Fluctuating Oil Pressure

[CumminsPuller]

Just got a call from my brother-in-law. He drives his 96' CTD, 3500, auto, 3. 54, 92000 miles, gauges, TST #8, for his job. He pulls a 40' double axle goos-neck tralier. The other day while only carrying 1500lbs on his tralier his oil pressure dropped, then came back up... ..... He just called me now and said his oil pressure was fluctuating again..... Right now he is loaded GVW including trailer and load at about 30,000lbs. At 60mph, on the interstate, flat driving, overdrive off, 2300 rpms, his pressure just dropped to 18 then slowly worked its way back up, he then took his foot off the throttle, and it dropped then started coming back up, then back on the throttle and it dropped again then stabilized at 35 to 40 psi. Any ideas what is going on or what I can have him check, anything..... thanks for the help.....

 

[illflem]

10 to 1 it's just his sender or the wiring to it, easy fix and not too expendsive.

 

[Dreher]

I'll second illflem. I fixed the same problem on my 96 with a 20. 00 sender from the local parts store.



Bob

 

[ScooterH]

oil filter

I have had oil filers cause oil readings like you're describing

 

[Missouri Mule]

Sounds like the sender or connector/wiring.



Could have some dirt plugging the pickup tube and it freeing itself, or oil pump going.



Can the by- pass valve stick open?

 

[DLysne]

Where is the sender located and how does a guy check to see if it is working properly?

 

[Missouri Mule]

DLysne,

Oil sending unit is located on driver's side of engine. It is a few inches to the rear of the vacuum and power steering pump. Look through wheel well should be able to see it.

Test with multimeter on ohmms setting. If the reading jumps around the sending unit is bad.

Make sure is clean and tight. Also check the pins in the connector for being loose or bent.

good luck