Engine Auto Tensioner


Timing Chain Auto-tensioner

The timing chain auto-tensioner uses a spring and engine oil pressure to maintain proper tension at all times. It also suppresses noise from the timing chain. Using an internal ratchet device, the tensioner applies tension with a spring when there is no oil pressure at such times as engine starting.

Timing Belt Auto-tensioner

The timing belt auto-tensioner uses a spring force and sealed silicone oil pressure to maintain proper belt tension at all times.

EngineLubrication System

The lubrication system supplies engine oil to each engine part, creating a film of engine oil, which reduces the effects of friction and wear by allowing engine parts to slide smoothly and perform optimally. There are many rotating and sliding parts in an engine. As the engine operates at high engine speed, if these parts were not lubricated, a great amount of friction would occur, resulting in wear and seizure. To keep the engine rotating smoothly, the friction on each part needs to be minimized.

Oil Pump

The oil pump draws the engine oil from the oil pan and pumps it to each part of the engine. The driven rotor rotates along with the drive rotor, however because the driven rotor is eccentricity, the spacing between both rotors changes with rotation. This change of spacing is used to draw and pump the oil. There is a relief valve built into the oil pump, which releases at the specified pressure controlling the maximum oil pressure.


When the relief valve sticks, the oil pressure will fail to rise or rise abnormally causing lubricated parts to seizure or oil leaks to occur. Also, when the sliding parts inside the pump wear out, or the gasket or O-ring is damaged, this causes the oil pressure to drop.

Oil Filter

All of the oil pumped up by the oil pump passes through the oil filter where metallic particles from wear and carbon sludge are filtered out. The oil pushes open the check valve and enters the outer circumference of the element, where is filtered, and then is discharged from the center of the element. The check valve at the opening of the oil filter is designed to prevent contaminants, which have collected in the outer circumference of the element, from flowing back into the engine when the engine stops. If the filter element becomes clogged, the pressure difference occurs between the outer and inner circumference of the element and increases. When the pressure difference becomes the prescribed amount, the relief valve opens so that the oil does not pass through the element and is sent to the lubrication part. This prevents insufficient lubrication from occurring when the element is clogged. However the oil filter is required to be replaced periodically because the dirt oil is sent.

Oil Pressure Warning Lamp

The oil pressure warning lamp warns the driver when it detects abnormally low engine oil pressure. The oil pressure switch is mounted in the oil pan or the cylinder block and detects the pressure in the main oil gallery.

1. When the oil pressure is low [19.6 4.9 kPa (0.2 0.05 kgf/cm2) or lower]

When the engine is stopped or the pressure is lower than the specified amount, the point inside the oil pressure switch closes and the oil pressure warning lamp turns on. 2. When the oil pressure is high [19.6 4.9 kPa (0.2 0.05 kgf/cm2) or higher]

When the engine is started and the oil pressure surpasses the specified amount, the oil pressure pushes the diaphragm inside the oil pressure switch. As a result, the point opens and the oil pressure warning lamp turns off.


Normal oil pressure is between 0.5 and 5 kgf/cm2 . If the oil pressure goes below 0.2 kgf/ cm2 , the oil pressure warning lamp will turn on. If this lamp turns on, it means that there is some kind of abnormality in the lubrication system. Furthermore, just because the lamp is off, it is no guarantee that the engine has correct oil pressure at high engine speed. For that reason, some engines use an oil pressure gauge to display the oil pressure.


The low engine oil level warning lamp turns on when the amount of oil is extremely low.

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