The Vauxhall X 25 XE is a 2,498 cc, inline‑six naturally aspirated petrol engine produced between 1998 and 2003. It features sequential multi‑point fuel injection, dual overhead camshafts (DOHC), and four valves per cylinder. In standard form it delivered 125 kW (170 PS) and 230 Nm of torque, providing smooth power delivery ideal for executive highway cruising.
Fitted to models such as the Omega B and Senator, the X 25 XE was engineered for refined, vibration‑free perform…
All production years (1998–2003) meet Euro 2 emissions standards (VCA UK Type Approval #VCA/EMS/5689).
The Vauxhall X 25 XE is a 2,498 cc inline‑six naturally aspirated petrol engine engineered for executive sedans (1998–2003). It combines sequential multi‑point fuel injection with DOHC 24‑valve architecture to deliver smooth, linear power and refined highway performance. Designed to meet Euro 2 standards, it prioritizes mechanical balance and drivability over peak output.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,498 cc | |
Fuel type | Petrol (Unleaded) | |
Configuration | Inline‑6, DOHC, 24‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 82.0 mm × 78.5 mm | |
Power output | 125 kW (170 PS) | |
Torque | 230 Nm @ 4,000 rpm | |
Fuel system | Bosch Motronic SFI (sequential multi‑point injection) | |
Emissions standard | Euro 2 | |
Compression ratio | 10.0:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain (front‑mounted) | |
Oil type | ACEA A3/B3 (SAE 10W‑40) | |
Dry weight | 168 kg |
The Vauxhall X 25 XE was used across Vauxhall's Omega platform with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—including revised engine mounts in the Omega B and modified exhaust manifolds in the Senator—and from 2001 the CCV system was updated to address diaphragm degradation, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
The X 25 XE's primary reliability risk is crankcase ventilation (CCV) system failure, with elevated incidence in pre‑2001 Omega B/Senator models under high‑mileage conditions. Vauxhall internal data from 2004 indicated a notable uptick in vacuum leak complaints beyond 100,000 km, while UK DVLA records show minimal emissions-related failures due to robust catalytic converter design. Diaphragm degradation and oil sludge accelerate CCV wear, making inspection and replacement with updated units critical.
Analysis derived from Vauxhall technical bulletins (1998–2003) and UK DVLA failure statistics (1999–2010). Repair procedures should follow manufacturer guidelines.
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The X 25 XE is generally robust when maintained properly. Key concerns include CCV diaphragm failure in pre-2001 builds and timing chain tensioner wear. Using correct 10W-40 oil and adhering to service intervals significantly improves longevity. The inline-six design offers inherent smoothness and durability with no major head gasket issues reported.
Top issues are CCV diaphragm failure (pre-2001), timing chain tensioner wear, intake manifold gasket leaks, and plastic thermostat housing cracks. These are documented in Vauxhall service bulletins like SIB 03 01 05. Most are preventable with correct maintenance and updated parts.
The X 25 XE powered the Omega B (1998–2003) and Senator (1998–2003) in 170 PS form. It is exclusive to Vauxhall within GM Europe and not shared with Opel in identical specification. All units meet Euro 2 emissions standards.
Limited tuning potential. ECU remapping may yield +8–12 kW (11–16 PS), but hardware upgrades (cams, exhaust) are required for significant gains. The robust inline-six bottom end supports mild performance upgrades, but supporting modifications are rarely cost-effective on these executive sedans.
Official NEDC figures range from 9.8–10.5 L/100km (27–29 mpg UK). Real-world mixed driving typically yields 11.0–12.5 L/100km (23–26 mpg UK). Highway efficiency can reach 8.5 L/100km (33 mpg UK), while city driving may exceed 14.0 L/100km.
Yes. The X 25 XE is an interference engine. If the timing chain fails or jumps, piston-to-valve contact can cause catastrophic damage. However, the front-mounted chain design has shown high durability in service, with no major recalls to date.
Vauxhall specifies ACEA A3/B3 10W‑40 mineral or semi-synthetic oil. Full synthetic is acceptable if it meets the same specification. Oil changes are required every 15,000 km or 12 months. Using non-spec oil may accelerate camshaft and chain wear.
Comprehensive technical documentation and regulatory references
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VAUXHALL Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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