Checking the compression in the cylinders (Nissan Primera P10)

If it is assumed that the required pressure is not created in the cylinder, it can be checked with a compression gauge. To check, unscrew the spark plugs, insert the compression gauge into the corresponding hole in the spark plug and turn on the starter. The device indicator gives a compression value. Thanks to this, leaky valves, pistons or piston rings are detected. If the engine is still fairly new, the compression value should be within the values from Specifications.

The specified wear limits should not be underestimated. If the compression is low, you should consider installing another engine or repairing it. It is also very important whether one cylinder has insufficient compression or all. If, for example, the compression in one cylinder differs by 1.0 bar, it may be that the cylinder valves are stuck and only the cylinder head, i.e. the valves, needs to be repaired. It may also be that the piston rings are stuck and gases along the piston are escaping into the crankcase. If the compression improves when adding a small amount of oil to the cylinders, this is a sign of piston ring wear. With uniform loss of compression, in most cases the cylinders are worn.

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