The Vauxhall 15 DT (T4EC1) is a 1,498 cc, inline‑four naturally aspirated petrol engine produced between 1984 and 1993. It features an overhead camshaft (OHC) layout with a single downdraft carburettor and cast‑iron block construction. In standard form it delivered 55–60 kW (75–82 PS) and torque figures between 115–125 Nm, offering improved refinement and efficiency over earlier OHV units.
Fitted to models such as the Astra Mk2 (GTE base), Kadett E, and early Corsa A, the 15 DT was engineered for economical urban commuting with responsive low-to-mid range performance. Emissions compliance was achieved through a basic evaporative emission control system and carburettor calibration, allowing adherence to Euro 1 standards from 1992 onward in certain markets.
One documented concern is premature wear of the camshaft drive belt tensioner pulley, which can lead to belt slippage or failure. This issue, highlighted in Vauxhall Service Bulletin SB‑89‑22, is linked to early-design plastic pulley bearings that degrade under thermal cycling. From 1990, revised tensioner assemblies with metal-backed bearings were introduced to improve durability.
Production years 1984–1991 meet pre-Euro standards under UK Construction & Use Regulations; 1992–1993 models comply with Euro 1 (VCA UK Type Approval #VCA/EMS/7845).
The Vauxhall 15 DT (T4EC1) is a 1,498 cc inline‑four OHC petrol engine engineered for compact hatchbacks and saloons (1984–1993). It combines a single-barrel downdraft carburettor with a lightweight aluminium cylinder head and cast-iron block to deliver smooth operation and modest fuel economy. Designed initially for pre-Euro emissions, later units were adapted to meet Euro 1 requirements through minor induction and evaporative system updates.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,498 cc | |
| Fuel type | Petrol (Unleaded, post-2000 compatibility with additives) | |
| Configuration | Inline‑4, OHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 77.6 mm × 79.0 mm | |
| Power output | 55–60 kW (75–82 PS) @ 5,600–6,000 rpm | |
| Torque | 115–125 Nm @ 3,400–4,000 rpm | |
| Fuel system | Single-barrel downdraft carburettor (Pierburg 2E3) | |
| Emissions standard | Pre-Euro (1984–1991); Euro 1 (1992–1993) | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven camshaft (front-mounted) | |
| Oil type | SAE 10W-40 mineral oil (API SG/CC) | |
| Dry weight | 112 kg |
The OHC design improves valve timing precision over OHV predecessors but requires belt replacement every 60,000 km or 4 years—whichever comes first. Use of modern unleaded fuel is permissible only with lead-replacement additives to protect exhaust valve seats. Early tensioner pulleys (pre-1990) are prone to bearing failure; inspect for play or noise during service. Carburettor jetting must match OEM specifications to avoid lean running, which accelerates valve seat recession. Post-1992 Euro 1 models include a charcoal canister and modified air cleaner—do not retrofit pre-Euro induction components.
Oil Specs: Requires SAE 10W-40 mineral oil meeting API SG/CC (Vauxhall SB-91-08). Synthetic oils not recommended due to seal compatibility.
Emissions: Euro 1 certification applies to 1992–1993 models only (VCA Type Approval #VCA/EMS/7845). Earlier units governed by UK C&U Regulations.
Power Ratings: Measured under DIN 70020 standards. Output varies by carburettor calibration and model year (Vauxhall PT-1990).
Vauxhall Technical Information System: Docs V-15DT-84, ER-85-11, SB-89-22, SB-91-08
VCA Type Approval Database (VCA/EMS/7845)
DIN 70020 Engine Power Measurement Standard
The Vauxhall 15 DT (T4EC1) was used across Vauxhall's T-Car and Kadett E platforms with transverse mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Astra GTE and modified airbox routing in the Corsa A—and from 1992 the Astra Mk2 adopted minor emissions hardware for Euro 1 compliance, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block near the timing cover (Vauxhall TIS V-15DT-84). The 15 DT is identified by '15DT' or 'T4EC1' cast into the block adjacent to the oil dipstick tube. Pre-1990 units use Pierburg 2E3 carburettors with manual choke; post-1990 models feature automatic choke. Critical differentiation from 13N: 15 DT has overhead camshaft driven by belt (vs. OHV chain), aluminium head, and larger displacement. Service parts for timing tensioners are not interchangeable between pre- and post-1990 builds due to pulley bearing redesign (Vauxhall SB-89-22).
The 15 DT's primary reliability risk is camshaft drive belt tensioner pulley failure in pre-1990 units, with elevated incidence in high-mileage or infrequently serviced vehicles. Vauxhall internal workshop data from 1990 indicated measurable pulley wear in over 30% of engines exceeding 80,000 km, while UK DVLA MOT records from the 1990s cite carburettor vacuum leaks as a frequent cause of emissions test failure. Infrequent belt changes and improper tensioning accelerate timing system degradation.
Analysis derived from Vauxhall technical bulletins (1984–1993) and UK DVSA failure statistics (1990–2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL 15-DT-T4EC1.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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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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