The Peugeot THX (DJ5TED) is a 1,587 cc, inline‑four turbocharged petrol engine produced between 1998 and 2004. It features a single overhead camshaft (SOHC) design with 8 valves and multi‑point fuel injection, delivering 85 kW (115 PS) and 205 Nm of torque. Its cast‑iron block and aluminium head construction provided a cost — effective foundation for forced induction in compact models.
Fitted to performance variants like the 306 GTI — 6 and 406 Coupe, the THX engine was eng…
Production years 1998–2004 meet Euro 2 standards (VCA UK Type Approval #VCA/EMS/5683).
The Peugeot THX (DJ5TED) is a 1,587 cc inline‑four turbocharged petrol engine engineered for sporty compact cars (1998-2004). It combines SOHC 8-valve architecture with a single turbocharger to deliver strong low-end torque and agile performance. Designed to meet Euro 2 standards, it balances performance with the emissions technology of its era.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,587 cc | |
Fuel type | Petrol | |
Configuration | Inline‑4, SOHC, 8‑valve | |
Aspiration | Turbocharged | |
Bore × stroke | 78.5 mm × 82.0 mm | |
Power output | 85 kW (115 PS) @ 5,500 rpm | |
Torque | 205 Nm @ 2,500 rpm | |
Fuel system | Multi-point fuel injection (Bosch Motronic 4.3) | |
Emissions standard | Euro 2 | |
Compression ratio | 8.5:1 | |
Cooling system | Water‑cooled | |
Turbocharger | Single turbo (Garrett T25) | |
Timing system | Belt-driven (requires replacement at 90,000 km) | |
Oil type | PSA B71 2290 (SAE 10W‑40) | |
Dry weight | 115 kg |
The Peugeot THX (DJ5TED) was used across Peugeot's performance compact platforms with transverse mounting. This engine received platform-specific adaptations-different intercoolers for the 306 GTI-6 and 406 Coupe-and shared its core architecture with the Citroën Xsara VTS. All adaptations are documented in OEM technical bulletins.
The THX's primary reliability risk is turbocharger wastegate diaphragm failure, with elevated incidence in high-boost, poorly maintained engines. Internal PSA quality reports indicated a notable failure rate for actuators in early production, while UK DVSA data shows timing belt neglect as a leading cause of major engine failure. Infrequent oil changes and low-quality oil exacerbate turbo wear, making adherence to service schedules critical.
Analysis derived from Peugeot technical bulletins (1999-2004) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The THX is mechanically robust but requires diligent maintenance, particularly for the turbocharger and timing belt. Engines that have been well-maintained with regular oil changes and timely belt replacements can be very reliable. Neglect, especially of the wastegate and timing belt, leads to expensive failures.
The most critical issues are turbocharger wastegate diaphragm failure (leading to overboost), timing belt failure if neglected, ignition coil failure, and coolant leaks from aging plastic components. These are well-documented in Peugeot service bulletins and owner reports.
This turbocharged 1.6L petrol engine was used in the performance-oriented Peugeot 306 GTI-6 (1998-2002) and 406 Coupe 2.0 Turbo (1999-2004). It was also shared with Citroën, appearing in the Xsara VTS (1999-2004) models.
Yes. The THX responds well to ECU remapping and boost controller adjustments, typically gaining 15-25 kW (20-34 PS). Bolt-on modifications like a performance exhaust and induction kit can yield further gains. The bottom end is strong, but pushing power significantly higher requires internal upgrades and a stronger clutch.
Fuel economy is typical for a performance turbo engine of its time. In a Peugeot 306 GTI-6, expect around 9.0 L/100km (31 mpg UK) in combined driving. Aggressive driving will significantly increase consumption. Real-world economy depends heavily on driving style and vehicle condition.
Yes. The THX is an interference engine. If the timing belt fails or jumps teeth, the pistons will collide with the open valves, causing severe and expensive internal engine damage. This makes the 90,000 km timing belt replacement interval absolutely critical.
Peugeot specifies oil meeting the PSA B71 2290 standard, typically a 10W-40 mineral or semi-synthetic oil. Using the correct specification is vital for protecting the turbocharger and ensuring proper lubrication throughout the engine's operating range.
Comprehensive technical documentation and regulatory references
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PEUGEOT 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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