Testing the engine compression on the 2.4L engine in the Chrysler Sebring and Dodge Stratus is a breeze.
What makes testing the engine compression on this engine easy is the fact that the spark plugs are very easy to remove.
In this tutorial, I'll explain how to do the compression test and more importantly how to interpret your test results to find out if there is a problem or not.
The entire testing procedure is explained in detail so that you can get to the bottom of the engine compression issue you're trying to troubleshoot.
Contents of this tutorial at a glance:
APPLIES TO: Quite a few Chrysler, Dodge, and Plymouth vehicles are equipped with the 2.4L 4 cylinder engine. This tutorial applies to the following vehicles:
- 2.4L Chrysler Cirrus: 1995, 1996, 1997, 1998, 1999, 2000
- 2.4L Chrysler PT Cruiser: 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
- 2.4L Chrysler Sebring: 2001, 2002, 2003, 2004, 2005, 2006
- 2.4L Dodge Caravan: 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
- 2.4L Dodge Grand Caravan: 1996, 1997
- 2.4L Dodge Stratus: 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
- 2.4L Plymouth Breeze: 1997, 1998, 1999, 2000
- 2.4L Plymouth Grand Voyager: 1996, 1997
- 2.4L Plymouth Voyager: 1996, 1997, 1998, 1999, 2000, 2001
Symptoms Of Low Or No Engine Cylinder Compression
I've noticed over the years that I've been working as an automotive repair technician that compression problems usually fall into one of two types of categories.
In the first type, the compression problem causes the engine to crank but not start usually because all four cylinders have 0 PSI compression.
The majority of these no-start cases were usually due to a broken timing belt. In a few other cases this was caused by a blown head gasket.
In the other type of compression problem, the engine runs but runs with a rough idle or a misfire problem.
In these cases you're going to see one or more of the following symptoms:
- P0300: Random Cylinder Misfire.
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
Besides a cylinder misfire condition (or a rough idle condition), your 2.4L equipped Chrysler (Dodge or Plymouth) vehicle is going to suffer from bad gas mileage. You're also going to notice a heavier exhaust smell coming out of its tailpipe. Also, since the engine is not running optimally, it's not going to be as peppy as it was once.
Important Tips And Suggestions
TIP 1: Do not remove the spark plugs from a hot engine. Removing the spark plugs from a hot engine can result in damage to the spark plug hole threads.
If the engine has been running for any length of time let it cool down completely before removing the spark plugs.
One method that I have used to cool the engine down in a matter of 15-20 minutes is placing a box fan on top of it to cool it down.
TIP 2: The engine has to be cranked to test the compression, for this reason take all necessary safety precautions while working around the engine when it's being cranked.
TIP 3: Have your helper wait outside of the vehicle till you're done setting up the test. This way you'll avoid having your helper accidentally crank the engine while you're installing the compression tester.
Which Compression Tester Should I Buy?
There are lot of engine compression testers to choose from and many places to buy them. I'm gonna' make two recommendations to you:
1) Which one to buy: The engine compression tester that I have always used is the Actron CP7827 Compression Tester Kit. My only complaint about this engine compression tester is that it does not come with a case to store it in.
TEST 1: Finding The Dead Cylinders
You've probably already noticed that the spark plugs sit right on top of the cylinder head on the 2.4L engine in your Chrysler (Dodge or Plymouth) vehicle.
It's very common to find that the valve cover gasket is leaking engine oil into the spark plug tubes.
If you find, when removing the spark plugs, that they are covered or swimming in oil then you have probably found the cause of the misfire problem you're trying to troubleshoot (if you're troubleshooting a misfire problem or rough idle problem).
If you do find the spark plugs covered or swimming in engine oil I still recommend that you follow through and check engine compression.
If you don't have a compression tester, you can borrow one from your local auto parts store or you can buy one Online. Check out my recommendations here: Which Compression Tester Should I Buy?
IMPORTANT: Do not remove the spark plugs from a hot engine or you run the risk of stripping the threads of the spark plug holes in the cylinder heads. If the engine has been running for any length of time, let it cool down completely before removing them.
OK, these are the test steps:
- 1
Disable the ignition system by disconnecting the ignition coil pack from its electrical connector. This will prevent the ignition coil from sparking during the test.
- 2
Remove the spark plugs. Remember, the engine can not be hot!
When removing the spark plugs, be careful not to drop any of them on the floor, or you run the risk of having the spark plug's porcelain insulator crack and then you'll have a misfire on your hands. - 3
Thread the engine compression gauge into the spark plug hole for the number 1 engine cylinder. Hand tighten the compression gauge only! Do not use any type of tool to get it tight.
- 4
Have your helper crank the engine till the needle on the compression gauge stops climbing.
- 5
Record on paper the value at which the needle stopped and the number of the engine cylinder on a piece of paper. Release the pressure on the gauge and repeat this step one more time.
- 6
Repeat steps 3 through 5 on the remaining cylinders.
Let's examine your test results:
CASE 1: All four cylinders had 0 PSI. This test result tells you that the engine has an internal mechanical problem.
The most common cause of this condition is a broken timing belt.
Your next steps should be to check the condition of the timing belt. I would also recommend that you check for a blown head gasket.
CASE 2: One or more cylinders had a low compression value compared to the others. This could be normal or it could be causing a problem.
To find out the next step is do some math and see if the low compression value is lower by more than 15% of the highest compression value you got. To find a detailed explanation of this calculation go to: Interpreting The Compression Test Results.
CASE 3: All four compression values were similar and above 120 PSI. This lets you know that a compression problem is not behind the no-start or misfire problem you're trying to troubleshoot.
