Had a very weird thing happen last Friday. I started pulling up a hill that I've done a 100 times before, and it seems like the engine is lacking power. The torque just wasn't there. I actually had to drop down another gear from what I usually pull that hill in. I looked down at the gauges and my oil and coolant temps were both running just under 250 C! My oil pressure was down to around 10 psi! Funny thing is, there are NO warning lights or buzzers going off. At this point, I'm just cresting the top of the hill and was able to find a bit of a pull-out there.

I get her off the road and shut her down. Thinking I'm going to find a God-awful mess when I open the hood. I open it up, and the water and oil levels are good, coolant is still green, oil is still black, no bubbles or foam. No discernable leaks either. Belts are still in place and tight. The fan was running during the entire pull up the hill. I call the boss, fill him in, and he suggests it's just a computer problem. Tells me to start it up again and see what it does. I fire it up again and the oil and coolant temps are back to normal. ??? Boss tells me to carry on and just keep an eye on everything.

Carry on I did, and I knew I had another big hill to climb just before my consignee. Same thing happens again. Only difference this time was the oil pressure stayed around 20-25 psi. I didn't shut it down this time, just carried on. Made it to my destination, shut it off for a bit, and the temps were normal again after the restart. Ran cool all the way home as I was empty.

I had an auto greaser line that was leaking on my right steer wheel. The shop pressure washed everything on that side of the engine, including the block, before I left. I wonder if something was affected by the water? Engine is a Cummins ISX.

Nurse it for a while, it will show you if there's other problems.