So I spent some time on the truck today. I have the new water pump and thermostat but I have not changed them yet as I couldn't find any leaks by the water pump, pulleys or anywhere on the truck. I even removed the shroud to check the radiator too. The radiator was replaced last year but I wanted to double check.
I proceeded to remove the spark plugs to check them and look inside the cylinders with a small camera. These plugs have been for about 35k miles. I noticed on cylinder #6 that the ceramic was whiter than expected or at least compared to the others. The piston also has some white spotting on it too. All of the other plugs are darker in comparison. Cylinder #4 piston had some white spotting but to a lesser degree. All of the other pistons (5, 3, 1 and 2) looked to be mostly carbon colored. I also noticed oil on spark plug #6 too. #2 had some as well so I am guessing there is a valve cover gasket issue also.
I also tried to use a combustion leak tester on the radiator but it never changed color to yellow.
I have attached the pictures below. I also included a picture of spark plug #6 when I changed the previous plugs at 258k miles. Those plugs were on the truck for at least 52k miles as they were on there when I bought it. You can see the plug looked different then.
Thoughts? Head gasket issue?
Spark plug #6
Spark plug #4
Spak plug #2
Piston #6
Piston #4
Piston #2
Spark plug hole #6
Spark plug hole #4
Spark plug #6 from last charge at 258k miles