Deutz generator with dangerous oil pressure caused by cold weather
This week we had a stark reminder of the importance of making sure your engine oil is kept at the right temperature.
We’d completed the overhaul of a Deutz driven generator package and prepared the unit for the first test run.
And during that first test run, there was a problem.
As part of the preparations, the oil heaters were left on for 8 hours, but when the engine started, it only registered around 20 Psi pressure, so was shut down within 30 seconds.
The oil pressure would be expected to quickly rise to over 50 Psi, to make sure all critical parts are well lubricated.
This low pressure was a result of two factors:
- The ambient temperature was very low, increasing the viscosity. The heaters helped lower this, but the design meant they needed a lot longer than 8 hours to increase the temperature enough.
- The engine had been modified from an original wet sump, which meant there were additional restrictions for the oil caused by the additional pipework.
These are some of the improvements which would have helped protect the engine running without proper lubrication:
- With the redesign of the sump, the engine would have benefitted from an oil priming pump, which could be operated on a timer. Every 2 hours for 30 minutes should be enough.
- The heaters could be relocated to improve efficiency. Currently, they are located close to the top of the oil level, whereas they would be better placed about 50mm lower, to heat the oil from the bottom up.
- An additional two heaters fitted would counteract the temperature differential in the tank. The heaters cut out at 50°C, yet this temperature is measured locally and is not a good representation of most of the oil in the sump.
The above picture shows the heater location and the changes in temperature in the tank.
Readings were taken after 24 hours of the heaters being on, and the results were 28 °C at the heaters, and 17°C at the oil pickup.
They need 48 hours to get to the right temperature, so the engine could be run with the correct oil pressure.
If you’re having issues with your oil pressure, then it’s well worth considering whether any of these factors are affecting you.