The Vauxhall Astra Mk V Convertible 1.8 (140 hp) Automatic, produced between 2006 and 2011, represented a compelling entry point into the convertible market for buyers seeking a stylish and relatively affordable open-top experience. Positioned within the broader Astra Mk V Convertible range – which included various engine and transmission options – this variant aimed to balance performance with ease of use, targeting drivers who prioritized comfort and convenience over outright sporting prowess. It was part of the H-series Astra, a generation that saw significant advancements in design and technology for the brand, and shared its platform (the GM Delta platform) with other Opel/Vauxhall and Chevrolet models.
Technical Specifications
| Brand | Vauxhall |
| Model | Astra |
| Generation | Astra Mk V Convertible |
| Type (Engine) | 1.8 (140 Hp) Automatic |
| Start of production | 2006 |
| End of production | 2011 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe – Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 10.8 l/100 km (21.8 US mpg, 26.2 UK mpg, 9.3 km/l) |
| Fuel consumption (extra urban) | 6.5 l/100 km (36.2 US mpg, 43.5 UK mpg, 15.4 km/l) |
| Fuel consumption (combined) | 8.1 l/100 km (29 US mpg, 34.9 UK mpg, 12.3 km/l) |
| CO2 emissions | 194 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 12.7 sec |
| Acceleration 0 – 62 mph | 12.7 sec |
| Acceleration 0 – 60 mph | 12.1 sec |
| Maximum speed | 188 km/h (116.82 mph) |
| Emission standard | Euro 4 |
| Weight-to-power ratio | 11.2 kg/Hp, 89.2 Hp/tonne |
| Weight-to-torque ratio | 9 kg/Nm, 111.5 Nm/tonne |
| Power | 140 Hp @ 6400 rpm |
| Power per litre | 78 Hp/l |
| Torque | 175 Nm @ 3800 rpm (129.07 lb.-ft. @ 3800 rpm) |
| Engine layout | Front, Transverse |
| Engine Model/Code | Z18XER |
| Engine displacement | 1796 cm3 (109.6 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Cylinder Bore | 80.5 mm (3.17 in.) |
| Piston Stroke | 88.2 mm (3.47 in.) |
| Compression ratio | 10.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Engine oil capacity | 4.25 l (4.49 US qt | 3.74 UK qt) |
| Coolant capacity | 6.1 l (6.45 US qt | 5.37 UK qt) |
| Kerb Weight | 1570 kg (3461.26 lbs.) |
| Max. weight | 1900 kg (4188.78 lbs.) |
| Max load | 330 kg (727.53 lbs.) |
| Trunk (boot) space – minimum | 205 l (7.24 cu. ft.) |
| Trunk (boot) space – maximum | 440 l (15.54 cu. ft.) |
| Fuel tank capacity | 52 l (13.74 US gal | 11.44 UK gal) |
| Length | 4476 mm (176.22 in.) |
| Width | 1759 mm (69.25 in.) |
| Width including mirrors | 2021 mm (79.57 in.) |
| Height | 1411 mm (55.55 in.) |
| Wheelbase | 2614 mm (102.91 in.) |
| Front track | 1491 mm (58.7 in.) |
| Rear (Back) track | 1481 mm (58.31 in.) |
| Ride height (ground clearance) | 130 mm (5.12 in.) |
| Drag coefficient (Cd) | 0.31 |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the front wheels of the vehicle. |
| Drive wheel | Front wheel drive |
| Number of gears and type of gearbox | 4 gears, automatic transmission |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Tires size | 225/45 R17 |
| Wheel rims size | 17 |
Powertrain & Engine Architecture
At the heart of the Astra Mk V Convertible 1.8 Automatic lies the Z18XER engine, a 1.8-liter inline-four cylinder petrol engine. This engine is a member of Vauxhall/Opel’s ‘Family 1’ engine family, known for its relatively simple design and robust construction. The Z18XER utilizes multi-point fuel injection and a dual overhead camshaft (DOHC) valvetrain with four valves per cylinder, contributing to its respectable power output for its displacement. The engine produces 140 horsepower at 6400 rpm and 175 Nm (129 lb-ft) of torque at 3800 rpm. Paired with this engine is a four-speed automatic transmission, which was a common choice for drivers prioritizing ease of use over manual control. This transmission, while providing smooth shifts, wasn’t known for its particularly quick response or fuel efficiency compared to more modern automatic gearboxes.
Driving Characteristics
The 1.8-liter engine and four-speed automatic combination delivered a comfortable, if not particularly exhilarating, driving experience. Acceleration from 0-60 mph took around 12.1 seconds, and the top speed was approximately 117 mph. The automatic transmission’s gear ratios were tuned for smooth cruising rather than aggressive acceleration. Compared to the more powerful 2.0-liter Turbo variants, the 1.8 Automatic felt noticeably slower, especially during overtaking maneuvers. However, it offered a more relaxed driving experience, particularly in urban environments. The relatively low torque output meant the engine needed to be revved to access its power, which could become noticeable on inclines or when carrying a full load of passengers and luggage.
Equipment & Trim Levels
The Astra Mk V Convertible 1.8 Automatic typically came equipped with a reasonable level of standard features. These included air conditioning, electric front windows, central locking, and a basic audio system. Higher trim levels, such as Design or Sport, added features like alloy wheels, upgraded upholstery, a multi-function steering wheel, and optional extras like a CD changer or a more advanced audio system. The convertible top was electrically operated, adding to the convenience. Interior upholstery was generally cloth, with leather options available as an upgrade. Dashboard design was functional and straightforward, typical of Vauxhall/Opel interiors of the period.
Chassis & Braking
The Astra Mk V Convertible utilized a MacPherson strut front suspension and a torsion beam rear suspension. This setup provided a reasonable balance between ride comfort and handling. Braking was handled by ventilated discs on the front wheels and solid discs on the rear. Anti-lock Braking System (ABS) was standard. The chassis was reinforced to compensate for the lack of a fixed roof, adding weight but maintaining structural rigidity. Stabilizer bars were fitted to both the front and rear axles to reduce body roll during cornering.
Market Reception & Comparison
The Astra Mk V Convertible 1.8 Automatic was generally well-received as an affordable and stylish convertible. Critics praised its comfortable ride and ease of use, but noted its relatively modest performance compared to some rivals. Fuel economy was average for its class, and reliability was generally good, although some owners reported minor issues with the electrical system. Compared to the more powerful 2.0-liter Turbo models, the 1.8 Automatic offered a lower price point and lower running costs, making it an attractive option for budget-conscious buyers. The 1.9 CDTi diesel variant offered significantly better fuel economy, but at the expense of refinement and driving enjoyment.
Legacy
The Astra Mk V Convertible 1.8 Automatic remains a relatively common sight on the used car market. The Z18XER engine is known for its durability, and with regular maintenance, it can provide many years of reliable service. However, potential buyers should be aware of the age-related issues common to older vehicles, such as corrosion and wear and tear on suspension components. The four-speed automatic transmission, while generally reliable, may exhibit signs of wear and tear after high mileage. Overall, the Astra Mk V Convertible 1.8 Automatic represents a good value proposition for those seeking an affordable and enjoyable open-top motoring experience.
