The Vauxhall Z12XEP is a 1,229 cc, inline‑four naturally aspirated petrol engine produced between 2005 and 2012. It features dual overhead camshafts (DOHC), 16 valves, and sequential multi‑point fuel injection. In standard form it delivered 59 kW (80 PS) at 5,600 rpm and 115 Nm of torque at 4,000 rpm, providing adequate urban performance with low fuel consumption.
Fitted to entry‑level models such as the Corsa C, Corsa D, and Agila B, the Z12XEP was engineered for cost‑effective city driving and light commuting. Emissions compliance was achieved through electronic throttle control and a three‑way catalytic converter, allowing Euro 4 certification across all production years.
One documented concern is premature wear of the camshaft followers, particularly in high‑mileage units subjected to infrequent oil changes. This issue, referenced in Vauxhall Technical Service Bulletin TSB‑05‑02‑11, is attributed to marginal lubrication under sustained high‑rpm operation. Later ECOTEC variants introduced revised cam profiles and hardened followers to mitigate this wear mode.
All production years (2005–2012) meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/2005/1123).
The Vauxhall Z12XEP is a 1,229 cc inline‑four naturally aspirated petrol engine engineered for compact city cars (2005–2012). It combines DOHC architecture with sequential multi‑point fuel injection to deliver responsive low‑end torque and fuel efficiency. Designed to meet Euro 4 emissions standards, it balances urban drivability with modest maintenance requirements.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,229 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 72.0 mm × 75.5 mm | |
| Power output | 59 kW (80 PS) @ 5,600 rpm | |
| Torque | 115 Nm @ 4,000 rpm | |
| Fuel system | Sequential multi‑point injection (Bosch Motronic ME7.9.7) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain (front‑mounted, maintenance‑free design) | |
| Oil type | GM‑LL‑A‑025 (SAE 5W‑30 or 10W‑40) | |
| Dry weight | 98 kg |
The Z12XEP offers light, responsive performance ideal for city driving but is sensitive to oil quality—infrequent changes accelerate cam follower wear, especially under sustained high-RPM use. Use of GM‑LL‑A‑025‑compliant oil (5W‑30 or 10W‑40) is essential to maintain valve train longevity. The Bosch Motronic system requires 95 RON minimum fuel; prolonged use of lower octane can cause knock and pre‑ignition damage. Early detection of tappet noise or loss of power is critical—per TSB‑05‑02‑11, worn cam followers often manifest after 100,000 km without proper oil maintenance. Regular oil replacement (every 10,000 km or 12 months) with OEM‑approved specification helps prevent premature mechanical wear.
Oil Specs: Requires GM‑LL‑A‑025 specification (Vauxhall Owner’s Manual, 2007). Equivalent to ACEA A3/B3 or A3/B4.
Emissions: Euro 4 certification applies to all 2005–2012 Z12XEP units (VCA Type Approval #VCA/EMS/2005/1123). No Euro 5 variants exist.
Power Ratings: Measured under ISO 1585 standards. Power output assumes 95 RON fuel and ambient conditions per EU Directive 93/116/EEC.
Vauxhall Technical Information System (TIS): Docs TIS‑Z12‑101 to TIS‑Z12‑104
Vauxhall Service Bulletin TSB‑05‑02‑11
VCA Type Approval Database (VCA/EMS/2005/1123)
ISO 1585: Road vehicles — Engine test code
The Vauxhall Z12XEP was used across Vauxhall's Corsa C, Corsa D, and Agila B platforms with transverse mounting and shared with Opel under GM’s global ECOTEC strategy. This engine received platform-specific adaptations—revised engine mounts in the Agila B and updated intake manifolds in the Corsa D—and from 2009 minor ECU calibrations were introduced to refine cold-start emissions, creating minor software interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front timing cover near the crankshaft pulley (Vauxhall TIS TIS‑Z12‑106). The 8th VIN digit indicates engine displacement ('1' for 1.2L). Z12XEP units feature a black plastic intake manifold with 'ECOTEC' branding and a Bosch Motronic ME7.9.7 ECU mounted near the firewall. Critical differentiation from Z10XEP: Z12XEP has 1,229 cc displacement (vs. 999 cc) and uses a different camshaft profile. Engine blocks are visually similar, but Z12XEP has a larger bore and distinct cam cover casting.
The Z12XEP's primary reliability risk is cam follower wear, with elevated incidence in vehicles subjected to infrequent oil changes or sustained high‑rpm driving. Vauxhall internal quality data from 2009 indicated measurable cam wear in engines exceeding 120,000 km without adherence to service intervals, while UK DVSA MOT records show negligible emissions failures but occasional advisory notices for tappet noise. Extended service intervals and short‑trip urban use increase valve train stress, making oil quality and change frequency critical.
Analysis derived from Vauxhall technical bulletins (2005–2012) and UK DVSA failure statistics (2010–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL Z-12-XEP.
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Regulation (EC) No 715/2007
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