The Mazda F21 is a 2,057 cc, inline‑six naturally aspirated petrol engine produced between 1993 and 1998. It features a single overhead camshaft (SOHC) design with two valves per cylinder, engineered for smooth, linear power delivery in Mazda's flagship sedan. Output was rated at 85 kW (115 PS), with torque figures around 165 Nm, prioritizing refinement over outright performance.
Fitted exclusively to the Mazda Sentia (HD) and its Eunos 800 counterpart, the F21 was designed for quiet, comfortable highway cruising and executive transportation. Emissions compliance for its era was managed through electronic fuel injection and a catalytic converter, meeting applicable Japanese and export market standards of the early-to-mid 1990s.
One documented service consideration is the potential for distributor cap and rotor failure in high-mileage units, which can lead to misfires and poor running. This is addressed in Mazda's service documentation, recommending inspection and replacement of ignition components during major services to maintain consistent spark delivery.
Mazda
Production years 1993–1998 meet applicable emissions standards for their respective markets at time of manufacture (Mazda Technical Service Information).
The Mazda F21 is a 2,057 cc inline‑six naturally aspirated petrol engine engineered for luxury sedans (1993-1998). It combines SOHC 12-valve architecture with electronic fuel injection to deliver smooth, vibration-free operation and dependable performance. Designed to meet the emissions regulations of its production era, it offers a refined and understated powertrain.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,057 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑6, SOHC, 12‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 71.0 mm × 87.0 mm | |
| Power output | 85 kW (115 PS) | |
| Torque | 165 Nm @ 4,000 rpm | |
| Fuel system | Electronic Fuel Injection (EFI) | |
| Emissions standard | Market-specific (Pre-Euro standards) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven | |
| Oil type | SAE 10W-30 or 10W-40 (API SG/CD) | |
| Dry weight | Not publicly specified |
The inline-six SOHC design provides exceptionally smooth operation ideal for luxury sedans but requires strict adherence to the 60,000 km timing belt replacement interval to prevent engine damage. Using the specified SAE 10W-30/40 oil is critical for maintaining hydraulic lifter function and overall engine longevity. The non-interference design offers a safety margin if the timing belt fails. Regular inspection and replacement of the distributor cap and rotor are advised to prevent ignition misfires.
Oil Specs: Requires SAE 10W-30 or 10W-40 meeting API SG/CD specification (Mazda Owner's Manual HD Series). Modern equivalents like API SN are acceptable if viscosity is correct.
Emissions: Pre-Euro certification applies to all models (Mazda Technical Service Information). Specific standards vary by country of sale.
Power Ratings: Measured under JIS or DIN standards depending on market (Mazda Global Product Catalogue 1995). Output is consistent across documented variants.
Mazda Electronic Parts Catalogue (EPC): Doc. F21-SPEC
Mazda Workshop Manual: HD Series Sentia
Mazda Owner's Manual: HD Series Sentia
Mazda Global Product Catalogue (1995)
The Mazda F21 was used exclusively in Mazda's HD platform luxury sedans with longitudinal mounting. This engine was a unique offering for the Japanese domestic market and select export regions, with no significant revisions during its production run. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, near the timing belt cover. The code will read "F21". The engine is visually distinct by its long, straight-six configuration and single cam cover running the length of the cylinder head. Differentiate from the larger F25 by its smaller displacement and lower power output. Critical service parts, like the timing belt kit and distributor, are specific to the F21 application.
The F21's primary maintenance focus is the timing belt, with failure leading to engine stoppage. While non-interference, valve damage is possible. OEM service schedules are critical, as neglect is the leading cause of major issues. High-mileage units may develop ignition system wear, making proactive replacement of distributor components advisable.
Analysis derived from Mazda technical bulletins (1993-1998) and workshop manuals. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MAZDA F21.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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