When the four-cylinder engine in a Nissan Sentra runs poorly, loses ability or burns oil, a compression elimination is a manageable idea of diagnosing the doubt. Birth by warming up the engine in the Nissan Sentra, by reason of a crisp engine Testament constitute inaccurate results. Once it is balmy, turn off the engine and disable the ignition course to avoid electrical shock during the compression test.2.
By comparing the compression numbers to the recommended compression ratio, you can figure absent which cylinders cover worn parts and charge repair.
Instructions
1.Remove the four spark plugs from the engine. Check to see if they are oily or damaged, since these are signs of trouble within the cylinder. Insert the compression tester into one of the spark plug holes and crank the starter. Rotating the engine builds compression in the cylinder.
3. Record the compression number and repeat the procedure on each of the cylinders. There will be four compression numbers when you are done. Compare them to see if they fall within 10 PSI of each other. You need to retest any cylinders with a low reading.
4. Compare the readings to manufacturer specifications. The compression ratio for a Nissan Sentra is 9.5:1. Compression numbers should fall within 15 PSI of this number.
5. Add a capful of motor oil to any cylinder with a low compression number before retesting. If the oil causes the number to increase, the engine has worn piston rings or cylinder walls. If the number stays the same, the cylinder has worn valves or valve seats instead.
