The Mazda L5-VEM is a 2,488 cc, inline-five turbocharged petrol engine produced since 2018. It features direct fuel injection, variable valve timing on both intake and exhaust, and a twin-scroll turbocharger, delivering high specific power output with improved thermal efficiency. The engine's design prioritizes low-inertia response and reduced pumping losses for enhanced drivability across the rev range.
Fitted exclusively to the Mazda6 (GJ) and CX-9 (KL) models in global markets, the L5-VEM was engineered for balanced performance and refined cruising. Emissions compliance was achieved through a gasoline particulate filter (GPF), cooled exhaust gas recirculation (EGR), and precise air-fuel control, enabling all units to meet Euro 6d-TEMP and US Tier 3 Bin 70 emissions standards regardless of market.
One documented concern is carbon buildup on intake valves due to port fuel injection absence, highlighted in Mazda Technical Service Bulletin No. TSB-2020-007. This issue stems from lack of detergent wash-down during normal operation, leading to potential misfires under light load. Mazda introduced revised piston ring groove geometry and updated ECU fuel trim logic in mid-2020 production to mitigate deposit accumulation and improve combustion stability.
Mazda
Production years 2018–2020 meet Euro 6d-TEMP; 2021–present models comply with Euro 6d and US Tier 3 Bin 70 standards (JAMA Type Approval #JAMA/ENG/2018-11).
The Mazda L5-VEM is a 2,488 cc inline-five turbocharged petrol engine engineered for mid-size sedans and SUVs (2018–present). It combines direct injection with twin-variable valve timing and a twin-scroll turbocharger to deliver rapid throttle response and high torque density. Designed to meet stringent global emissions regulations, it balances performance with improved fuel economy over previous generation engines.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,488 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-5, DOHC, 20-valve | |
| Aspiration | Turbocharged with twin-scroll turbocharger | |
| Bore × stroke | 83.5 mm × 90.0 mm | |
| Power output | 191 kW (260 PS) | |
| Torque | 420 Nm @ 2,000–4,000 rpm | |
| Fuel system | Gasoline direct injection (GDI) with 350 bar injector pressure | |
| Emissions standard | Euro 6d-TEMP / Euro 6d / US Tier 3 Bin 70 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled with electric water pump | |
| Turbocharger | Mitsubishi Heavy Industries TD04H-16T4R twin-scroll | |
| Timing system | Timing chain with hydraulic tensioner | |
| Oil type | Mazda Synthetic Oil 0W-20 | |
| Dry weight | 168 kg |
The direct injection system enables high compression and efficient combustion but requires strict adherence to 10,000 km oil changes using Mazda Synthetic Oil 0W-20 to prevent intake valve carbon buildup. High-octane premium fuel (RON 95 minimum) is critical to avoid knock under boost. Cold starts require no extended idling; engine warm-up occurs rapidly under light load. The GPF requires periodic regeneration cycles—avoid frequent short trips or prolonged idle to prevent clogging. Intake valve cleaning every 60,000 km is recommended per TSB-2020-007. ECU calibration is sensitive to ambient temperature and altitude; modifications must preserve factory stoichiometric control to maintain GPF efficiency and emissions compliance.
Oil Specs: Requires Mazda Synthetic Oil 0W-20 specification (Mazda SIB TSB-2020-007). ACEA C2/C3 oils are not acceptable due to ash content mismatch.
Emissions: Euro 6d certification applies to all global-market units (JAMA Type Approval #JAMA/ENG/2018-11). US models meet Tier 3 Bin 70.
Power Ratings: Measured under ISO 1585 standards. 191 kW output requires RON 95+ fuel quality (Mazda TIS Doc. L5-0012).
Mazda Technical Information System (TIS): Docs L5-0012, L5-0015, TSB-2020-007
JAMA Type Approval Database (JAMA/ENG/2018-11)
ISO 1585:1998 Road vehicles — Measurement of net engine power
The Mazda L5-VEM was used across Mazda's GJ/KL platforms with longitudinal mounting and exclusively licensed to Mazda for automotive applications. This engine received platform-specific adaptations—reinforced cylinder head gaskets in the CX-9 and revised intake runner profiles in the Mazda6—and from 2021 the facelifted GJ LCI models adopted revised piston ring land geometry and updated ECU calibrations, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the right cylinder head near the camshaft cover (Mazda TIS L5-0012). The 7th VIN digit indicates engine family ('L' for L5 series). Pre-2021 units feature silver aluminum intake manifold with visible throttle body; post-2021 units use black composite intake with integrated evaporative purge valve. Critical differentiation from L5-VE: L5-VEM has a twin-scroll turbocharger (distinctive rectangular housing) and a gasoline particulate filter (GPF) mounted directly behind the catalytic converter. Service parts require production date verification - piston rings for pre-2021 engines are incompatible with later units due to revised land geometry (Mazda TSB-2020-007).
The L5-VEM's primary reliability risk is intake valve carbon buildup leading to misfires and loss of power, with elevated incidence in urban stop-start driving. Internal Mazda reports from 2021 indicated up to 12% of early builds required intake cleaning before 80,000 km under frequent short-trip conditions. While JAMA records show minimal warranty claims for turbo failures, thermal stress from aggressive acceleration and poor warm-up cycles accelerate deposit formation. Extended idle times and low-speed driving increase oil vapor deposition on valves, making oil quality and interval adherence critical.
Analysis derived from Mazda technical bulletins (2019–2024) and JAMA warranty statistics (2020–2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MAZDA L5-VEM.
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