F32/F33/F36 · 2016–2020

BMW 420i · B48B20A · 184 PS (2016–2020)

The 420i produces 135 kW (184 PS) with the 1998 cc B48B20A engine. This page covers 2016–2020. Identify this 420i by its B48B20A engine and 135 kW output. The range also includes 420i N20, 135 kW, so parts and service requirements cannot be selected from the 4 Series name alone. Covered bodies are listed on this page.

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Technical specifications

Fuel
Petrol
Power
184 PS / 135 kW
Displacement
1 998 cm³
Engine code
B48B20A
Period covered
2016–2020
Documented market
Europe

Transmission

  • Manual · 6 speeds
  • Automatic · 8 speeds

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

Specification source :

Identity and distinguishing features

The 420i produces 135 kW (184 PS) with the 1998 cc B48B20A engine. This page covers 2016–2020. Bodies covered: Coupé, Convertible, Gran Coupé. Dates combine documented configurations; not every body and transmission combination was available throughout. Identify this 420i by its B48B20A engine and 135 kW output. The range also includes 420i N20, 135 kW, so parts and service requirements cannot be selected from the 4 Series name alone. Covered bodies are listed on this page.

Source : [1] [7] [2] [3] [6] [4] [5]

Engine oil

BMW’s published oil-change quantity is 5.25 l. This is a service quantity, not an amount to pour in as a top-up: check the level after filling. Oil approvals, timing drive and shared engine characteristics are detailed in the engine section.

Source : [1] [7] [2] [3] [6] [4] [5]

Maintenance and CBS deadlines

CBS calculates deadlines from use; read distance and date under Vehicle information → Vehicle status → Service requirements. Oil, front and rear pads, brake fluid and vehicle check are separate items. This handbook does not set a universal oil mileage or a numeric brake-fluid interval here. The F32 handbook’s service table specifies oil, oil filter and air-conditioning microfilter at every oil service; spark plugs and air filter at every second oil service. Change the air filter sooner in dusty conditions. This table comes from the VI/13 handbook. For engines introduced later, confirm service counters and the VIN-specific plan before applying the same frequency.

Source : [8] [9] [10] [11]

Documented faults and recalls

ADAC notes springs or dampers requiring inspection and occasional oil leaks. Its diesel review also documents the EGR-cooler recall: an internal leak may cause a fire risk. Check affected engines, periods and completed work by VIN; this diesel recall does not automatically apply to petrol versions.

Source : [7]

Prepare the service

Bring the VIN, build month, B48B20A code and 135 kW rating. Record CBS dates and counters, previous oil services and filter changes; bring the key used for the last journey. Have the oil and work itemised on the invoice and the service recorded. Report storage with the battery disconnected so time-based deadlines can be corrected.

Source : [8] [9] [10] [11]

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 : [15] [20] [23] [13] [12] [19]

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 : [17] [18] [14] [21] [22] [20] [13]

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 : [15] [23]

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 : [15] [23] [12] [13]

Maintenance and records

Engine oil change

Oil deadline displayed by CBS

Record remaining date and distance before work. Use the version-specific quantity and a VIN-approved oil; check the level and record the oil service once completed. The consulted document does not justify a universal fixed mileage.

Source [9]

Brake fluid

Brake-fluid service date

Read the brake-fluid deadline separately from pad wear. Compare it with the last replacement invoice; report storage with the battery disconnected before correcting service dates. Reset only completed work.

Source [9]

Vehicle check

Vehicle-check deadline, separate from oil service

Keep the CBS vehicle-check item separate from oil service. Provide service history and the key last used so the workshop can read actual requirements. An oil change alone does not prove the vehicle check was completed.

Source [9]

Questions about this version (5)

Which engine powers this 184 PS 420i?

The 420i produces 135 kW (184 PS) with the 1998 cc B48B20A engine. This page covers 2016–2020. Bodies covered: Coupé, Convertible, Gran Coupé. Dates combine documented configurations; not every body and transmission combination was available throughout.

Source : [1] [7] [2] [3] [6] [4] [5]

How much oil does this B48B20A 420i take?

BMW’s published oil-change quantity is 5.25 l. This is a service quantity, not an amount to pour in as a top-up: check the level after filling. Oil approvals, timing drive and shared engine characteristics are detailed in the engine section.

Source : [1] [7] [2] [3] [6] [4] [5]

Which filters or plugs should I plan for this 420i?

CBS calculates deadlines from use; read distance and date under Vehicle information → Vehicle status → Service requirements. Oil, front and rear pads, brake fluid and vehicle check are separate items. This handbook does not set a universal oil mileage or a numeric brake-fluid interval here. The F32 handbook’s service table specifies oil, oil filter and air-conditioning microfilter at every oil service; spark plugs and air filter at every second oil service. Change the air filter sooner in dusty conditions. This table comes from the VI/13 handbook. For engines introduced later, confirm service counters and the VIN-specific plan before applying the same frequency.

Source : [8] [9] [10] [11]

What distinguishes this 184 PS 420i?

Identify this 420i by its B48B20A engine and 135 kW output. The range also includes 420i N20, 135 kW, so parts and service requirements cannot be selected from the 4 Series name alone. Covered bodies are listed on this page.

Source : [1] [7] [2] [3] [6] [4] [5]

Which recalls should be checked for this 420i?

ADAC notes springs or dampers requiring inspection and occasional oil leaks. Its diesel review also documents the EGR-cooler recall: an internal leak may cause a fire risk. Check affected engines, periods and completed work by VIN; this diesel recall does not automatically apply to petrol versions.

Source : [7]

Documentary sources

  1. [1] MANN-FILTER — Passenger car catalogue 2020/21

    MANN+HUMMEL · DE · Europe · Printed pp. 35–37: E90/E91 engine codes. Applicability dates may group E92/E93 and export markets. · Accessed 08/10/2026

  2. [2] BMW — 4 Series Coupé, 06/2013

    BMW Group · EN · Europe · Technical specifications pp. 27–32: 428i, 435i, 420d; oil quantities. · Accessed 08/10/2026

  3. [3] BMW — 4 Series Gran Coupé, 02/2014

    BMW Group · EN · Europe · Technical specifications: 420i, 428i, 435i, 418d, 420d; body-specific oil quantities. · Accessed 08/10/2026

  4. [4] BMW — spring 2015 range updates

    BMW Group · EN · Europe · 418d Coupé and 420d modular diesel changes, March 2015. · Accessed 08/10/2026

  5. [5] BMW — spring 2016 range updates

    BMW Group · EN · Europe · 420i, 430i, 440i and 425d: March 2016, before the body facelift. · Accessed 08/10/2026

  6. [6] BMW — 4 Series technical specifications, 01/2017

    BMW Group · EN · Europe · Coupé, Convertible, Gran Coupé: power, displacement, gearbox and oil change. · Accessed 08/10/2026

  7. [7] ADAC — BMW 4er 2013–2020 Diesel

    ADAC · DE · Europe · History, engine specification table, EGR recall and underbody observations. · Accessed 08/10/2026

  8. [8] BMW — 4er Coupé Betriebsanleitung VI/13

    BMW AG — owner’s handbook · DE · Europe · Printed p. 80: service display, oil or maintenance table. · Accessed 08/10/2026

  9. [9] BMW — 4er Coupé Betriebsanleitung VI/13

    BMW AG — owner’s handbook · DE · Europe · Printed p. 200: service display, oil or maintenance table. · Accessed 08/10/2026

  10. [10] BMW — 4er Coupé Betriebsanleitung VI/13

    BMW AG — owner’s handbook · DE · Europe · Printed p. 201: service display, oil or maintenance table. · Accessed 08/10/2026

  11. [11] BMW — 4er Coupé Betriebsanleitung VI/13

    BMW AG — owner’s handbook · DE · Europe · Printed p. 202: service display, oil or maintenance table. · Accessed 08/10/2026

  12. [12] 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

  13. [13] 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

  14. [14] 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

  15. [15] 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

  16. [16] 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

  17. [17] 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

  18. [18] 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

  19. [19] 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

  20. [20] 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

  21. [21] 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

  22. [22] 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

  23. [23] 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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