bubbling in expansion tank

[roger leblanc]

2004 kioti ck30h could it be a head gasket machine has 1200 hours

 

[DonRybak]

That would be my best guess. Could be a crack in the cylinder wall but the head gasket would be my prime guess. Crack in the gasket between the cylinder and water jacket in the block will allow the hot air to be forced into the cooling system on the compression stroke. If the machine was ever over heated it's possible that the head might be slightly warped.

 

[jaxs]

To be certain what you are seeing is combustion gas auto supply stores sell a chemical to put in coolant which turns a certain color in the presence of combustion gases.