Compression Test Results

[Alexia]

152,000 miles, spark plugs replaced at 99,500 miles. Definitely time to replace them. Spark plugs #1 and #2 show abnormal electrode wear compared to the rest. I did a compression test while I was tearing it apart since the engine has been low on power lately. Oil looks fine, the coolant is still clear, but coolant disappears from the overflow bottle from the full to fill level about every two months.

I did two passes through the cylinders and took at least two readings per cylinder on each pass to verify the results. All readings are in pounds per square inch. This is using an Actron gauge and I am unsure of its accuracy.

CYL - PASS #1 - PASS #2
#1 - 167 - 100 - I reinstalled the pressure gauge three times and replaced the o-ring thinking I was going crazy on the second pass then I moved on to cylinder two.
#2 - 138 - 167 - Sudden drop in cylinder #1 followed by a rise in cylinder #2.
#3 - 140 - 140
#4 - 128 /140 - 128/140 - I can hear it miss compressing about 50% of the strokes. I performed several extra readings on this cylinder for verification.
#5 - 140 - 140
#6 - 160 - 160

The sudden change between cylinders #1 and #2 along with the missed compression strokes with cylinder #4 lead me to believe there is a combination of head gasket, valve, or piston ring issues.

Spark Plug Fronts


Spark Plug Backs


Burnt Coil Plug


There is also this lovely noise that started 12,000 miles ago. It is not the flex plate. I inspected that and replaced the torque converter bolts when I replaced the 42RLE at 146,000 miles. The exhaust manifold appears to be fine, but rather hard to tell with it tucked up under the intake manifold.
http://www.youtube.com/watch?v=MMiMhqTydoY

[SilverXJ]

Th #1 plug definitely looks suspect. A torn boot can allow the spark to skip the plug and ground to the head producing a distinct popping noise.