Oil Leaks on the Cub Cadet RZT50

Gasket Leak

• The pistons in the Kohler engine have gaskets between the piston rod and the piston head. These gaskets prevent air pressure from leaking out of the cylinder, thus reducing compression for combustion. Oil flows over the piston heads to provide cooling during operation. If the gasket becomes worn, oil can seep into the combustion chamber area and leak to the exhaust. Extreme heat or air pressure can cause the gasket to blow completely. A gasket leak is sometimes indicated by white smoke.

Breathers

• The SV830 engine’s breather system controls how much oil is in the piston head area during operation. When the piston compresses downward, a vacuum is created. The breather reed opens when the piston pushes down, allowing air to pass through the breather hose. When the piston pushes up, the reed closes and passes oil through a mesh filter and back to the crankcase. If the breather reed is broken, oil will instead pass into the air system and leak into the combustion chamber.

Oil Contamination

• Oil contamination can cause an oil leak in the RZT50 if it’s excessive. Contamination reduces the cooling properties of oil. Excessive heat can cause gaskets and seals in the lubrication and cooling system to blow. Conventional oil contains natural contaminants that can break down the lubrication system over time. Oil has to be changed regularly according to the maintenance schedule to prevent the breakdown. Ventilation systems and debris screens must be kept clear so that cooling air can enter the engine without contamination.

Fastener Torque

• Parts like the breather tube and its accessories make use of gaskets and O-rings to seal the lubrication and ventilation systems in your RZT50 engine. Fasteners must be properly torqued onto these items to ensure a good seal. Torquing them too tight can cause them to rip, while a torquing them too loose doesn’t provide a sufficient seal. Follow the service manual’s torquing specifications to keep oil from leaking during operation.