I was wondering about what are the normal oil pressure readings for the 8.3?
at 2100 rpm I am running 31-32 psi but at idle it looks to be getting pretty low about about 12psi.
at operating temp (around 180 /190*) and 1800 rpm, ours is usually about 50 psi and drops to 20 at idle.
That is more in line what I thought as that is about midway on the gauge.
Thanks
I'll go with the 12 to 15 at idle and 50 at operating temp which is 180 and rarely over that. Pulling the hill out of Laughlin Nevada ( which is about like the Siskiyou Mtn pass) she stayed right at 180/185 at mid day. I was so proud of the her.
it was running about the 180° mark, i was north of Austin, Tx in some rolling hills and the old girl was rolling along just fine. I dont remember it being this low before and the oil is down to about the 3 quart level on the dipstick and does not get out of the checked area until 4 quarts low.
I was wondering if it needs a new oil pumps.
Sorry..gonna crash the party..with a CAT...42psi @ 1400...23 psi @ idle hot..
That is closer to mine but mine is a Cummins, my reading was after about 150 miles.
Many dipsticks on these coaches need calibrated, add a quart and see if it helps. Too many threads on this subject. Air entrainment in the oil can lead to abnormal pressure. Sorry I missed you when you were in town
I will look up what the PO was using and go get some and try adding 1 qt at a time and see what it does.
That is OK, I will be back I think in April unless I am still working in FL "LOL"
Ours (Cummins 8.3 1993) runs at 90 psi while driving and at idle can drop momentarily to about 60. As the time since the last filter change increases the max oil pressure seems to decrease. This gradual decreasing has just happened to us and since our recent oil and filter change, the psi is back up to max when driving.
That seems incorrect. Bad gauge or sender
Mine runs about 12 PSI at idle and 52 PSI at 1800 RPM with 180 degree water temp.
Those reading are HIGH. Likely sender unit or gauge issue.
Speaking of oil pressure senders, does the (VDO)gauge and the dash warning light get information from same sender? This is a 1992 C8.3 Cummins.
Thanks for your reply.
jk
On our '93 U280, looking at 12V Wiring Diagram B-2037, the answer is "Yes". Gauge and light signals are supplied by one sender labeled:
SENDER ENGINE OIL PRESS
LOW OIL PRESSURE SWITCH
Readings from sensors are notoriously for false readings. A new sender and checking grounds is a good thing as some readings change with the headlight off or on.
A mechanical gauge back at the engine is a good yardstick to use. With the engine warm, I would expect 15 to 20 psi at 600 RPM idle and somewhere around 50 at cruising RPM.
Oil pressure at idle is another good reason to avoid idling the engine for prolonged periods.
Pierce
Sometimes turning a sender in a bit will restore a corroded ground, if present, from it to the engine.
I'm not trying to be captain obvious, but if you had a true oil pressure problem, the engine would've blown up by now.
Oil pressure readings are notorious for being precise, but not accurate. I work on many engines, and I just try to view the data qualitatively.
A) Does pressure gauge read zero when engine is off
B) Does pressure gauge rise when starting engine?
C) Does gauge rise when RPM increases?
D) Does pressure go down slightly as oil warms up?
If all those are yes, then most likely all is well mechanically, and you have an instrumentation/calibration issue.
You Krushed it!! ^.^d :))