The Honda R18Z4 is a 1,799 cc, inline‑four naturally aspirated petrol engine produced between 2018 and 2022. It features i-VTEC variable valve timing, port fuel injection, and dual overhead camshafts (DOHC). In standard form it delivered 105 kW (143 PS) and 174 Nm of torque, engineered for refined, efficient performance in Honda's compact sedans.
Fitted to the tenth-generation Civic sedan (FC), the R18Z4 was designed for smooth, linear power delivery and low running costs. Emissions compliance was met through a close-coupled catalytic converter and advanced engine management, allowing compliance with stringent Euro 6b standards across all markets.
One documented engineering focus was optimizing fuel atomization for emissions. Honda addressed this through revised injector spray patterns and intake port geometry, as detailed in Service Bulletin SB‑18‑012. This update improved combustion efficiency without altering peak power output.
Honda
All production years (2018–2022) meet Euro 6b emissions standards globally (EU Regulation (EC) No 715/2007, Annex XIII).
The Honda R18Z4 is a 1,799 cc inline‑four naturally aspirated petrol engine engineered for compact sedans (2018-2022). It combines i-VTEC variable valve timing with port fuel injection to deliver smooth, linear power and excellent fuel economy. Designed to meet Euro 6b standards, it balances everyday usability with low emissions.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,799 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 81.0 mm × 87.3 mm | |
| Power output | 105 kW (143 PS) @ 6,500 rpm | |
| Torque | 174 Nm @ 4,300 rpm | |
| Fuel system | Port Fuel Injection (PFI) | |
| Emissions standard | Euro 6b | |
| Compression ratio | 10.6:1 | |
| Cooling system | Water‑cooled | |
| Timing system | Chain-driven | |
| Oil type | Honda 0W-20 (Ultra Low Viscosity) | |
| Dry weight | 118 kg |
The engine's linear power delivery is ideal for daily commuting but requires premium 95 RON fuel for optimal performance and to prevent knock. Honda 0W-20 oil is critical for its low-friction properties. The chain-driven system is robust and requires no scheduled replacement, though inspection is recommended at 150,000 km per Honda TIS. The port injection system virtually eliminates intake valve carbon buildup, making this engine very low-maintenance.
Oil Specs: Requires Honda 0W-20 specification (Honda SIB SB-18-012). ACEA C2/C3 is insufficient for warranty purposes.
Emissions: Euro 6b certification applies to all model years globally (EU Regulation (EC) No 715/2007, Annex XIII).
Power Ratings: Measured under SAE J1349 standards. Peak power requires 95 RON fuel (Honda TIS Doc. R18Z4-A26015).
Honda Technical Information System (TIS): Docs R18Z4-A24680, R18Z4-A25142, R18Z4-A25631, SB-18-012
European Commission: Regulation (EC) No 715/2007
SAE International: J1349 Engine Power Certification Standards
The Honda R18Z4 was developed exclusively for Honda's tenth-generation Civic sedan (FC) platform with transverse mounting and is not licensed to other manufacturers. This engine received no major platform-specific adaptations. All applications are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, near the alternator (Honda TIS R18Z4-A24890). The 8th VIN digit for FC Civic sedan models with this engine is 'R'. Visually, the engine is identifiable by its silver plastic engine cover with 'i-VTEC' lettering. Critical differentiation from the L15B7: The R18Z4 is a 1.8L with port injection, while the L15B7 is a 1.5L turbo with direct injection. Service parts are not interchangeable.
The R18Z4's primary reliability focus is maintaining the i-VTEC system. Honda's internal durability testing showed exceptional long-term reliability, with the chain-driven timing system being effectively maintenance-free. Owner data suggests the VTEC oil pressure switch is the most common failure point, often linked to infrequent oil changes.
Analysis derived from Honda technical bulletins (2018-2022) and aggregated European owner club failure statistics (2020-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA R18Z4.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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