I always wondered how this engine was holding up to what I was subjecting it to, and decided that if I was going to have the plugs out for replacement anyway I might as well do a compression test. Technically, the plugs are not due for replacement until 105,000 miles. But I also decided that if I was going to check the condition of the engine it should be done just before the warranty expires, not just after.
You will need:
1) Compression tester. These can be rented at any auto parts store.
2) Ratchet.
3) 10mm socket.
4) Spark plug socket (the smaller one of the two).
5) 6" ratchet extension
6) Replacement spark plugs. I went with the Denso IKH16TT.
7) Silicone dielectric grease.
8) That's it!
The compression test should be done with the engine HOT OR WARM, since this is it's normal operating condition. So warm the car up.
The first thing you will remove is the baffle on the side of the air cleaner housing. There is one 10mm bolt that holds it on, and you should be able to wiggle it out of the side of the housing by pulling it to the left.
The next thing you will remove is the air cleaner housing. There is one bolt on the left side..
...and one on the back.
The air cleaner housing can be separated and the filter removed. The rear section of the housing is secured on the bottom to the top of the valve cover by a rubber grommet. Wiggle it up and out.
The PCV hose is clipped onto the right side of the air cleaner housing. Simply pull it free.
The intake hose can be removed with the 10mm socket by loosening the lower clamp. Pull it free.
There is one electrical connector to disconnect at the housing for the Intake Air Temp Sensor...
The front of the air filter housing can be swiveled out of the way and rested on the battery, or you can disconnect the PCV hose with pliers and remove it completely. The coil packs should now be visible. Each is retained with one 10mm bolt, painted orange.
Remove the coils by removing the bolts and disconnecting each of them. Wiggle them up and out. I would keep them in the order they were removed so they can be reinstalled on the cylinder they came off of.
Removing the spark plugs is pretty self-explanatory. Just unscrew them. If you are planning to replace them they can be discarded. If you are going to reinstall them, keep them in order so you can put them back into the appropriate cylinder.
Once all have been removed, disconnect each fuel injector connector at the fuel rail. This will keep the PCM from fueling the cylinder, as excessive fuel in the cylinders during the test will wash the cylinder walls and affect the readings.
Okay, you are ready to start the test! Screw the tester securely into the #1 spark plug hole. Get into the car, FLOOR THE ACCELERATOR, and crank the engine over about ten times. You need to floor the accelerator to allow the throttle body to open wide and allow as much air to enter as the cylinder needs.
You should get a reading like this on the tester...
...and #2...
...and #3.
And there you have it! On my motor the results are read as:
Factory specs are 205 psi for a new motor. The readings here indicate that at the end of my powertrain warranty this is still a healthy motor! This engine got no Superman maintenance...just by the book. Mobil 1 0w-20 AFE full synthetic every 7,500 miles...religiously. Plugs looked like you would expect 100,000 mile plugs to look.
Reassembly is the reverse of disassembly. My coils were sticky coming off, so I put some dielectric grease in the ends when reinstalling them.
When I started the car after reassembly, the check engine light was on. It gave me a code P0113, which is for the disconnected IAT sensor. I am not sure if this code will self-resolve over time, but I just reset mine with an OBDII reader. Any auto parts store will reset the code for free.
And there you have it. Please post up your readings if you do a compression test. Let's see how tough these little three-holers are.
"Scarlett and Marsha"
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