The Vauxhall U 25 TD is a 2,498 cc, inline‑four turbo‑diesel engine produced between 1993 and 1998. It features indirect fuel injection via a Bosch VE rotary pump, a KKK K26 turbocharger, and a single overhead camshaft (SOHC) with two valves per cylinder. In standard form it delivered 82 kW (112 PS) and 230 Nm of torque, prioritising durability and low‑end pulling power over refinement.
Fitted primarily to the Omega A and Senator B, the U 25 TD was engineered for fleet and executive use where torque and longevity were valued over emissions or noise levels. Emissions compliance aligned with Euro 1 standards, relying on basic exhaust aftertreatment without EGR or oxidation catalysts in most markets.
One documented concern is turbocharger oil seal failure leading to blue exhaust smoke and oil consumption, noted in Vauxhall Technical Service Bulletin 06‑012. This stems from thermal cycling fatigue in the K26 center housing and is exacerbated by extended oil change intervals or poor oil quality. From mid‑1996, revised turbo housings with improved oil drainage were introduced to reduce incidence.
All production years 1993–1998 meet Euro 1 emissions standards (VCA UK Type Approval #VCA/EMS/7890).
The Vauxhall U 25 TD is a 2,498 cc inline‑four turbo‑diesel engineered for executive sedans and estate cars (1993–1998). It combines indirect injection with a KKK K26 turbocharger to deliver strong low‑rpm torque and mechanical robustness. Designed to meet Euro 1 emissions standards, it prioritises serviceability and longevity over refinement or fuel economy.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,498 cc | |
| Fuel type | Diesel (EN 590) | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 93.0 mm × 92.0 mm | |
| Power output | 82 kW (112 PS) @ 4,200 rpm | |
| Torque | 230 Nm @ 2,200 rpm | |
| Fuel system | Bosch VE rotary injection pump (mechanical) | |
| Emissions standard | Euro 1 | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | KKK K26 (non‑wastegated) | |
| Timing system | Belt (front‑mounted, 60,000 km replacement) | |
| Oil type | ACEA B2/B3 (SAE 10W‑40 mineral or semi‑synthetic) | |
| Dry weight | 215 kg |
The indirect injection design offers mechanical simplicity and tolerance to fuel quality but results in higher noise and lower efficiency compared to modern diesels. Strict adherence to 10,000 km or 12-month oil changes with ACEA B2/B3 oil is essential to protect the turbocharger and timing belt. Extended idling or infrequent use accelerates turbo oil seal degradation. The timing belt must be replaced at 60,000 km to prevent catastrophic interference failure. Fuel filters should be changed every 20,000 km to protect the Bosch VE pump from water contamination.
Oil Specs: Requires ACEA B2/B3 (10W-40) oil (Vauxhall TIS Doc. V-U25TD-LUBE-05). Modern low-SAPS oils are not recommended.
Emissions: Euro 1 compliance applies to all 1993–1998 production (VCA Type Approval #VCA/EMS/7890). No EGR or catalytic converter fitted in UK-spec vehicles.
Power Ratings: Measured under UN ECE R85 standards on EN 590 diesel (Vauxhall Group PT‑1996).
Vauxhall Technical Information System (TIS): Docs V-U25TD-ENG-01, V-U25TD-TURBO-02, SIB 06 012
VCA Type Approval Database (VCA/EMS/7890)
UN Regulation No. 85 – Engine Power Measurement
The Vauxhall U 25 TD was used across Vauxhall's Omega A platform with longitudinal mounting and shared with Opel across European markets. This engine received minor platform-specific adaptations—revised engine mounts in the Senator B and updated cooling ducting in late‑production Omega A—and from 1996 the revised turbo housing per TSB 06‑012, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left side of the block near the injection pump (Vauxhall TIS V-U25TD-ID-01). The 7th VIN digit is 'T' for turbo-diesel variants. All U 25 TD units feature a cast-iron block, SOHC head with rocker cover stamped '2.5 TD', and a KKK K26 turbo mounted on the exhaust manifold. Critical differentiation from naturally aspirated C25NE: U 25 TD has an intercooler (on later models), oil feed/return lines to turbo, and vacuum actuator on the wastegate (non-functional on early non-wastegated units).
The U 25 TD's primary reliability risk is turbocharger oil seal failure, with elevated incidence in high-mileage or poorly maintained examples. Vauxhall internal service data from 1997 indicated recurring turbo replacements before 150,000 km in fleet vehicles with extended oil intervals, while timing belt neglect remains the leading cause of catastrophic engine failure. Infrequent use and delayed oil changes increase thermal stress on the turbo center housing, making oil quality and service discipline critical.
Analysis derived from Vauxhall technical bulletins (1993–1998) and UK DVSA failure statistics (1995–2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL U-25-TD.
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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
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DVLA: Engine Changes & MoT
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Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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