In this article we look at the topic of oil temperature and oil pressure and explain why it makes sense to monitor these parameters. For this purpose, we prepared our DUCATI DesertX and DUCATI Monster 1100 EVO, using them to show the installation of our CUMPAN Cockpit Assistant, which allows these parameters to be monitored.
Why monitor these values?
First, a short technical overview of why it is useful to keep an eye on oil temperature and oil pressure. On most motorcycles, the coolant temperature is measured as standard and taken into account by the engine control unit – especially during cold starts. Some vehicles also display the coolant temperature. However, engine oil warms up more slowly than coolant, meaning optimal lubrication is usually reached later than the coolant temperature might suggest. Once the oil has reached operating temperature, the engine block is generally warm enough and the uneven expansion of individual engine components during warm-up has evened out. Logically, the engine should only be fully loaded from this point onwards.
Oil temperature and oil viscosity
Furthermore, oil viscosity changes with temperature. In a test on our DesertX, we measured the following values at idle:
At an oil temperature of 23 °C we measured an oil pressure of 7 bar, at 60 °C it was 2.7 bar, and at 95 °C only 1.6 bar.
When oil temperature is low and the oil is viscous, the oil pump has to build up higher pressure to circulate the oil. Conversely, high oil temperatures can cause the oil film to break down because the oil becomes too thin. Temperatures above 130 °C should therefore generally be avoided.
Oil pressure
When talking about viscosity, we also have to look at oil pressure, as it is directly related to oil temperature. With cold oil, very high pressures can occur – in some motorcycles well over 10 bar. With hot oil and low engine speed, oil pressure can drop below 1 bar. Since the oil pump is driven by the engine, its delivery rate depends directly on engine speed. At higher rpm, more oil is delivered and oil pressure increases. Monitoring oil pressure can therefore provide many important indications:
If oil pressure is very high, the engine is (still) cold – for example in winter – and should not be heavily loaded.
- If oil pressure is unusually high even with a warm engine, an oil line may be partially blocked, restricting oil flow.
If oil pressure is very low, there may be several reasons:
- The oil may be too hot and the pump cannot build sufficient pressure
- The oil may be aged and diluted with fuel over time, making an early oil change necessary
- A mechanical problem may be present. If oil pressure suddenly drops significantly compared to normal, the motorcycle should not be ridden further, as a defect or leak in the lubrication system may cause serious engine damage
- Oil pressure may also drop completely or fluctuate. A low oil level can be the cause, as the pump then draws in air and can no longer supply oil evenly. In this case, the oil level must be checked immediately and oil topped up if necessary
This is a brief overview of the different scenarios that can occur in connection with oil temperature and oil pressure. Depending on the vehicle, usage and operating conditions, monitoring oil pressure can be very useful. Oil temperature should always be taken into account, if only to warm up the engine properly and protect its components from unnecessary wear. For this purpose, our CUMPAN also features an integrated shift light that provides visual feedback when a configurable threshold for engine speed and engine temperature is reached, indicating that engine speed should not be increased further. We usually set this threshold to 60 °C, as in our experience the oil is already sufficiently fluid at this point and provides very good lubrication.
