The Vauxhall Astra Mk V Convertible 1.8, produced between 2006 and 2011, represented a key offering in the Astra Mk V range, specifically the convertible body style. Based on the Astra H platform (internally designated as A04), this variant aimed to provide open-top motoring with a balance of performance and affordability. Positioned as a mid-range option within the convertible lineup, it slotted between the lower-powered 1.6-liter models and the more potent 2.0-liter turbocharged versions. The Astra Mk V Convertible was primarily marketed in Europe, offering a stylish alternative to rivals like the Peugeot 308 CC and Renault Megane Coupe Cabriolet.
Technical Specifications
| Brand | Vauxhall |
| Model | Astra |
| Generation | Astra Mk V Convertible |
| Type (Engine) | 1.8 (140 Hp) |
| Start of production | 2006 |
| End of production | 2011 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe – Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (economy) – urban | 10.3 l/100 km (22.8 US mpg, 27.4 UK mpg, 9.7 km/l) |
| Fuel consumption (economy) – extra urban | 6.2 l/100 km (37.9 US mpg, 45.6 UK mpg, 16.1 km/l) |
| Fuel consumption (economy) – combined | 7.7 l/100 km (30.5 US mpg, 36.7 UK mpg, 13 km/l) |
| CO2 emissions | 185 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 10.7 sec |
| Acceleration 0 – 62 mph | 10.7 sec |
| Acceleration 0 – 60 mph | 10.2 sec |
| Maximum speed | 209 km/h (129.87 mph) |
| Emission standard | Euro 4 |
| Weight-to-power ratio | 11.1 kg/Hp, 90 Hp/tonne |
| Weight-to-torque ratio | 8.9 kg/Nm, 112.5 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 | 6.1 l (6.45 US qt | 5.37 UK qt) |
| Kerb Weight | 1556 kg (3430.39 lbs.) |
| Max. weight | 1865 kg (4111.62 lbs.) |
| Max load | 309 kg (681.23 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 | 5 gears, manual transmission |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Tires size | 225/45 R17 |
| Wheel rims size | 17 |
Powertrain & Engine Architecture
The Astra Mk V Convertible 1.8 utilized the Z18XER engine, a 1.8-liter inline-four cylinder gasoline engine. This engine was a member of Vauxhall/Opel’s ‘Ecotec’ family, known for its relatively lightweight construction and focus on efficiency. The Z18XER featured multi-port fuel injection and a dual overhead camshaft (DOHC) valvetrain with four valves per cylinder. This configuration allowed for good breathing and contributed to the engine’s 140 horsepower output at 6400 rpm and 175 Nm (129 lb-ft) of torque at 3800 rpm. The engine’s block was constructed from cast iron, while the cylinder head was made of aluminum. The 5-speed manual transmission was the standard offering, providing a balance between fuel economy and driver engagement. The transmission featured typical front-wheel-drive configuration with a cable-operated shift mechanism.
Driving Characteristics
The 1.8-liter engine, paired with the 5-speed manual transmission, provided adequate performance for everyday driving. Acceleration from 0-60 mph took around 10.2 seconds, and the top speed was approximately 129.87 mph. While not a sports car, the 1.8 offered sufficient power for overtaking maneuvers and cruising on motorways. Compared to the higher-output 2.0-liter turbocharged models, the 1.8 felt less responsive, particularly at higher speeds. However, the 1.8’s lighter weight and more balanced chassis contributed to a more nimble feel in corners. The gear ratios were tuned for fuel efficiency, meaning the engine often needed to be revved to access its full power potential. The manual transmission offered a more engaging driving experience than the optional automatic, which could feel sluggish and detract from the overall driving enjoyment.
Equipment & Trim Levels
The Astra Mk V Convertible 1.8 typically came with a reasonable level of standard equipment. This included central locking, electric front windows, a CD stereo, and alloy wheels. Higher trim levels, such as the Design or SE, added features like air conditioning, rain-sensing wipers, and upgraded interior trim. Interior upholstery was typically cloth, with leather options available as an extra cost. The dashboard layout was functional and straightforward, with a clear instrument cluster and easy-to-use controls. Optional extras included a panoramic sunroof, heated seats, and a premium sound system.
Chassis & Braking
The Astra Mk V Convertible utilized a MacPherson strut front suspension and a torsion beam rear suspension. This setup provided a good compromise between ride comfort and handling. The front suspension featured a stabilizer bar to reduce body roll during cornering. Braking duties were handled by ventilated discs at the front and solid discs at the rear. Anti-lock Braking System (ABS) was standard. The steering was power-assisted, providing light and precise control. The convertible’s chassis was reinforced compared to the standard Astra hatchback to compensate for the lack of a fixed roof, improving torsional rigidity.
Market Reception & Comparison
The Astra Mk V Convertible 1.8 was generally well-received by automotive critics as an affordable and stylish open-top option. It was praised for its comfortable ride and decent fuel economy (around 30.5 US mpg combined). However, some reviewers noted that the 1.8-liter engine felt underpowered compared to its rivals, particularly when the car was fully loaded. Compared to the 2.0-liter turbocharged models, the 1.8 offered a lower purchase price and lower running costs, but at the expense of performance. The 1.8 was often seen as a good choice for drivers who prioritized style and comfort over outright speed.
Legacy
The Z18XER engine, while generally reliable, is known to be susceptible to oil leaks over time, particularly around the valve cover gasket and oil cooler seals. Regular maintenance, including oil changes and coolant flushes, is crucial for ensuring long-term reliability. The Astra Mk V Convertible 1.8 remains a relatively affordable used car option today. Its open-top design and stylish looks continue to appeal to buyers looking for a fun and practical convertible. However, potential buyers should be aware of the potential for oil leaks and ensure that the car has been well-maintained.
