Updated on 19 October, 2021
A Cylinder Leak Down Tester is an important tool used to detect the state of inner combustion engines by manually introducing compressed air within the cylinder, and then measuring the amount of gas that leaks out. This tool is used in many types of industrial applications including powering trains, turbines, engines at the power station, processing plants, printing presses and so on. The tool helps in reducing the strain on the engine thus increasing the efficiency of the engine. This also prevents the increase in wear and tear of the engine due to stress. Leakage of inner combustion engine parts can lead to catastrophic failures in engines like pistons, rings, bearings, connecting rods, timing chains etc. Hence, leak down testers are very essential tools.
It has an automatic air pressure gauge which displays the flow of air through the hose. A positive gauge shows the flow of air whereas a negative gauge shows the flow of gas escaping from the cylinder. A weak point in the Cylinder Leak Down Tester is its inability to display small leaks in the cylinder. In such cases it may only be able to detect the leakage of a few cc's. It has to be carried along with the Cylinder Leak Down Tester while purchasing the tool as it must be portable.
The Cylinder Leak Down Tester comes with many accessories. The first accessory is a flexible hose called the Gauge Link, which is useful for carrying the tester wherever you go. The next accessory is the air compression gauge, which is used for reading the compression test results of the engine cylinder. This gauge displays the pressure as well as the temperature of the cylinder before testing is done. In addition to these, the Cylinder Leak Down Tester also contains an LED light which gives accurate readings.
The Air Compression Gauge is one of the most important Cylinder Leak Down testers. The main function of this accessory is to monitor and control the cooling system of the car. As we all know, every car requires air and fuel to function properly. Hence, the air compression gauge helps to regulate the amount of intake and exhaust air. It helps to maintain the right level of compression of the engine thereby ensuring that there is no leakages in the system. There are various types of the air compression gauges available in the market.
One of the most commonly found accessories in a Cylinder Leak Down Tester is the air hold gauge. This accessory helps to check the amount of air hold (the space between the valve seat and the valve casing) remaining after the complete compression of the engine. If the air hold remains intact then it is an indication of leakages in the cylinder head and the seal. On the other hand, if the air hold is damaged then it can be an indication of a damaged valve stem, worn out seals, worn cylinder head, worn down cylinder heads or worn out seals.
The second type is the pressure sensitive valve. This Tester works on the principle of detecting pressure changes caused due to varying compression pressures. As per the requirement, it comes with a dial and a series of needles that display different compression pressures. The needles increase as the pressure decreases. The pressure sensitive valve monitors the compression pressure changing due to engine rotation and accordingly displays the readings.
For high-pressure Cylinder Leak Down Test, the best option is the spark plug close circuit detector. This accessory uses an electrical current to detect the opening and closing of the spark plug. The wires are attached to a small cap that forms a loop and the spark plugs open when the circuit is formed. Due to the increased electric voltage, the leakages show up as black marks on the screen. The leakages also show up as glow as the oxygen mixture is exhausted through the leak holes in the cylinder walls.
The third type is the fuel injector leakage detector. This device uses the principle of injecting fuel in the cylinder without causing any damage to the combustible materials. However, the leakage will form a black mark on the screen indicating the exact source of the leakage. This device is mainly used for low pressure Cylinder Leak Down Test.