G22/G23 · 2020–…

BMW 420i Coupé/Convertible G22/G23 · 184 hp (since 2020)

The 420i is the entry-level petrol 4 Series Coupé and Convertible, with a 2.0-litre four-cylinder of 135 kW (184 hp). 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
2020–…
Documented market
Europe

Transmission

  • Automatic · 8 speeds · 2020

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

Specification source : [2] BMW Group [3] BMW Group [6] BMW Group [7] BMW Group [10] BMW Group [11] BMW Group

What distinguishes this version

1,998 cc four-cylinder petrol turbo (ADAC engine code 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; the Coupé was also offered with xDrive from 07/2021 to 01/2024 according to ADAC, and the 2024 line-up returns to rear-wheel drive only. BMW quotes 7.5 s for 0–100 km/h and 240 km/h for the Coupé, 7.8 s and 238 km/h for the 420i xDrive Coupé, 8.2 s and 236 km/h for the Convertible. Euro 6d at launch, Euro 6e on the 01/2024 sheets. The VI/20 handbook allows a 1,600 kg braked trailer for the Coupé. Timing chain according to ADAC.

Source : [3] [7] [6] [11] [14] [15] [12]

Engine oil: quantity

Oil change: 5.25 l according to BMW’s specification sheets (06/2020, 03/2021, 01/2024). Approvals and viscosity grades: see the “B48 engine” block on this page. The top-up list in the 4 Series handbook depends on the edition (VI/20 or X/23, see the generation page). The level is measured electronically: car level, engine warm and running, CAR › Vehicle status › Engine oil level › Oil level measurement › Start measurement. Only add oil when the car asks for it, in the quantity given in the message.

Source : [3] [6] [10] [11] [12]

What the service display tracks

The car calculates each due date from how it is used (Condition Based Service) and briefly shows the next date or remaining distance after switching on; details, including statutory inspections, are under CAR › Vehicle status › Service requirements, and completed work under Service History. BMW’s regular maintenance covers engine oil, brake fluid, a vehicle check, air filter, cabin microfilter and spark plugs. Brake fluid and, where applicable, oil and microfilter also depend on time. Neither the handbook nor BMW’s list sets a mileage or period.

Source : [12] [1]

Prepare the next service

Check the power on the registration document (135 kW). Note the items and dates shown under CAR › Vehicle status › Service requirements. Give the service advisor the key the car was last driven with: the car stores its service data in it. Ask for 5.25 l of a BMW-approved oil. Have the VIN checked against the starter recalls listed by ADAC, then check that the work is entered in the electronic Service History, which a later owner can also view.

Source : [12] [14] [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 : [21] [26] [29] [19] [18] [25]

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 : [23] [24] [20] [27] [28] [26] [19]

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 : [21] [29]

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 : [21] [29] [18] [19]

Maintenance and records

Engine oil (2020 handbook)

Due date calculated by CBS

Oil change at the date the car displays, without running past it; BMW recommends having it done by a workshop. Top-up oils in the VI/20 handbook: petrol BMW Longlife-04, -12 FE or -17 FE+; diesel Longlife-04 or -12 FE (-12 FE is not suitable for the 25d, 35d, 40d and 50d diesels). Viscosities SAE 0W-20, 5W-20, 0W-30, 5W-30, 0W-40 or 5W-40, with 0W-20 and 5W-20 excluded for diesel. If unavailable, up to 1 litre of ACEA C2 or C3. No additives.

Source [12]

Engine oil (2024 handbook)

Due date calculated by CBS

Oil change at the date the car displays. Top-up oils in the X/23 handbook: petrol BMW Longlife-12 FE, -17 FE+ or -19 FE (without a petrol particulate filter, BMW prefers Longlife-01 FE to -12 FE); diesel Longlife-12 FE or -17 FE+. Viscosities SAE 0W-20 or 0W-30 only. If unavailable, up to 1 litre of ACEA C2 or C5. No additives.

Source [13]

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]

Time-based items

Calendar-based (CBS)

Brake fluid and, where applicable, engine oil and the microfilter/activated-carbon filter also depend on time. The VI/20 handbook states that periods with the battery disconnected are not taken into account: have the workshop update these items. The handbook gives no period.

Source [12]

Coolant

Regular check, engine cold

Level correct at the Max mark in the expansion tank filler neck, engine cold and air conditioning off. BMW recommends coolant to BMW LC-18, mixed 50:50 with water; do not mix additives of different colours. At delivery or after a workshop visit the tank may be overfilled: the normal level settles with use.

Source [13]

Soft top (Convertible)

Every wash; impregnate every 3–5 washes

Do not open the roof when wet, snow-covered, iced or dirty, and do not leave it open for more than a day while damp. Clean it with a dedicated soft-top cleaner, never with stain remover, thinner, solvent or petrol. After three to five washes, treat it with an impregnating agent. It is not designed to carry a roof rack.

Source [30]

Questions about this version (5)

Is the 420i Convertible slower than the Coupé?

Slightly: BMW quotes 8.2 s for 0–100 km/h and 236 km/h for the Convertible, against 7.5 s and 240 km/h for the Coupé, with the same 135 kW and 300 Nm. Engine, gearbox and oil quantity (5.25 l) are identical.

Source : [3] [6]

Can I find a 420i with xDrive?

Only as a used Coupé: ADAC lists the 420i xDrive Coupé from July 2021 to January 2024 (B48B20A, 300 Nm), and BMW quotes 7.8 s for 0–100 km/h. The 2024 Coupé and Convertible sheets list the 420i with rear-wheel drive only, and none of the BMW documents we read mentions a 420i xDrive Convertible.

Source : [15] [7] [10] [11]

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).

Source : [12] [13]

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. Not every car is affected: have your VIN checked.

Source : [14]

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 : [12]

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 06/2020 — The new BMW 4 Series Coupé (press kit, long version)

    BMW Group · EN · Europe (German base data) · p. 2–3 (model variants at launch), p. 13 (Dingolfing, launch October 2020), pp. 23–28 (engines, 48V mild hybrid, eight-speed Steptronic, xDrive) · Accessed 08/10/2026

  3. [3] BMW Media information 06/2020 — Technical specifications, the new BMW 4 Series Coupé

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

  4. [4] BMW Group Plant Dingolfing, 1 July 2020 — Start of production for new BMW 4 Series Coupé

    BMW Group · EN · Europe (German base data) · p. 1 · Accessed 08/10/2026

  5. [5] BMW Media information 09/2020 — The all-new BMW 4 Series Convertible (press kit, long version)

    BMW Group · EN · Europe (German base data) · pp. 2–3 (model variants), p. 4 (launch March 2021, Dingolfing), pp. 10–11 (panel bow soft top, 18 s, 50 km/h, boot 300/385 l) · Accessed 08/10/2026

  6. [6] Specifications of the BMW 4 Series Convertible, valid from 03/2021

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

  7. [7] Specifications of the BMW 4 Series Coupé, valid from 07/2021

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

  8. [8] 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

  9. [9] BMW Media information 01/2024 — The new BMW 4 Series Coupé and the new BMW 4 Series Convertible (long version)

    BMW Group · EN · Europe (German base data) · pp. 2–4 (model variants), p. 13 (Dingolfing, launch March 2024), pp. 15–16 (powertrain, Steptronic Sport, 48V mild hybrid) · Accessed 08/10/2026

  10. [10] BMW Media information 01/2024 — Technical specifications, the new BMW 4 Series Coupé

    BMW Group · EN · Europe (German base data) · 420i to M440d xDrive Coupé: output, torque, engine oil (oil change), performance, emission rating · Accessed 08/10/2026

  11. [11] BMW Media information 01/2024 — Technical specifications, the new BMW 4 Series Convertible

    BMW Group · EN · Europe (German base data) · 420i to M440d xDrive Convertible: output, torque, engine oil (oil change), performance, emission rating · Accessed 08/10/2026

  12. [12] 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

  13. [13] 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

  14. [14] ADAC Autokatalog — BMW 420i Coupé Steptronic (10/20 - 01/24)

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

  15. [15] ADAC Autokatalog — BMW 420i Coupé xDrive Steptronic (07/21 - 01/24)

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

  16. [16] ADAC Autokatalog — BMW 420i 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

  17. [17] ADAC Autokatalog — BMW 420i Cabrio Steptronic (ab 07/25)

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

  18. [18] 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

  19. [19] 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

  20. [20] 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

  21. [21] 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

  22. [22] 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

  23. [23] 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

  24. [24] 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

  25. [25] 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

  26. [26] 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

  27. [27] 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

  28. [28] 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

  29. [29] 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

  30. [30] BMW 4er Cabrio (G23) Betriebsanleitung, Sach-Nr. 01405A9A8D8 – X/23 (online copy)

    BMW AG (online copy: Kfz-Handbuch.de) · DE · Germany · pp. 106–110 (Verdeck: Hinweise, Funktionsvoraussetzungen, manuelles Schließen), 389 (Verdeck reinigen und imprägnieren) · Accessed 08/10/2026

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