General information
This chapter describes the most common and important engine maintenance and repair procedures, with the exception of those requiring special skills and tools, such as engine overhaul procedures, which should be entrusted to a car service specialist.
The cars in question are equipped with 4-cylinder petrol engines of 1.0, 1.2 or 1.4 liters. Engines are DOHC (with two overhead camshafts and two valves per cylinder).
But the piston has 2 compression rings and one oil scraper ring.
The crankshaft is located in five main bearings.
The cylinder head is bolted to the block.
Two camshafts are located in the cylinder head and drive the valves through rocker arms mounted on pushers with hydraulic valve clearance compensators. The rocker arms transmit motion to the valves through rollers with needle bearings. The camshafts are driven from the crankshaft through a chain.
The oil pump is located in the front cover of the cylinder block and is driven directly from the crankshaft.
Components and diagram of the engine lubrication system
Preparatory operations
Before carrying out any engine maintenance procedures, clean the engine compartment and the external surfaces of the power unit using a special solvent. This treatment will prevent dirt from getting inside the engine.
If necessary, depending on the nature of the work ahead, the hood can be removed in order to provide freedom of access to the components to be serviced (see chapter Body). To prevent accidental damage to the paintwork, cover the fenders of the car with special covers or old blankets.
Excessive consumption of engine oil can be considered a signal to check the condition of the piston rings, valve stem seals and / or valve guides. Naturally, first of all, you should make sure that oil losses are not associated with the development of its external leaks. Check cylinder compression (see Section Compression pressure test), to determine the general condition of the engine.
Loss of developed power, rev stability, excessive valve train noise and increased fuel consumption are usually fairly common signs that an engine needs an engine overhaul, especially when all of these factors occur at the same time. If performing a full range of adjustments does not resolve the issue, the only recourse is to perform a general mechanical rebuild on the engine.
The overhaul of the power unit involves the restoration of all its operating parameters to the level characteristic of the new engine. During the overhaul, it is mandatory to replace the piston rings and restore the cylinder mirrors (turning and/or honing). Usually, the main and connecting rod bearings of the crankshaft are replaced, if necessary, turning and restoring its necks can be made. It is mandatory to service the valves, the condition of which at the time of the need for an overhaul of the engine almost certainly leaves much to be desired. In parallel with the general repair of the power unit, reconditioning of the starter and generator is also usually carried out.
Critical cooling system components such as hoses, drive belts and thermostat must be replaced with new ones during engine overhauls. In addition, you should carefully check the condition of the radiator (see chapters Vehicle settings and routine maintenance and Engine cooling, heating, ventilation and air conditioning systems). If there are signs of leaks or obstruction, the radiator should be replaced. Don't forget to check the condition of the oil pump as well.
Overhaul of the engine does not require high professional training from the performer, but it takes a lot of time. You should plan to stop using the car for at least two weeks, especially if you need help from a mechanic shop to carry out some restoration work.
Most of the work can be done with the usual set of hand tools, however some of the checks to determine the suitability of individual components for further use require the use of precision measuring equipment. In doubtful situations, seek help from service station specialists.
Do not forget that the decisive factor in the question of the advisability of overhauling the engine is the condition of its cylinder block. It is often cheaper and more reliable to replace a worn engine with a remanufactured one.
In conclusion, it can be seen that all efforts to carry out the refurbishment of worn components will be wasted if careless attention is paid to the requirement of cleanliness during assembly of the unit.