Oil Pressure Question

[gear jammer 91"]

I recently towed a trailer a couple thousand miles and noticed that while towing my engine temp would come up close to the second line on the gauge and once it sat there a while the oil pressure would drop off below the first line on the gauge. I just switched from delo to rotela, I towed the same trailer a couple time with my truck before but it was cooler outside and the engine temp did not get up as high and a I was runnin delo. Both oils are 15-40. Has anybody else had or heard of oil pressure droppin below normal cause the engine was runnin hotter? I was doin about 65 down the free way and goin faster did not help, the oil level was in the safe range on the dipstick. Once the truck was runnin normal temp the oil pressure gauge read normal?

[mprmn08]

i cant give any personal experience from that but it would make sense cause the oil would thin out when running hotter. as long as it didnt fall super low i wouldnt worry about it.

[dpuckett]

Verify your oil pressure with a mechanical gauge. These trucks are notorious for having bad sending units.

DP

[Philip]

Oil pressure sending unit is bad most likely.

That kind of wakes you up to scan the gages and see oil pressure at 0 PSI.

[gear jammer 91"]

I think it was showing around 3psi at 70mph. (no tach so I don't know how many rpm that is.) I think I'm gonna mount a mechanical gauge in the cab permanently as soon as I figure out a good spot.