Oil cooled piston
- No risk of contamination.
- No extra pump or pipes required.
- Costly, excess oil required.
- Low specific heat capacity.
- Low temp difference with piston crown.
- Carbon deposits at high temperature.
- Oil oxidized at high temperature.
- No hardness scale formation.
Water cooled piston
- Chance of water contamination in oil.
- Extra pump and pipes required.
- No cost for water.
- High specific heat capacity.
- High temperature gradient with crown.
- No chance of deposits if cooling water is treated.
- Can operate at high temperature.
- May form hardness scale.