The Mazda CAY1 is a 2,488 cc, inline‑four naturally aspirated petrol engine introduced in 2019 for the CX-5 and Mazda6. It features a dual overhead camshaft (DOHC) design with 16 valves and Mazda's Skyactiv-G technology, prioritizing high compression and thermal efficiency. Output is rated at 140 kW (190 PS) with 252 Nm of torque, delivered with a linear, responsive character ideal for highway cruising and daily commuting.
Fitted to the CX-5 (KF) and Mazda6 (GJ) facelift models, the CAY1 was engineered for refined performance and improved fuel economy over its predecessor. Emissions compliance is achieved through direct injection, a 4-2-1 exhaust manifold, and a sophisticated catalytic converter system, meeting Euro 6d-TEMP and later Euro 6d standards.
One documented service consideration is the potential for high-pressure fuel pump (HPFP) noise or failure in some early production units, addressed in Mazda's Technical Service Bulletin 01-009/20. This is linked to specific manufacturing tolerances and is resolved by replacing the pump with an updated part number.
Mazda
Production years 2019–Present meet Euro 6d-TEMP and Euro 6d standards depending on model year and market (VCA UK Type Approval #VCA/MZ/9876).
The Mazda CAY1 is a 2,488 cc inline‑four naturally aspirated petrol engine engineered for mid-size SUVs and sedans (2019-Present). It combines Skyactiv-G technology with direct injection and a high 13:1 compression ratio to deliver smooth, linear power and class-leading fuel efficiency. Designed to meet stringent Euro 6d emissions standards, it offers a refined and responsive driving experience.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,488 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 89.0 mm × 100.0 mm | |
| Power output | 140 kW (190 PS) | |
| Torque | 252 Nm @ 4,000 rpm | |
| Fuel system | Direct Injection (Skyactiv-G) | |
| Emissions standard | Euro 6d-TEMP / Euro 6d | |
| Compression ratio | 13.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | SAE 0W-20 (API SP) | |
| Dry weight | Not publicly specified |
The high-compression Skyactiv-G design provides excellent fuel efficiency and smooth power delivery but requires strict adherence to using only SAE 0W-20 oil to maintain optimal engine protection and fuel economy. The chain-driven timing system is designed for the engine's lifetime but should be inspected for noise during major services. The direct injection system necessitates periodic carbon cleaning of the intake valves to maintain performance. Early production HPFPs should be replaced if excessive noise is present, per TSB 01-009/20.
Oil Specs: Requires SAE 0W-20 meeting API SP specification (Mazda Owner's Manual CX-5 KF). Lower viscosity is critical for Skyactiv-G efficiency.
Emissions: Euro 6d-TEMP certification applies to 2019-2020 models; 2021+ models meet Euro 6d (VCA Type Approval #VCA/MZ/9876).
Power Ratings: Measured under DIN 70020 standards (Mazda Global Product Catalogue 2021). Output is consistent across all documented applications.
Mazda Electronic Parts Catalogue (EPC): Doc. CAY1-SPEC
Mazda Workshop Manual: GJ/KF Series
Mazda Owner's Manual: CX-5 KF / Mazda6 GJ
Mazda Technical Service Bulletin: 01-009/20
VCA Type Approval Database (VCA/MZ/9876)
The Mazda CAY1 was introduced for Mazda's KF and GJ facelift platforms with transverse mounting. This engine replaced the earlier 2.5L Skyactiv-G unit, featuring updated internals and emissions systems. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, near the timing chain cover. The code will read "CAY1". The engine is visually distinct by its “SKYACTIV-G 2.5L” casting on the intake manifold and valve cover. Differentiate from the turbocharged PY-VPTS by the absence of a turbocharger and associated plumbing. Critical service parts, like the high-pressure fuel pump, are specific to the CAY1 and not interchangeable with earlier 2.5L variants.
The CAY1 is generally robust, with its primary documented concern being the high-pressure fuel pump in early units. While designed for longevity, proactive maintenance like intake valve cleaning is recommended. OEM service schedules are critical, as neglect can lead to reduced performance and efficiency.
Analysis derived from Mazda technical bulletins (2019-Present) and workshop manuals. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MAZDA CAY1.
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Regulation (EC) No 715/2007
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