How to Perform a Compression Test on the Engine in a Honda CR-Vby Contributor
The Honda CR-V is a compact SUV containing a 4-cylinder engine. One of the advantages of owning this compact model instead of a full-size SUV is better gas mileage, so it is important to keep the smaller 4-cylinder engine running properly. If the Honda CR-V burns oil or loses power, a compression test is a simple, affordable way to find out what is wrong without tearing apart the engine.
Prepare for the compression test by warming up the engine in the Honda CR-V. Performing a compression test on a cold engine will produce inaccurate results. Make sure the battery is in good shape since it will need to spin the engine many times during the test.
Begin by removing all four spark plugs from the engine and disabling the ignition system. This will prevent electrical shock while performing the test. The engine can now spin freely.
Place the compression tester in one of the spark plug holes and crank the starter. This rotates the engine and builds compression in the cylinder. Record the compression number and continue to the next spark plug hole. Repeat the process until you test all four cylinders and record the compression numbers.
Evaluate the test results by comparing these four numbers to recommended manufacturer specifications. If the Honda CR-V is a 2007 or a 2008 model, the compression ratio is 9.7:1. For model years between 1999 and 2006, the ratio is 9.6:1. If the SUV is one of the earliest models, 1997 or 1998, the ideal ratio is 9.0:1. Compression numbers should be within 15 PSI of these suggested ratios.
Compare the compression numbers to see if they are within 10 PSI of each other. If any cylinder has a low reading, perform the compression test again after adding a small amount of motor oil to that cylinder. If the compression number increases, worn piston rings or cylinder walls are present. Worn valves or valve seats are the problem if the number does not change.
Items you will need
- Compression tester
- Motor oil