I have problems with my 2004 Honda Civic. My engine overheats and there is no hot air coming to the cabin, even if the temperature gauge shows Hot. Every mechanic I know told me that it is a clear sign that the head gasket is blown (they never saw the car - they just guessed after hearing the symptoms from my description), so I started by removing the spark plugs and got an inspection camera inside the combustion chamber. I found some wet spots on the surface of the piston heads:
Piston 1 (Left)
Piston 2 (Middle Left)
Piston 3 (Middle Right)
Piston 4 (Right)
| Piston 1 | Piston 2 | Piston 3 | Piston 4 |
Do those wet spots indicate that there is coolant or oil leaking in? Piston 2 is bone dry, while the rest are slightly wet-ish.
I also looked at the spark plugs:
But they look okay. It could be that it's been only one day since I noticed the overheating. The only thing that can be noticed on the spark plugs is that the one that goes on piston 2 (the dry piston) has some buildup on it and feels rustier. I'm planning to get a leak tester in the following days, but I was wondering if it is possible to actually detect a leak only by visual inspection. And why are three pistons wet and one dry?