I have a 1993 pete with 3406c model mechanical on it's second overhaul has 550.000 miles. the oilpump gear went out i replaced the gear and pump with cat reman 138.000 miles back. my problem is my oil pressure was 58-60 at 180 temp. was fine when i parked it. sat six days next time i started it wouldn't go over 50 pounds psi cold i ran down to our yard shut it off checked oil didn't seem deluted on my fingers was half gallon low i added one lucas oil stableizer. didn't change it runs 45 pounds cold at 1000 rpm 50 at 1900.
Engine: 3406C MECHANIAL
Hi my name is XXX. X will try to help. First try connecting a manual gauge to verify accuracy. It sounds like it is time to roll a sett of rods and mains in it. You will gain back your lost oil pressure and by some time until your next overhaul. Your rod and main bearing clearances have a great affect on your oil pressure. I hope this helps. Thanks for using JA
1995 Wyo-tech graduate 17+years shop/field experience/on all major brands of heavy equipment and trucks.