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Topic: C8.3 Oil Pressure Readings (Read 1539 times) previous topic - next topic

C8.3 Oil Pressure Readings

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.
Steve

1997 U270 36' build 5179
Motorcade #18147
1980 CJ5

Re: C8.3 Oil Pressure Readings

Reply #1 –
at operating temp (around 180 /190*) and 1800 rpm, ours is usually about 50 psi and drops to 20 at idle.

Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: C8.3 Oil Pressure Readings

Reply #2 –
Quote from: FourTravelers –
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
Steve

1997 U270 36' build 5179
Motorcade #18147
1980 CJ5

Re: C8.3 Oil Pressure Readings

Reply #3 –
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.
Robert and Susan
 1995 36' 280 WTBI 8.3 3060r
 1200 watts on the roof, 720 Ah of lithium's
 Build # 4637. Motorcade # 17599
        FMCA  # 451505
        18  Wrangler JLUR

Re: C8.3 Oil Pressure Readings

Reply #4 –
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.
Steve

1997 U270 36' build 5179
Motorcade #18147
1980 CJ5

Re: C8.3 Oil Pressure Readings

Reply #5 –
Sorry..gonna crash the party..with a CAT...42psi @ 1400...23 psi @ idle hot..
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)

Re: C8.3 Oil Pressure Readings

Reply #6 –
Quote from: Hans&Marjet –
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.
Steve

1997 U270 36' build 5179
Motorcade #18147
1980 CJ5

Re: C8.3 Oil Pressure Readings

Reply #7 –
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
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: C8.3 Oil Pressure Readings

Reply #8 –
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"
Steve

1997 U270 36' build 5179
Motorcade #18147
1980 CJ5

Re: C8.3 Oil Pressure Readings

Reply #9 –
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.
Woody & Sandy Lloyd
1993 Grand Villa
Unihome U280
Cummins / Allison
Build # 4379

Re: C8.3 Oil Pressure Readings

Reply #10 –
That seems incorrect.  Bad gauge or sender
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: C8.3 Oil Pressure Readings

Reply #11 –
Mine runs about 12 PSI at idle and 52 PSI at 1800 RPM with 180 degree water temp.
Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW

Re: C8.3 Oil Pressure Readings

Reply #12 –
Quote from: Mike_Sandra_Lloyd –
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.

Those reading are HIGH.  Likely sender unit or gauge issue.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: C8.3 Oil Pressure Readings

Reply #13 –
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
Jack and Cathy
1992 U280 Unihome 36' Build #4034
Cummins 8.3 /  Allison MT647/ PacBrake
Apopka, FL / Barre Center, NY

Re: C8.3 Oil Pressure Readings

Reply #14 –
Quote from: kimosabe99 –
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.
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
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: C8.3 Oil Pressure Readings

Reply #15 –
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
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: C8.3 Oil Pressure Readings

Reply #16 –
Sometimes turning a sender in a bit will restore a corroded ground, if present,  from it to the engine. 
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: C8.3 Oil Pressure Readings

Reply #17 –
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.
1998 U270 34'
 

Re: C8.3 Oil Pressure Readings

Reply #18 –
Quote from: krush –
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  :))