The Daewoo B12S3 is a 1,151 cc, inline-three petrol engine produced between 2000 and 2008. It was developed as a compact, fuel-efficient powerplant for entry-level hatchbacks and city cars. Featuring multi-point fuel injection (MPFI), a belt-driven overhead camshaft (SOHC), and 12 valves, it delivers 47 kW (64 PS) at 5,600 rpm and 100 Nm of torque at 3,000 rpm, supporting light-duty urban commuting.
Fitted primarily to the Daewoo Matiz (M150) and Chevrolet Spark (first generation), the B12S3 was engineered for affordability, ease of maintenance, and low running costs. Its emissions compliance meets Euro 3 standards through a three-way catalytic converter and oxygen feedback control, making it suitable for urban environments with moderate pollution regulations during its production run.
One documented service concern involves premature camshaft belt failure under extended service intervals, highlighted in Daewoo Service Bulletin DB-ENG-004 (2005). Inadequate tensioner maintenance or use of non-OEM belts can lead to belt slippage or fracture. From 2004 onward, revised tensioner materials and specified 60,000 km replacement intervals were introduced to improve reliability in warm climates and stop-start driving conditions.
Daewoo
Production years 2000–2005 meet Euro 3 standards; 2006–2008 models comply with Euro 4 depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Daewoo B12S3 is a 1,151 cc inline-three petrol engine engineered for city and urban hatchbacks (2000–2008). It combines multi-point fuel injection with a single overhead camshaft to deliver economical performance and compact packaging. Designed to meet Euro 3 and later Euro 4 standards, it balances low-cost ownership with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,151 cc | |
| Fuel type | Petrol (Unleaded, 95 RON) | |
| Configuration | Inline-3, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.0 mm × 86.8 mm | |
| Power output | 47 kW (64 PS) @ 5,600 rpm | |
| Torque | 100 Nm @ 3,000 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) | |
| Emissions standard | Euro 3 (pre-2006); Euro 4 (2006–2008, market-dependent) | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Toothed belt (interference type) | |
| Oil type | SAE 10W-30 or 10W-40 (API SL/CF) | |
| Dry weight | 98 kg |
The naturally aspirated design provides predictable, low-stress performance ideal for city driving but requires strict adherence to 60,000 km timing belt service intervals to prevent catastrophic engine damage. Use of OEM-spec or equivalent belts and tensioners is critical due to interference design. Fuel quality (minimum 95 RON) ensures knock resistance and longevity of the catalytic converter. Engine mounts degrade over time, especially in high-vibration environments; inspection every 40,000 km is advised. Post-2004 models benefit from revised tensioner materials; pre-2004 units should follow DB-ENG-004 upgrade path. Emissions system longevity depends on regular O2 sensor checks and avoiding short-trip driving.
Oil Specs: Requires SAE 10W-30 or 10W-40 meeting API SL/CF (Daewoo Owner's Manual Rev. 3.1). ACEA A1/B1 acceptable.
Emissions: Euro 3 certification applies to pre-2006 models (VCA Type Approval #VCA/EMS/5678). Euro 4 compliance from 2006 varies by market.
Power Ratings: Measured under ISO 1585 standards. Output consistent across fuel grades meeting 95 RON minimum (Daewoo TIS B12-8801).
Daewoo Technical Information System (TIS): Docs B12-8801, DB-ENG-004, DB-FI-002
VCA Type Approval Database (VCA/EMS/5678)
ISO 1585: Road vehicles — Test method for the measurement of fuel consumption
The Daewoo B12S3 was used across Daewoo's M150 platform with transverse mounting and later adopted by Chevrolet for global microcar applications. This engine received platform-specific adaptations-shorter intake manifolds in the Matiz and revised ECU mapping for automatic variants-and from 2005 the facelifted Matiz Classic introduced improved emissions calibration, creating partial interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front lower edge of the cylinder block, near the transmission bellhousing (Daewoo TIS B12-8801). The 8th VIN digit indicates engine type ('B' for B12 series). Pre-2004 models have silver valve covers with ribbed design; post-2004 units use black textured covers. Critical differentiation from B10S: B12S3 has larger bore and distinct intake manifold shape. Service parts require model year verification - timing kits for pre-2004 engines are not compatible with post-2004 tensioner revisions (Daewoo SIB DB-ENG-004).
The B12S3's primary reliability risk is timing belt failure on neglected units, with elevated incidence in warm climates and high-idle urban use. Internal Daewoo field reports from 2006 indicated a significant number of pre-2004 engines suffering belt-related damage beyond 60,000 km, while VCA MOT data shows increased catalytic converter failures in short-trip-driven vehicles. Infrequent servicing and low-quality belts increase failure probability, making adherence to replacement intervals and OEM specifications critical.
Analysis derived from Daewoo technical bulletins (2000-2008) and UK DVSA failure statistics (2005-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about DAEWOO B12S3.
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