DT 466E Engine No Start Low Oil Pressure
This problem started during the morning start up…. the bus was 30 minutes out of town it was plugged in but it would not start. The bus in question was a 1998 International conventional with a DT 466E diesel engine. It was the middle of winter so the cold temperature was a contributing factor with the no start situation.
We went out to have a look and could not get it going so the next step was to tow it in and have a closer look. We determined it was the engine oil pressure pump not getting enough flow to the high pressure oil pump that feeds the HEUI (hydraulically actuated electronic unit injector) system.
The oil pump is crank driven and has a direct passage to the high pressure oil pump reservoir. There is no filter in between so filling this reservoir does not take long during cold starts or after oil changes. Just think of the extra cranking it would take to get the engine started if this oil had to go through a filter?
So once we got the hood, radiator and charge air cooler out of the way we were able to access the front cover and drive gears. The oil pump itself is bullet proof since it’s driven directly off the crankshaft. The one thing we did notice was the oil pressure regulator had scoring on the piston.
This was the only really obvious problem that could effect the engine oil pressure. The high pressure oil pump runs at very high levels (thousands of PSI) so it would falter if it did not receive enough oil flow especially for an early morning starting attempt on a cold morning.
This job obviously was a lot of work so we decided to replace the oil pump based on the mileage of the bus which was around 384,000 km. To go through all this work without covering all the bases related to the low oil pressure problem might come back on us in the future.
With the oil pressure pump and regulator replaced we also started using 0W40 engine oil to provide lower viscosity providing easier flow through the oil galleries. This was an extra step just to increase our chances of a successful start up every morning.
Since this repair the bus has been working very well. The high mileage on this DT engine was a factor and we changed the HEUI o-rings as well since that also directly effects starting. The o-rings separate the oil from the fuel around the injector and if one of them fails this will also cause poor starting among other problems.
If the injection control pressure is low it may be the injector o-rings, a defect in the injector itself (poppet valve) or worn out pump. The symptoms of a low oil pressure to the injectors will be low power especially when hot, high fuel and oil consumption and blue exhaust smoke especially on start up.
This repair involved checking oil pressures on the engine side and the high pressure side and helped us determine what was causing the problem. This was the first place to start for us and since the engine would not run it made us make a decision to start from the source of the oil flow which was the engine oil pump system.