · EN · Europe (German base data) · p. 2 (model variants), pp. 3–4 (Munich plant, market launch July 2024), pp. 18–19 (Steptronic Sport, engines, Euro 6e) · Accessed 08/10/2026

  6. [6] Technical data — BMW 4 Series Gran Coupé, valid as of July 2024

    BMW Group · EN · Europe (German base data) · 420i to 430d xDrive Gran Coupé: output, torque, engine oil (oil change), performance, emission rating · Accessed 08/10/2026

  7. [7] BMW 4er Coupé (G22) Betriebsanleitung, Sach-Nr. 01405A11254 – VI/20 (online copy)

    BMW AG (online copy: Kfz-Handbuch.de) · DE · Germany · pp. 175–176 (Servicebedarf, Service Historie), 330–331 (Einfahren, Partikelfilter), 380–382 (Kraftstoff, AdBlue), 386–390 (Motoröl, Kühlmittel), 392–393 (CBS), 415–418 (Gewichte, Anhängelasten) · Accessed 08/10/2026

  8. [8] BMW 4er Coupé (G22) Betriebsanleitung, Sach-Nr. 01405A9A824 – X/23 (online copy)

    BMW AG (online copy: Kfz-Handbuch.de) · DE · Germany · pp. 353–354 (Kraftstoffqualität), 360–361 (Motorölsorten), 362 (Kühlmittel), 365 (Condition Based Service, Standzeiten) · Accessed 08/10/2026

  9. [9] ADAC Autokatalog — BMW 420i Gran Coupé Steptronic (06/23 - 06/24)

    ADAC · DE · Germany · Technische Daten: Motorcode, Leistung, Drehmoment, Hubraum, Antriebsart, Nockenwellensteuerung, Modellstart/-ende, Schadstoffklasse; Rückrufe & Mängel · Accessed 08/10/2026

  10. [10] ADAC Autokatalog — BMW 420i Gran Coupé Steptronic (ab 07/25)

    ADAC · DE · Germany · Technische Daten: Motorcode, Leistung, Drehmoment, Hubraum, Antriebsart, Nockenwellensteuerung, Modellstart/-ende, Schadstoffklasse; Rückrufe & Mängel · Accessed 08/10/2026

  11. [11] BMW Media information 05/2019 — The all-new BMW 1 Series (press kit)

    BMW Group · EN · Europe (ACEA) · PDF p. 2 (launch dates), pp. 13–14 (xDrive, limited-slip differential), pp. 16–20 (engines, transmissions) · Accessed 08/10/2026

  12. [12] BMW UK Technical data — The all-new BMW 1 Series (118i, M135i xDrive)

    BMW (UK) Ltd. · EN · United Kingdom · Basic data summary (engine description B38A15M1 / B48A20T1); Motor: “Engine oil (exchange quantity)” · Accessed 08/10/2026

  13. [13] BMW 1er (F40) Betriebsanleitung, Sach-Nr. 01405A54108 – II/22 (online copy)

    BMW AG (online copy: Kfz-Handbuch.de) · DE · Germany · p. 182 (Servicebedarf), pp. 349–357 (Kraftstoff, AdBlue, Motoröl, Kühlmittel), pp. 360–361 (Condition Based Service, Service Historie) · Accessed 08/10/2026

  14. [14] BMW Technical training — B46 Engine (with the B38 three-cylinder)

    BMW of North America — Technical training (archive.org copy) · EN · USA · Information status June 2014 · §1 (B38/B46, “Bx8”) · §2.2.7 Chain drive, Bx8 engines (pp. 57–58) · Accessed 08/10/2026

  15. [15] BMW Technical training — B58 Engine

    BMW of North America — Technical training (archive.org copy) · EN · USA · Information status April 2015 · §1.2 Modular design · §1.3 Technical data (engine oil specification) · §2.2.4 Chain drive · Accessed 08/10/2026

  16. [16] BMW 2er Active Tourer (F45) Betriebsanleitung, Sach-Nr. 01402978274 – II/17 (online copy)

    BMW AG (online copy: Kfz-Handbuch.de) · DE · Germany · p. 96 (Servicebedarf), pp. 214–215 (Kraftstoffqualität), pp. 231–234 (Motoröl), pp. 235–236 (Kühlmittel), pp. 237–238 (Condition Based Service, Service Historie) · Accessed 08/10/2026

  17. [17] BMW 2er Active Tourer (F45) Betriebsanleitung, Sach-Nr. 01402666468 – VI/19 (online copy)

    BMW AG (online copy: Kfz-Handbuch.de) · DE · Germany · pp. 140–141 (Servicebedarf), pp. 270–273 (Kraftstoff, AdBlue), pp. 295–298 (Motoröl), pp. 299–300 (Kühlmittel), pp. 301–302 (Condition Based Service, Service Historie) · Accessed 08/10/2026

  18. [18] BMW parts catalogue (ETK) — BMW 2 Series F45 Active Tourer, Europe: model and engine list

    bmwfans.info (copy of the BMW ETK parts catalogue) · EN · Europe · Model, Engine: 214d/216d B37, 216i/218i B38, 218d/220d (and xDrive) B47, 220i/225i/225i xDrive B48, 225xe B38X · Accessed 08/10/2026

  19. [19] BMW UK Technical data — 2 Series Convertible LCI (F23LCI)

    BMW Group UK · EN · United Kingdom · Effective production week 44/2017 · engine type (B38B15M0, B48B20M0, B48B20O0, B58B30M0, B47D20U0, B47D20O0, B47D20T0), gearbox, “Engine oil (filling quantity)” · Accessed 08/10/2026

  20. [20] BMW 2er Coupé (G42) Betriebsanleitung, Sach-Nr. 01405A5E757 – VI/22 (online copy)

    BMW AG (online copy: Kfz-Handbuch.de) · DE · Germany · pp. 157–158 (Servicebedarf), 260–261 (Einfahren, Partikelfilter), 278 (Segeln), 311–315 (Kraftstoff, AdBlue), 316–321 (Motoröl, Kühlmittel), 322–323 (CBS, Service Historie), 326–328 (Batterie, Mild-Hybrid), 347–351 (Gewichte, Anhängelasten) · Accessed 08/10/2026

  21. [21] BMW 2er Active Tourer (U06) Betriebsanleitung, Sach-Nr. 01405B553E0 – X/24 (online copy)

    BMW AG (online copy: Kfz-Handbuch.de) · DE · Germany · pp. 170–171 (Service), 334 (Einfahren), 350–351 (Rekuperation, Segeln), 389–394 (Kraftstoff, AdBlue), 394–399 (Motoröl, Kühlmittel), 401 (CBS, Service Historie), 405–408 (Batterie, Mild-Hybrid), 412–413 (Starthilfe), 425–431 (Technische Daten) · Accessed 08/10/2026

  22. [22] ADAC — 330i Steptronic 07/2018–10/2018

    ADAC · DE · Europe / Allemagne · B48B20B, 185 kW/252 PS, filtre à particules essence ; suffixe divergent du catalogue MANN. · Accessed 08/10/2026

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