papaduck

Something happened at work Monday that told me I need a engine oil pressure guage.

I drive trolleys with Cummins ISB 5.9 engines like in our Dodges. The trolley that I drove was overhauled this winter. When I started it up I thought that the oil pressure was low, around 20 psi at idle. I forgot about it because we have at least one trolley that has a pressure guage that reads at least 10 psi lower than actual. Maintenence had said, "don't worry if the pressure drops to low it will shut the engine down."

An hour later the oil pressure was below 10 psi at idle and between 20 and 25 when pulling at normal rpm's. No tachometer.
2 hours into driveing I noticed a faint smell of diesel fuel. It was just a wiff and passed it off to some spilled fuel when it was filled up that morning. 25 minutes later I smelled it again and passangers said they also smelled it. It was time to get it back to maintenance. Engine was running OK and there was no smoke.

There was no visible fuel leak, there was some oil here and there. The engine was throttled up and oil and diesel came out of the dipstick tube!!!

The crankcase was full of diesel and had thinned the oil causing the low oil pressure. I had not driven this vehicle in at least 3 months so I was not aware of where the oil pressure usually ran.

I will be adding a oil pressure guage soon and will bench mark the normal oil pressures cold at idle, cold at 2000rpm, hot at idle, and hot at 2000rpm. Then if I start getting diesel in the crankcase I should be able tell something is wrong by the change in oil pressure, shut down and check the oil level and possibly save the engine.

The stock guage on our trucks will not give you this information because it is nothing more than a fancy idiot light!

It was found today the CP3 was leaking fuel into the crankcase on the trolley. Hopefully I caught it in time that the engine wasn't damaged.