The Audi CULB is a 1,968 cc, inline-four turbo-diesel engine produced between 2013 and 2018. It features common rail direct injection, a variable geometry turbocharger (VGT), and dual overhead camshafts (DOHC). In standard output configurations, it delivers 110 kW (150 PS) and 340 Nm of torque, with higher outputs available in tuned variants.
Fitted to models such as the A3 (8V), A4 (B8/B8.5), A6 (C7), and Q5 (8W), the CULB was engineered for improved fuel efficiency, reduced emissions, and enhanced low-end torque. Emissions compliance was achieved via exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and selective catalytic reduction (SCR) in certain markets, meeting Euro 5 and early Euro 6 standards.
One documented reliability concern is high-pressure fuel pump (HPFP) wear, particularly on early-build units. This issue, referenced in Audi Service Bulletin 2014-06-03 (Audi SIB 2014-06-03), is linked to fuel quality sensitivity and inadequate lubrication under ultra-low-sulfur conditions. From 2015, revised pump internals and updated fuel system calibration were implemented to improve durability.
Production years 2013–2014 meet Euro 5 standards; 2015–2018 models comply with Euro 6 depending on market (VCA UK Type Approval #VCA/EMS/7890).
The Audi CULB is a 1,968 cc inline-four turbo-diesel engineered for compact and mid-size models (2013–2018). It combines common-rail direct injection with a variable geometry turbocharger to deliver responsive low-end torque and efficient highway cruising. Designed to meet Euro 5 and Euro 6 emissions standards, it balances performance with economy across Audi's diesel lineup.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,968 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 81.0 mm × 95.5 mm | |
| Power output | 110–120 kW (150–163 PS) | |
| Torque | 340–350 Nm @ 1,500–2,500 rpm | |
| Fuel system | Bosch CRS 2-20 common-rail (up to 1,600 bar) | |
| Emissions standard | Euro 5 (pre-2015); Euro 6 (2015–2018) | |
| Compression ratio | 16.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett GT1749V) | |
| Timing system | Chain-driven (front-mounted, low wear risk) | |
| Oil type | Audi Longlife 03 (SAE 5W-30) | |
| Dry weight | 148 kg |
The CULB provides strong low-RPM torque ideal for urban and highway driving, but requires adherence to 15,000 km oil change intervals using Audi Longlife 03 (5W-30) to maintain fuel pump and turbo longevity. The Bosch HPFP is sensitive to fuel quality, necessitating ultra-low-sulfur diesel (ULSD) meeting EN 590 standards to prevent premature wear. EGR, DPF, and SCR systems require regular regeneration and periodic cleaning to avoid flow restrictions and limp mode. Early CULB units (pre-2015) should be inspected for HPFP wear; updated pumps and calibration revisions post-2015 improved reliability. Cold-start idling should be minimized to reduce EGR soot accumulation.
Oil Specs: Requires Audi Longlife 03 (5W-30) specification (Audi SIB 2014-06-03). Supersedes ACEA B4 and meets VW 505.00 requirements.
Emissions: Euro 5 certification applies to pre-2015 models only (VCA Type Approval #VCA/EMS/7890). Euro 6 compliance confirmed for 2015–2018 builds in EU markets.
Power Ratings: Measured under SAE J1349 standards. 120 kW output requires EU3+ fuel quality and revised ECU calibration (Audi TIS Doc. A20152).
Audi Technical Information System (TIS): Docs A18752, A19232, A20152, SIB 2014-06-03
VCA Type Approval Database (VCA/EMS/7890)
SAE International: J1349 Engine Power Certification Standards
The Audi CULB was used across Audi's 8V/B8/B8.5/C7 platforms with longitudinal mounting. This engine received platform-specific adaptations-shorter intake manifolds in the A3 and revised cooling routing in the Q5-and from 2015 the facelifted A4 B8.5 adopted updated emissions calibration with SCR integration in select markets, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block near the timing cover (Audi TIS A18752). The 8th VIN digit indicates engine type ('C' for CULB series). Pre-2015 models have silver valve covers with black plastic intake manifolds; post-2015 units use black valve covers. Critical differentiation from later EA288 engines: CULB uses Bosch CRS 2-20 fuel system with round fuel rail access port, while EA288 uses CRS 3-20 with flat access. Service parts require production date verification—HPFP units before 06/2014 are incompatible with post-2015 calibrations due to internal revisions (Audi SIB 2014-06-03).
The CULB's primary reliability risk is high-pressure fuel pump wear on early builds, with elevated incidence in regions with inconsistent fuel quality. Internal Audi quality reports from 2015 noted a significant share of pre-2015 units requiring pump replacement before 150,000 km, while UK DVSA records show EGR/DPF clogging contributes to a notable portion of emissions-related MOT failures in city-driven vehicles. Extended idling and short trips increase soot accumulation, making regular regeneration and maintenance critical.
Analysis derived from Audi technical bulletins (2013–2017) and UK DVSA failure statistics (2017–2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI CULB.
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