The viscosity rating is very important for identifying whether an oil is suitable for specific operating conditions: oils with a high viscosity rating are ideal for use in summer, whereas oils with lower viscosity ratings are best in winter. Multi grade oils are capable of adapting and their operating range is described by two numbers: the cold temperature viscosity and the hot temperature viscosity. Leuco S.p.A. recommends using SAE 10W-40 multi grade oils with its pumps.
The code for multi grade oils consists of two numbers separated by a "W": the first number shows the low temperature rating and the second number is the high temperature rating. Multi grade oils help cold starts: their fluidity at low temperatures facilitates cold starts and safeguards the lubricating film even during the critical pump start-up phase.
The maximum hot temperature is 100°C. This temperature was originally chosen to represent the oil temperature and is still used to define SAE ratings. However, developments in engine technology mean that oil temperatures can now reach significantly higher values (150°C or more).
HAWK pumps can use either mineral or synthetic oils!