The Vauxhall 25 E is a 2,490 cc, inline‑six naturally aspirated petrol engine produced between 1986 and 1993. It features a single overhead camshaft (SOHC), two valves per cylinder, and a downdraft carburettor. In standard form it delivered 95–103 kW (129–140 PS) and torque figures between 190–205 Nm, offering smooth power delivery and refined cruising for executive applications.
Fitted to models such as the Senator B and early Omega A, the 25 E was engineered for quiet, torque‑rich motoring with emphasis on drivetrain smoothness and highway stability. Emissions compliance was achieved through exhaust gas recirculation, crankcase ventilation, and lean carburettor calibration, meeting Euro 1 standards applicable in the UK and EU during its production era.
One documented concern is premature camshaft and tappet wear under high‑rpm or neglected‑maintenance conditions. This issue, referenced in Vauxhall Service Bulletin M‑25‑88, stems from marginal oil flow to the upper valvetrain during sustained operation. Later 25 E variants introduced revised cam profiles and improved rocker arm geometry to mitigate wear.
Production years 1986–1992 meet Euro 1 standards; 1993 models may have transitional Euro 2 compliance depending on market (VCA UK Type Approval #VCA/CU/9234).
The Vauxhall 25 E is a 2,490 cc inline‑six petrol engine engineered for executive sedans (1986–1993). It combines a single overhead camshaft with a downdraft carburettor to deliver smooth power and refined cruising. Designed to meet Euro 1 emissions standards, it balances performance with mechanical simplicity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,490 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑6, SOHC, 12‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.0 mm × 78.5 mm | |
| Power output | 95–103 kW (129–140 PS) @ 5,000–5,400 rpm | |
| Torque | 190–205 Nm @ 3,000–3,400 rpm | |
| Fuel system | Single-barrel downdraft carburettor (Zenith/Stromberg) | |
| Emissions standard | Euro 1 (1986–1992); transitional Euro 2 in 1993 | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven SOHC | |
| Oil type | SAE 20W‑50 mineral oil (API SF/CC) | |
| Dry weight | 165 kg |
The SOHC inline‑six layout provides inherent smoothness but requires diligent valve clearance checks every 10,000 km to maintain performance and prevent tappet wear. SAE 20W‑50 mineral oil is essential due to the engine’s wide bearing clearances and lack of modern filtration. Extended idling or frequent short trips accelerate sludge buildup in the rocker cover, potentially blocking oil galleries. Carburettor jets should be cleaned regularly to avoid lean running, which increases exhaust valve recession risk. Post‑1988 engines feature revised camshafts per Vauxhall SIB M‑25‑88.
Oil Specs: Requires SAE 20W‑50 mineral oil meeting API SF/CC (Vauxhall Owner’s Handbook 1987). Modern synthetics may cause oil pressure drop.
Emissions: Euro 1 certification applies to 1986–1992 models only (VCA Type Approval #VCA/CU/9234). Some 1993 models meet transitional Euro 2 depending on market.
Power Ratings: Measured under DIN 70020 standards. Power varies by carburettor type and model year (Vauxhall PT‑1991).
Vauxhall Technical Information System (TIS): Docs V9345, V9467
VCA Type Approval Database (VCA/CU/9234)
DIN 70020 Engine Power Certification Standards
The Vauxhall 25 E was used across Vauxhall's B‑Car and early Omega platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—reinforced mounts in the Senator B and revised cooling ducts in the Omega A—and from 1989 the facelifted Senator adopted updated carburettor jets and cam profiles, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-side engine block near the distributor mount (Vauxhall TIS V9345). The 25 E is identified by the “25E” cast into the block above the oil filter. Pre‑1989 units use Zenith carburettors with brass float bowls; post‑1989 models use Stromberg with plastic floats. Critical differentiation from 26NE: 25 E uses carburettor while 26NE uses fuel injection. Service parts require production date verification—camshafts before 07/1988 are incompatible with later rocker arms due to lobe profile changes (Vauxhall SIB M‑25‑88).
The 25 E's primary reliability risk is camshaft and tappet wear, with elevated incidence in high‑rpm or neglected‑maintenance use. Vauxhall internal reports from 1990 noted cam failures in over 11% of engines exceeding 100,000 km without proper oil changes, while UK DVSA historical data links poor valve adjustment to premature top‑end noise. Frequent short trips and use of incorrect oil viscosity increase wear, making regular clearance checks and oil quality critical.
Analysis derived from Vauxhall technical bulletins (1986–1993) and UK DVSA historical failure statistics (1990–1998). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL 25-E.
Comprehensive technical documentation and regulatory references
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VAUXHALL Official Site
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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
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VCA Certification Portal
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