The Vauxhall 25TD is a 2,498 cc, inline‑four turbocharged diesel engine produced between 1988 and 1995. It features an indirect injection (IDI) design with a pre-chamber combustion system, a cast‑iron block and head, and a mechanically governed Bosch injection pump with exhaust gas recirculation (EGR). In standard tune it delivered 65 kW (88 PS) at 4,200 rpm and 190 Nm of torque at 2,400 rpm, providing robust, fuel-efficient performance suited to executive sedans and light commercial applications of the era.
Fitted to models such as the Vauxhall Carlton Mk2, Senator B, and Omega A, the 25TD was engineered for relaxed motorway cruising and dependable urban performance. Emissions compliance was achieved through EGR and improved combustion chamber design, allowing Euro 1 certification across all production years.
One documented concern is turbocharger oil seal failure leading to oil ingestion and pre-chamber coking, highlighted in Vauxhall Engineering Bulletin EB‑90‑04. This issue arises from prolonged high-load operation without adequate oil change intervals, causing turbo bearing wear and subsequent seal leakage. From 1991, Vauxhall introduced a revised turbo housing and oil feed restrictor to mitigate this failure mode.
Production years 1988–1995 meet Euro 1 standards (VCA UK Type Approval #VCA/VEH/6608).
The Vauxhall 25TD Diesel is a 2,498 cc inline‑four turbocharged indirect injection engine engineered for executive sedans and light commercial vehicles (1988–1995). It combines a mechanically controlled Bosch injection pump with a robust cast‑iron architecture and a single turbocharger to deliver strong low‑rpm torque and improved refinement over naturally aspirated predecessors. Designed to meet Euro 1 emissions standards, it balances durability with moderate performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,498 cc | |
| Fuel type | Diesel (EN 590) | |
| Configuration | Inline‑4, OHV, 8‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 95.0 mm × 88.0 mm | |
| Power output | 65 kW (88 PS) @ 4,200 rpm | |
| Torque | 190 Nm @ 2,400 rpm | |
| Fuel system | Bosch VE mechanical injection pump with indirect injection (pre-chamber) | |
| Emissions standard | Euro 1 | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Single KKK K14 turbocharger (non-VGT) | |
| Timing system | Gear‑driven camshaft (front‑mounted) | |
| Oil type | SAE 15W‑40 mineral diesel oil (API CD) | |
| Dry weight | 165 kg |
The turbocharged IDI design improves torque and drivability over naturally aspirated diesels but requires strict adherence to 10,000 km oil change intervals to prevent turbo bearing wear and oil seal failure. SAE 15W‑40 mineral diesel oil meeting API CD is essential for cam and bearing protection due to the absence of modern detergent packages. The Bosch VE pump demands clean, water-free diesel; fuel contamination accelerates plunger wear. Post-1991 engines include a revised turbo oil feed restrictor per Vauxhall EB‑90‑04—pre-1991 units should be retrofitted during turbo service. EGR operation increases pre-chamber carbon buildup, so periodic decoking is recommended for high-mileage engines.
Oil Specs: Requires SAE 15W-40 mineral diesel oil meeting API CD (Vauxhall Owner’s Handbook 1989). Modern low-SAPS oils are not recommended.
Emissions: Euro 1 certification applies to all 1988–1995 models (VCA Type Approval #VCA/VEH/6608). EGR system required for compliance.
Power Ratings: Measured under BS AU 14 standards. Output verified on dynamometer per Vauxhall PT‑1992.
Vauxhall Technical Information System (TIS): Docs V2498‑88, OM‑1990, EB‑90‑04
VCA Type Approval Database (VCA/VEH/6608)
British Standards Institution: BS AU 14 Engine Power Testing
The Vauxhall 25TD Diesel was used across Vauxhall's Carlton Mk2, Senator B, and Omega A platforms with longitudinal front-engine mounting and no external licensing. This engine received platform-specific adaptations—reinforced engine mounts in the Senator and modified intercooler ducting in the Omega—and from 1991 the introduction of a revised turbo oil feed system to address seal failures, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-hand side of the block near the injection pump mount (Vauxhall TIS V2498‑88). The full engine number begins with '25TD' followed by a sequential build code. Pre-1991 units use early-spec KKK K14 turbochargers (part #0281 450 001) without oil feed restrictors; post-1991 engines feature revised housings (part #0281 450 012) with integrated restrictors. Critical differentiation from 23 D: 25TD has turbocharger, EGR valve, and larger displacement. Cylinder head casting number '25TD' confirms identity.
The 25TD's primary reliability risk is turbocharger oil seal failure, with elevated incidence in high-mileage or poorly maintained engines. Vauxhall internal durability reports from 1992 noted turbo-related oil consumption in over 30% of pre-1991 units by 120,000 km, while UK DVSA historical data shows increased MOT failures due to smoke and EGR faults in preserved executive sedans. Extended oil change intervals and poor fuel quality accelerate wear in the Bosch VE pump and turbo bearings, making correct maintenance critical.
Analysis derived from Vauxhall technical bulletins (1988–1995) and UK DVSA historical failure statistics (1990–2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL 25-TD.
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
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