Opel Z18XER

Opel Z18XERThe Opel Z18XER is a 1.8 l (1,796 cc, 109.6 cu-in) straight-four four-stroke natural aspirated gasoline engine from the third generation of GM Family 1. The engine was developed by Opel (a subsidiary of General Motors) and manufactured since 2005.

The Opel Z18XER engine uses a cast grey iron block with five-bearings crankshaft and aluminum head with dual overhead camshafts (DOHC) and four valves per cylinder (16 valves in total). The engine is equipped with a sequential fuel injection system, double continuous variable cam phasing (DCVCP) and electronic ignition system.

Cylinder bore and piston stroke are 80.5 mm (3.17 in) and 88.2 mm (3.47 in), respectively and compression ratio rating is 10.5:1. The Z18XER engine produces 140 PS (103 лW; 138 HP) at 6,300 rpm of maximum horsepower and 175 Nm (17.8 kg·m; 129.1 ft·lb) at 3,800 rpm of maximum torque. Redline is 6,500 rpm.

The breakdown of the engine code is as follows:

  • Z – Euro 4 engine
  • 18 – 1.8 Liter displacement
  • X – Comression ratio from 10 to 11.5:1
  • E – Multi Point Fuel Injection system
  • R – Power is increased compared to Z18XE

General information

Engine Specifications
Engine codeZ18XER
LayoutFour stroke, Inline-4 (Straight-4)
Fuel typeGasoline (petrol)
Production2005-
Displacement1.8 L, 1,796 cm3 (109.6 cu in)
Fuel systemSequential fuel injection
Power adderNone
Power output140 PS (103 KW; 138 HP) at 6,300 rpm
Torque output175 Nm (17.8 kg·m; 129.1 ft·lb) at 3,800 rpm
Firing order1-3-4-2
Dimensions (L x W x H):
Weight119 kg (262 lbs)

Cylinder block

The Z18XER cylinder block is based on the proven hollow-frame concept. Gray cast iron provides an extremely durable foundation, optimized with a deep skirt that minimizes both wear and vibration. Pistons apply a floating-pin design. The wrist pins, which attach the piston to the connecting rod, “float” inside the rod bushing and pin bores in the piston barrel. Pistons also have oil-spray cooling. Each piston has its own individual directed jet that sprays oil toward its skirt, coating its underside and the cylinder wall with an additional layer of lubricant.

Cylinder block
Cylinder block alloyCast-iron
Compression ratio:10.5:1
Cylinder bore:80.5 mm (3.17 in)
Piston stroke:88.2 mm (3.47 in)
Number of piston rings (compression / oil):2 / 1
Cylinder inner diameter (standard):80.492-80.508 mm (3.169-3.1696 in)
Piston skirt diameter (standard):80.455-80.465 mm (3.1675-3.1679 in)
Piston pin outer diameter:19.000 mm (0.748 in)
Piston ring side clearance:Top0.040-0.080 mm (0.0016-0.0031 in)
Second0.030-0.070 mm (0.0012-0.0028 in)
Oil0.030-0.130 mm (0.0012-0.0051 in)
Piston ring end gap:Top0.20-0.40 mm (0.0079-0.0157 in)
Second0.40-0.60 mm (0.0157-0.0236 in)
Oil0.25-0.75 mm (0.0098-0.0295 in)
Crankshaft journal diameter:54.980-54.997 mm (2.1646-2.1652 in)
Crankpin diameter:42.971-42.987 mm (1.6918-1.6924 in)

Connecting rod bearing cap bolt tightening procedure and torque specs:

  • Step 1: 35 Nm (3.6 kg·m; 25.8 ft·lb)
  • Step 2: Turn all bolts 45°
  • Step 3: Turn all bolts 15°

Crankshaft Bearing Cap Bolt:

  • Step 1: 50 Nm (5.1 kg·m; 36.9 ft·lb)
  • Step 2: Turn all bolts 45°
  • Step 3: Turn all bolts 15°

Cylinder head

The cylinder head is made of an aluminum alloy. The Z18XER engine has Double Continuous Variable Cam Phasing (DCVCP) on the intake and exhaust sides. The camshafts are driven by timing belt. The engine has a composite intake manifold and fabricated stainless steel maniverter 4-1 with a close-coupled catalyst.

Cylinder head (after 2006)
Valve Arrangement:DOHC, belt driven
Valves:16 (4 valves per cylinder)
Valve head diameter:INTAKE31.1-31.3 mm (1.2244-1.2323 in)
EXHAUST27.4-27.6 mm (1.0787-1.0866 in)
Valve length:INTAKE101.65 mm (4.002 in)
EXHAUST102.46 mm (4.034 in)
Valve stem diameter:INTAKE4.965-4.980 mm (0.1955-0.1961 in)
EXHAUST4.950-4.965 mm (0.1949-0.1955 in)
Valve spring free length:41.6 mm (1.6378 in)
Cam stroke:INTAKE9.3 mm (0.3661 in)
EXHAUST8.3 mm (0.3268 in)

Head tightening procedure and torque specs:

  • Step 1: 25 Nm; 2.5 kg·m; 18.5 ft·lb)
  • Step 2: Turn all bolts 90°
  • Step 3: Turn all bolts 90°
  • Step 4: Turn all bolts 90°
  • Step 5: Turn all bolts 45°

Maintenance data

Valve clearance (Cold)
Intake valve0.21-0.29 mm (0.008-0.011 in)
Exhaust valve0.27-0.35 mm (0.010-0.014 in)
Compression pressure
Standard16.0 kg/m2
Minimun14.0 kg/m2
Compression differential limit between cylinders0.1 kg/m2
Oil system
Oil consumption , L/1000 km (qt. per miles)up to 0.5 (1 qt. per 1200 miles)
Recommended engine oil 0W-20, 5W-30
Oil typeGM-LL-A-025
Engine oil capacity (Refill capacity) With filter change 4.5 l
Without filter change 4.3 l
Oil change interval, km (miles)10,000 (6,000)
Ignition system
Spark plugBosch: FQR8LEU2
Spark plug gap0.85-0.95 mm (0.034-0.037 in)
Spark plug tightening torque25 Nm (2.55 kg·m; 18.45 ft·lb)

Vehicle applications

ModelYears Produced
Alfa Romeo 159 1.8 JTS2005-2010
Fiat Croma 1.8 16v2005-2010
Opel Astra H 1.8 16v2006-2010
Opel Astra H 1.8 16v2006-2010
Opel Vectra C 1.8 16v2005-2008
Opel Signum 1.8 16v2006-2008
Opel Zafira B 1.8 16v Ecotec2005-2010
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We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.

3 Comments

  1. What’s the difference between the x18xe-1 and the x1z18xe?
    I had to replace my z18 as the water pump died and killed the motor. Wreckers sold me the x18 engine. I see that I can swap the inlet manifold and exhaust manifold.
    Cheers Sav

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