I have a 2003 Expedition 5.4L v8. It has 104K miles on the original engine. We were heading to my daughter's basketball tournament yesterday and the oil pressure gauge drop to bottom and the "Hi Temp No Oil Pressure" came on. It flickered on an off with the pressure gauge going back to normal and then back down. I stopped almost immediately, luckily in a town with a gas station. I added a quart of oil to be safe. It was topped off after that quart.

We let it sit for about 15 minutes and then started it again. The pressure gauge went back to normal and no warning light was on. We started off again and within a couple of miles it did the same thing. However, this time the pressure gauge didn't come back up. It stayed pegged at the bottom. We pulled over immediately and called for assistance. I had it towed to the repair shop.

I am thinking it may be the oil pump that went out. Anyone else have suggestions? Honestly, I hope it is only the oil pump that is a relatively easy fix.

Thanks for any input.

 

I'd ask the shop to plumb in a mechanical test gauge. My guess is the sendor is at fault. The sensor is a simple mass produced switch and they do fail. Did the engine make any ticking noises as the gauge dropped? The valve "lifters" would allow valve lash as soon as they loose oil and start ticking.

 

The pressure sensing switches on these things ...are well known for failure and causing panic.

Replace the sender switch.

 

Absolutely the pressure switch. Same thing happened to me. Cheap fix but it wasn't easy to get too. Mine was next to the oil filter and it was tight for my hands.

 

My mechanic replaced the pressure sensor and that had seemed to clear things up since the original incident back in January.

This last week, the same thing happened again. Luckily we were just a couple of miles home and I was able to idle my way back home. It was time for an oil change, so I did that. After changing the oil, I took it for a test drive and to get the oil running through the system and see if the problem persisted. The car was fine until was finishing with the basic test and was coming to a stop. The pressure dropped and then would come back up. It did this another 4 times as I slowly headed the last mile home.

Any ideas on what else might be causing problems?

 

bad wire going to the switch, or could be a loose connection at the switch.

 

Sounds like the switch is bad again. Put an oil pressure gauge on there and verify your oil pressure. If it is good, replace the switch. If it is bad, address the cause.

 

Did the engine get noisy, as in lack of oil noisy, when the pressure dropped off?