I am trying to do this on my phone so please excuse any typo's.
Short story - drove from Indianapolis to Chicago without issue. Left convention center to go back to hotel and noticed oil pressure fluctuating from 40 to 0 and back at highway speed. Jumped off toll road in a bad area and quickly put 2 quarts in because the change oil light came on a couple of weeks ago and I figured that was the issue. Also, I wanted to hurry and get to the hotel. Oil pressure still fluctuating - Oops probably too much oil now. Pressure dropped to 0 most of the way back - 10 miles. Temperature never moved so I kept going. Got to hotel and it kinda sounds like a diesel. Is that from too much oil? Any ideas? I read that sending unit could be the culprit. No tools with me but AutoZone will probably let me use some if I get the unit there.
Thanks for any advice.
Chuck

 

Did you bother to check the oil using the dip stick? Aside from that, when the oil pressure dropped to 0 why did you keep driving? Does the engine even turn over now?

 

* this should be at the end, but I can't scroll down the window on my phone... The truck runs fine this morning. I'm going to get the oil changed and the try the sending unit. Hopefully I can salvage our trip and the truck is ok.

Yes, I checked the oil on the dipstick. It was very dark and hard to see. I put in one quart and tried to get back on the toll road. The pressure continued to fluctuate. I pulled over in a very rough part of town, quickly poured in another quart and got out of the asap. My wife was in the car. I kept driving with the 0 reading because I really had no other choice. The truck was running just fine and the temperature never rose.
Thanks for the help.

 

My oil pressure started fluctuating one day and I replaced the OP sensor and back to normal but mine never went to 0 though.

 

yeah those are common, if you had no oil pressure your engine would have been knocking almost instantly. i used to own a blazer that had 30psi upon cold start and would go down to zero slowly over the course of 20 minutes so i always drove it at 0 oil pressure for years, never cared about the gauge

 

[QUOTE Got to hotel and it kinda sounds like a diesel. Is that from too much oil? [/QUOTE]

This part of his first post kinnda bothers me. No I wouldn't think too much oil would cause a diesel sounding rattle, inless maybe its way over full and the crank it wiping it into a foam, not good for the motor tho in any terms - Makes me wonder if the oil pump isn't on its way out also.