Washington DC Area Ford Dealer Shows You How to Check Engine Cylinders

Aug 09, 2017 - 1 minute read

Washington DC Area Ford Dealer Shows You How to Check Engine Cylinders

If you have been noticing that your vehicle has been running roughly or hasn’t been as powerful as usual, there may be an issue with one or more cylinders. If it is believed that pressure is escaping from the engine, you must check the compression in the cylinders with a compression gauge. A compression gauge measures the the amount of pressure each piston exerts on the fuel/air mixture before the spark plug fires the mixture.


Our Washington DC area Ford service center is here to give you some tips on how to check engine cylinders. While this task is cost effective and quick to do, many shoppers are unaware of how to complete it. Below are steps on how to use a compression gauge to check to see if there are any issues with the engine cylinders in your car:


  1. Have someone sit in the driver’s seat while the car is in Neutral or Park, with the engine off and the parking brake on.

  2. Depending on which distributor you have, follow the necessary step below:

    • If you have a vehicle with a distributor, be sure to pull the big wire that leads to the coil from the distributor cap. Then, lean the metal connector against an unpainted metal surface as far away from the spark plugs as possible.

    • If your vehicle has a distributorless ignition, make sure you disconnect the electrical connector at the ignition module. If you are unsure what to disconnect, ask a mechanic and trained professional.

  3. In order to ensure the gasoline mist won’t spray out of the spark plug holes, disable the fuel injection system.

  4. Be sure you label and remove the boots that connect each spark plug wire and each spark plug, as mixing up these wires can really mess up your engine. Once removed, lay down in a clean place.

  5. Connect the starter switch to the battery.

  6. Insert the compression gauge. This should fit where the first spark plug screwed into the cylinder. Our Ford parts department serving Washington DC can help you get a compression gauge, as well as help you find any other parts you may need.

  7. Have a friend turn on your engine ignition, or use a remote starter switch, and let the engine crank over about six ties.

  8. Write down the reading in pounds per square inch (PSI) and then reset the gauge.

  9. Repeat steps for each cylinder.

  10. Look at and assess the readings.

  11. Replace each spark plug in the cylinder it came from.


After looking at the results, the highest and lowest shouldn’t differ by more than 15 percent. If one or more cylinders have a reading that is well below the others, odds are the valves are either worn down or are out of adjustment. To see if the rings on the piston are worn out, add motor oil down the spark plug and retest the compression.


If the reading rises a bit after this, your ride probably needs new rings on the piston in the cylinder. After all is said and done, if the gauges show a pressure of less than 100-PSI, there is something wrong with the cylinder.


To learn more about how we can help with all of your service needs, be sure to contact Apple Ford Lincoln by calling us at (866) 695-6642.