What causes sticking piston rings? And do diesel engines suffer from it?

[emmett442]

low tension/low friction rings that don't ride the cylinder wall crosshatch enough to keep them rotating. As long as they rotate, there's no buildup in the grooves they don't stick.

 

[KrisZ]

Diesel engines also suffer from the rings sticking and burn oil. But since diesel engines are such a minuscule portion of all vehicles, you naturally won’t hear a lot about them.

 

[CarlB]

Sticking from deposits is one option. Another is bent ringlands causing a stuck ring.

 

[oil pan 4]

I have seen stuck rings on neglected lawn mowers from dirt and lack of oil changes.

 

[Jetronic]

Why would they have no fuel mixed in between the piston and cylinder?

during compression, it's pure air that gets compressed and would blow by the rings. The fuel is injected very late, when it's supposed to burn, and into a bowl in the head (indirect injection) or in the piston (direct injection). fuel burns as it's being injected, there's very little chance to reach the cylinder walls unless on a stone cold engine, or one with low compression.