I recently purchased a used Ford F150, V6, 4.2 liter, 137K miles. While driving it today, the oil pressure dropped to zero and the oil pressure light came on. I checked the oil level and everything was fine. Since I really didn’t feel like having it towed home and being I didn’t pay much for this vehicle, I decided to drive it home - about 40 miles on and off the highway. The oil pressure gauge would sometimes “bump” up and the light go off and come on again. The engine temperature never rose at all and the truck ran fine. My question is, does this sound like a bad oil sending unit ?? I had an F150 years ago in which I had to replace the sending unit but I was under the impression that the oil light doesn’t work off the same sending unit and I felt that this could very well be a real problem - although one would think that driving it that distance would cook the engine. Any ideas ???
On late model Fords, the warning light and the gauge are one in the same. The “gauge” does not actually display oil pressure. It’s just an on or off indicator like the light.
Replace the sender.
On this 1997 Ford F150, there is a seperate oil pressure gauge and a seperate oil (idiot) light. I thought they had seperate sending units for each ??
If this is the stock oil pressure gauge, then the light and ‘gauge’ use the same sending unit. The stock Ford ‘gauge’ is not a real gauge at all. It is either ‘on’ in the middle of the gauge, or ‘off’ at zero. The light uses the same signal to be on and off. You’ll need a mechanical gauge to determine if the oil pressure is at specifications.
Thanks for the info. At this point I may just go ahead and replace the sending unit. I have trouble believing that the truck would run with little to no oil pressure for as long as it did. Isn’t this (the oil sending units) a common problem for Fords ??
If the lifters didn’t start ticking louding, I agree with you. And sending units can go bad in any car or truck. And, this truck is 13 years old. I had a coolant temp gauge go bad after 10 years in my Toyota. It happens.