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So I foolishly let a Ford dealer change the oil in my 1993 F250 7.5L. They put 10 quarts of oil in. I drove about 20 miles to a Home Depot and noticed that oil pressure was WAY below the N(ORMAL). I pulled the dipstick and oil level was beyond the top. I drove the 20 miles back to the dealer and had them redo the oil change with 6 quarts, as well as adding a notation in the service doc stating that they put in 10 quarts of oil.
I drove 250 miles home, oil pressure got a bit better, however the gauge reads almost one letter lower on the NORMAL gauge than it used to. Pressure used to be on the left edge of the O and has been there for 50,000 miles. Now it reads just barely into the N.
What should I look for, and what should I be asking the dealer?
PS. I need to drive way into rural Mexico to pick up a 4 ton load of stone, an 11k load counting trailer. Any worries for me? I wouldn't want to have a breakdown on that trip.
Did you replace the oil pressure switch with an oil pressure sending unit? Your generation truck came from the factory with a oil pressure switch that moves the oil pressure gauge needle to the middle of the range. Unless you (or the previous owner) modified it, the only thing your oil pressure gauge tells you is that you have over 7 psi of oil pressure.
As these trucks age and the wiring and switch contacts wear, the oil pressure gauge dips down lower and lower due to the normal increase in resistance in the wiring/switch.
Like was said above, the gauge is just a yes or a no for pressure, not a real PSI reading. You could install a real gauge and verify but I doubt you'll have any issues.
It's possible that they touched the wire that clips on to the pressure switch and that is what changed how your gauge is reading out.
