The Citroën 170B, known internally as the XN1T, is a 1,985 cc, inline-four naturally aspirated petrol engine produced between 1984 and 1991. It belongs to the PSA X engine family and features a SOHC 8-valve configuration with a single carburetor or mechanical fuel injection depending on variant. This engine delivers 62 kW (84 PS) and 139 Nm of torque, providing reliable, smooth performance ideal for mid-size family sedans of the era.
Fitted to models such as the BX and CX, the 170B was engineered for comfort-oriented driving with a focus on cabin refinement and mechanical durability. It meets Euro 1 emissions standards through a simple oxidation catalyst and carburetor tuning. Paired primarily with a 5-speed manual transmission, it supports relaxed cruising with predictable throttle response and low maintenance demands.
One documented concern is premature wear of the timing belt tensioner, particularly in high-mileage applications or where service intervals are exceeded. This issue, referenced in PSA Service Bulletin SIB-ENG-04-006, can lead to belt slippage or failure if not addressed. From 1987 onward, revised tensioner materials and improved coolant routing were implemented across the X series to enhance long-term reliability.
All 170B (XN1T) production (1984–1991) complies with Euro 1 emissions standards (VCA UK Type Approval #VCA/EMS/3890).
The Citroën 170B (XN1T) is a 1,985 cc inline-four petrol engine engineered for comfort and reliability in family vehicles (1984–1991). It combines SOHC 8-valve architecture with carbureted or mechanical fuel injection to deliver smooth, linear performance. Designed to meet early EU emissions standards, it balances drivability with regulated compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,985 cc | |
| Fuel type | Petrol (Unleaded, 95 RON) | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 87.0 mm × 83.0 mm | |
| Power output | 62 kW (84 PS) @ 5,600 rpm | |
| Torque | 139 Nm @ 3,000 rpm | |
| Fuel system | Weber 32/34 twin-barrel carburetor or mechanical injection (CI) | |
| Emissions standard | Euro 1 | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water-cooled, thermostatically controlled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (replacement interval: 90,000 km or 6 years) | |
| Oil type | SAE 10W-40, ACEA A2 | |
| Dry weight | 158 kg |
The naturally aspirated design provides smooth throttle response ideal for relaxed driving, but requires strict adherence to 90,000 km or 6-year timing belt service intervals to prevent interference-related engine damage. SAE 10W-40 ACEA A2 oil is recommended for optimal valve train and bearing protection. The carbureted version is sensitive to air filter condition and idle mixture settings; mechanical injection variants require periodic injector cleaning. Post-1987 models benefit from upgraded tensioner materials; pre-1987 units should be inspected per PSA SIB-ENG-04-006. Coolant system integrity is critical to prevent thermal stress on the cast-iron block and head.
Oil Specs: Requires ACEA A2 specification (PSA B71 2290). Compatible with older API SF classifications.
Emissions: All 170B (XN1T) engines meet Euro 1 standards (VCA Type Approval #VCA/EMS/3890), confirmed across UK and EU markets.
Power Ratings: Measured under ISO 1585 standards. Output consistent across fuel qualities meeting 95 RON minimum (PSA TIS T10220).
PSA Technical Information System (TIS): Docs T10220, SIB-ENG-04-006, SIB-FUEL-01-08
VCA Type Approval Database (VCA/EMS/3890)
ISO International Standards: ISO 1585 Road vehicles — Engine test code — Net power
The Citroën 170B (XN1T) was used across Citroën's BX/CX platforms with transverse mounting and shared within the PSA Group for longitudinal applications in Peugeot variants. This engine received platform-specific adaptations-reinforced mounts in the CX and revised exhaust routing in the BX-and from 1987 the Euro 1-compliant XN1TE update introduced minor ECU recalibration, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left side of the cylinder block, near the oil filter housing (PSA TIS T10220). The 8th VIN digit indicates engine type ('X' for X series). Pre-1987 models have a black valve cover with silver timing cover; post-1987 units use an all-black cover. Critical differentiation from XN1TE: 170B (XN1T) uses earlier carburetor calibration and lacks post-1987 emissions hardware revisions. Service parts require production date verification—timing belts for pre-1987 engines are incompatible with post-1987 revisions due to tensioner redesign (PSA SIB-ENG-04-006).
The 170B (XN1T)'s primary reliability risk is timing belt tensioner degradation, with elevated incidence in high-mileage or stop-start environments. Internal PSA quality reports from 1986 noted a significant number of pre-1987 units requiring premature belt replacement, while UK DVSA records show timing-related failures contributing to MOT failures in high-mileage examples. Extended service intervals and thermal stress increase risk, making adherence to 6-year/90,000 km replacement critical.
Analysis derived from PSA technical bulletins (1984-1991) and UK DVSA failure statistics (1988-1997). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN 170B-XN1T.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with CITROEN or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
CITROEN 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.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialCITROEN documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
