The present disclosure relates to a coolant system to cool an engine assembly. The coolant system includes a coolant pump impeller with multiple concentric ribs extending axially on a first side of the coolant pump impeller and multiple vanes extending axially on a second side of the coolant pump impeller. The coolant system also includes a coolant rail to collect coolant from a water jacket that surrounds portions of cylinders and a cylinder head of the engine assembly. The coolant system further includes bleed fittings to remove trapped air as the coolant system circulates coolant through the engine assembly. First and second bleed fittings are provided on opposite corners of the engine assembly such that either the first or the second bleed fitting is at a highest point of the coolant system based on an engine orientation of the engine assembly.

In some embodiments, there is provided a method of controlling a pressure gradient between a combustion chamber and a crankcase of an engine, the method having: receiving, at a control device, a signal indicating that a lubricant container is coupled to a lubricant circulation system associated with the engine, in response to the received signal, providing data to cause operation of a suction control device for facilitating control of the pressure gradient.

A control apparatus is applied to an internal combustion engine. The engine comprises a water pump, and an oil pump. The apparatus makes a second motor to drive the water pump drive the oil pump, if the first motor to drive the oil pump malfunctions. Consequently, if the first motor malfunctions, the oil pump can be driven by the second motor. Thus, the possibility of seizing of the sliding portions of the engine can be reduced. Further, if the first motor malfunctions, the friction in the engine can be reduced, since the oil pump is not driven by the crank shaft.

A chamber fluid removal system including a pump and an ejector is disclosed. The system is arranged in use to pump fluid from a chamber using the pump and deliver it to the ejector as a motive fluid and the system being further arranged to draw fluid from the chamber or from a second chamber as an entrained fluid by entraining it using the ejector and the motive fluid.