Recently dismissed a driver and just drove the truck he turned in today. It carries 65 psi oil pressure hot while moving or fast idle. When rpm drops to idle, the oil pressure drops to around 20 and the gage flutters quite a bit. Found a fuel ticket from his last fuel stop, he bought 4 gallons of oil, so it may have been run low. Pulled an oil sample, took it to Speedco for analysis and everything is perfect with 20k mi. on the oil. It seems to me that this truck used to carry 40 psi at hot idle, my B Model does in the W-9. Anyone here think I may have oil pump problems or is this where the E Model runs? I just can't remember, I've not driven this particular truck in 3 years.

 

My '97 3406E runs about 50 psi hot and at road speed under load and will idle about 20~25 hot. I've wondered if this was OK too but it runs fine and uses only about 1/2 gal of oil toward the end of a oil change cycle ( 12000 ) Mine has 1,313,000 miles with 263,000 since a total in frame.

 

My 3406E runs 70 hot and 45 idle, they all will vary some.

 

yeah, i guess it's the fluttering of the gage that worries me. I don't want to send it to NYC or something and find out I have a bad oil pump. Guess I'll just pull it and replace it just to make myself feel better.

 

Replaced the oil pump, found it had been scored pretty badly. Rod and Main bearings look like they just came out of the box. Liners look perfect from underneath. Got lucky on this one!!!

 

what kind os psi's does she run now?

 

65 cold. 65 at operating temp fast idle or operating rpm and 38 at hot idle. This is with a brand new Cat oil pump. Also found debris in the relief valve of the old oil pump, that probably caused the low psi and fluttering of the gauge before.