General information about engines (Opel Astra G)

General diagram of the functioning of the lubrication system of engines used to equip Opel Astra/Zafira vehicles



The Opel Astra/Zafira model range is distinguished by an extremely wide range of engines offered to consumers. The full list of engines used to equip the models under consideration is given in Specifications at the beginning of this Chapter. Due to space limitations, this Guide presents to the readers' attention only some of the most typical representatives of each class of engines used, namely: a 1.6-liter SOHC 8-valve gasoline engine (manufacturer code X16SZR), a range of petrol 16-valve DOHC engines with a capacity of 1.4 to 2.0 liters (manufacturer codes X14XE, X16XEL, X18XE1 and X20XEV, a later modification of which was the X20XER engine used to equip Astra-OPS models); as well as 8-valve diesel engines with a volume of 1.7 l SOHC and DOHC (codes X17DTL and Y17DT respectively) and two turbocharged 16-valve SOHC 2.0L diesel engines (codes X20DTL/Y20DTL with low-pressure turbocharging and Y20DTH with high-pressure turbocharging). At the beginning of the Chapter are given Specifications with a detailed description of the technical characteristics of the listed engines.

Petrol engines 1.6L SOHC

In-line 4-cylinder 8-valve engine, with single overhead camshaft (SOHC). Mounted transversely at the front of the car. The transmission assembly is located to the left of the engine and transmits the torque developed by the latter to the front wheels of the car.

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The cylinder block is made of aluminum alloy and is equipped with dry-type liners.

Observe the prescribed tightening torques for threaded connections, as aluminum castings are soft materials and over-tightening component fasteners may damage the threaded holes!

The crankshaft rotates in five main bearings equipped with plain bearings. The thrust half rings regulating the axial play of the shaft are installed on the central (third) support of the shaft.

The connecting rods are mounted on the working journals of the crankshaft with friction bearings and horizontally split lower heads. The connecting rods are attached to the pistons by means of piston pins pressed into their upper heads — the pins have a floating fit in the pistons. The pistons, cast from aluminum, are equipped with three piston rings — two compression rings and one (lower) oil scraper ring.

The camshaft rotates in a bed mounted on top of the cylinder head and is driven from the crankshaft by means of a rubber toothed belt (the same belt is used to drive the water pump). The eccentric cams of the camshaft act on the valve drive levers, the working ends of which rest against the ends of the spring-loaded valve stems inserted into the guide bushings and equipped with oil-deflecting caps. The opposite ends of the levers rest against hydraulic compensators, which automatically select the valve clearances.



The engine lubrication system is powered by a gear oil pump driven by the crankshaft journal. Oil is drawn in through a mesh-filtered oil intake from the engine oil pan and is filtered by a full-flow replaceable oil filter. Oil moves through oil flows provided in the block casting and is distributed in two main directions: to the crankshaft and camshaft bearings. Oil is supplied to the bearings under pressure through special holes in the shaft bodies. Lubrication of the camshaft cams and valve components, as well as other internal engine components, is carried out by splashing.

Typical diagram of the functioning of the lubrication system - see illustration General diagram of the functioning of the lubrication system of engines used to equip Opel Astra/Zafira vehicles.

The crankcase gases are removed from the engine block using a semi-closed ventilation system. The gases are removed through the timing cover and enter the intake manifold via a special hose.

Petrol engines 1.4-2.0 l DOHC

The engine is a 4-cylinder in-line, 16-valve, equipped with two overhead camshafts (DOHC), mounted transversely at the front of the car. The drive is carried out to the front wheels by means of a transmission assembly mounted on the left side of the engine.

Some 2.0 engines are equipped with a balancer assembly consisting of two additional shafts, which reduces the intensity of vibrations associated with the operation of the crankshaft. The assembly is installed between the cylinder block and the oil pan (for more details, see. Removal, installation and adjustment of the crankshaft balancing mechanism (2.0L engines).



The design of the cylinder block and connecting rod and piston groups is similar to that described above for SOHC engines.

Both camshafts rotate in the cylinder head and are driven from the crankshaft by a rubber toothed belt, which also serves to drive the water pump. The intake and exhaust valves are driven directly from the eccentric cams of the corresponding camshafts via tappets equipped with hydraulic valve clearance compensators.

The operation of the lubrication and crankcase ventilation systems is also similar to that described above for SOHC engines.

Diesel engines 1.7L SOHC

The engine is a 4-cylinder in-line, 8-valve, single overhead camshaft (SOHC) engine mounted transversely at the front of the vehicle. The transmission assembly is attached to the engine on the left and transmits torque to the front wheels.

The cylinder block is manufactured using cast iron casting with cylinders molded directly into its body (dry sleeve block).

The crankshaft rotates in five main bearings equipped with plain bearings. The thrust half rings regulating the axial play of the shaft are seated in the upper half of the central (third) support. A distinctive feature of this engine is the use of a cast coupling of the crankshaft supports.

The connecting rods are mounted on the shaft with their lower horizontally split heads, equipped with plain bearings. The cast aluminum pistons are connected to the connecting rods by means of piston pins, freely floating in the upper heads of the connecting rods and secured in the piston bosses with retaining rings. Each piston is equipped with three piston rings - two compression rings and one (lower) oil scraper ring.



The intake and exhaust valves are spring-loaded and move in guide bushings pressed into the cylinder head. The camshaft is driven from the crankshaft by means of a toothed belt and rotates directly in the cylinder head. The valves are driven from the camshaft by means of drive levers installed directly under the cams. Valve clearances are adjusted automatically by equipping the support posts of the drive levers with hydraulic compensators.

The lubrication system is organized similarly to that described above for gasoline engines, with the only difference being that in order to increase the intensity of piston bottom cooling, an oil sprayer is installed at the base of each cylinder in the block. To maintain normal oil temperature under increased loads, the engine is additionally equipped with an oil cooler.

Diesel engines 1.7L DOHC

The engine is a 4-cylinder in-line, 16-valve, equipped with two overhead camshafts (DOHC), mounted transversely at the front of the car. The drive is carried out to the front wheels by means of a transmission assembly mounted on the left side of the engine.

The design of the cylinder block and connecting rod and piston groups is similar to that described above for 1.7 l SOHC engines, excluding the crankshaft main bearing clamp.

The intake camshaft rotates in the valve timing housing and is driven by a toothed belt transmission directly from the crankshaft. The exhaust camshaft is driven by a gear transmission from the intake shaft.

The camshafts act on the valve stems placed in the guide bushings through tappets equipped with adjusting washers. Valve clearances are set manually by selecting washers of the required thickness.



The lubrication system is organized similarly to that described above for gasoline engines. In order to maintain normal oil temperature under increased loads, the engine is additionally equipped with an oil cooler.

Diesel engines 2.0L SOHC

The 2.0-liter (1994 cc) engine is one of the latest developments from Opel and is a 4-cylinder in-line, 16-valve design with a single overhead camshaft (SOHC). The engine is mounted transversely at the front of the car, with the transmission assembly connected to the left, transmitting torque to the front drive wheels.

The crankshaft rotates in five main bearing supports. The support half rings, which regulate the amount of axial play of the shaft, are installed in the third support.

The connecting rods are mounted on the crankshaft journals with horizontally split and equipped with plain bearing liners by the lower heads. The piston pins have a floating fit in the upper heads of the connecting rods and are secured with retaining rings in the bosses on the piston walls. The pistons, cast from aluminum, are equipped with three piston rings: two compression rings and one (lower) oil scraper ring.

The cylinder block is cast from grey cast iron. The cylinders form a single unit with the block (dry cartridges).

The intake and exhaust valves are spring-loaded and move in guide bushings pressed into the cylinder head.

The camshaft is driven from the crankshaft by means of a two-row chain drive: the lower chain drives the high-pressure fuel pump (HPFP) directly from the crankshaft, the upper chain drives the camshaft from the upper chain ensures rotation of the camshaft from the HPFP.



The single camshaft rotates directly in the cylinder head and drives sixteen via drive levers and hydraulically compensator-equipped tappets. The valve drive levers are mounted directly under the cams and each drive two valves. Valve clearances are adjusted automatically.

The lubrication system is organized similarly to that described above for the 1.7 l engine.

All engines

List of repair works performed without removing the engine from the car

The following repairs can be performed without removing the engine from the vehicle:

1. Compression check;

2. Removing and installing the timing cover;

3. Removing and installing the timing belt cover;

4. Removing and installing timing drive components (belt/chains, gears/sprockets);

5. Removal and installation of the timing belt/chain tensioner and chain guides diesel engines (2.0L engines);

6. Removing and installing the camshaft and valve drive levers/tappets);

7. Adjusting valve clearances (diesel engines 1.7 l DOHC);

8. Removing and installing the cylinder head;

9. Removing and installing pistons with connecting rods *;

10. Removing and installing the oil pan;

11. Removal, repair and installation of the oil pump;

12. Removing and installing the oil cooler (with appropriate equipment);

13. Replacing the crankshaft seals;

14. Checking the condition and replacing the powertrain suspension supports;

15. Removing, checking condition and installing flywheel/drive disk

* Although after removing the cylinder head and the pan (without removing the engine) the possibility of dismantling the connecting rod and piston assemblies appears, this opportunity should not be abused due to the difficulties associated with the need to maintain cleanliness and carry out a number of preparatory procedures. In view of the above, a description of this procedure see. General and major engine repairs.



Before starting work, thoroughly clean the engine compartment and the outer surfaces of the power unit using one of a wide range of special solvents. This treatment will prevent dirt from getting inside the engine.

If necessary, depending on the nature of the work to be done, the bonnet can be removed to provide free access to the components to be serviced (see Chapter Body), - to avoid accidental damage to the paintwork, cover the car fenders with special covers or just old blankets.