Spark plug fouled and engine block problem?

[1998yellowstang]

I pulled the spark plugs yesterday. All of the spark plugs look similar, except for the middle passenger spark plug. There is a heavy build up on it. I’m assuming from burning oil. Also, all the plugs had a bit of oil around the threads of the first ¼ - ½ of the plugs. My friend seems to think that it’s the piston rings.

Also, the inside of the engine block , right below the cylinder heads is a darker color. Does this look like an issue as well?

Any input would be greatly appreciated!

[evildky]

Looks like a bit of head gasket seepage. Before dismantling the engine you could have run a compression test. Any cylinder that tested low you could add a squirt of new motor oil to and retest, if the compression raises it's a ring problem is not it's the HG or valves. You can still do a leakdown test, most parts stores should have the tool for load, you pressurize the cylinder then listen to see if the air is leaking out the intake, exhaust or the crank case.