The oil pressure guage is barely above the bottom line, when I stop for a red light, it goes below the min. line, when I take off the red light flashes briefly then goes out. Is this normal?
Assuming your talking about the ISM450 engine. Normal hot pressure will be in the 35 psi area, low idle can drop to about 25 psi, the warning lamp on my Silverleaf shows warning below 25 I think, it shows up when fuly up to temp and at idle.
Reason Cummins lowered the oil psi to the mid thirty area, they claim that is plenty and does not require as much hp at running 50-60 psi.
Maybe someone else will have a much better description for you. I am happy with mine.
Dave M
While the gauge may be off, the red light is definitely not normal.
I scanned back and noticed you'd had what you thought was an overfill after an oil change last month based on the dipstick reading. Did you happen to drain any oil to satisfy the dipstick level? Do you know if the dipstick is calibrated?
Michelle
I have that issue on mine too. The silver leaf shows it comes on at 22 psi. I brought it too Cummins attention and they said there specs show 13 psi as the point they put the warning light. They said that the OEM sets it and it is usually on a stop and start if I put my foot into it that I get the beep. It has been going on for 80K miles and no issues yet.
The manual says the ism450 should take 10 gallons, the place that changed the oil put in 9 gallons in and said it measured full, I didn't check until I drove 250 miles and found the dip stick measured overfill. I'm afraid to add more oil as well as drain oil out. Is a gallon either way going to make that much difference? The oil light coming on and going off briefly has been happening for some time, when I stop.
I was worried when I dropped off my ISC (which ran 40PSI at 60 MPH) and left in my ISM - the ISM runs at 25 PSI at 65 MPH when hot - both Cummins and FOT agreed 25 PSI is correct for my ISM, dash gauge and silverleaf all agree.
Greg, remember to be sure that you have the correct dip stick. Keith Risch told me that some did not, on the model I have (2001). He checked mine, I gather some number on the stick? But I think a few quarts is not critical. There was a very useful thread a couple of months ago when I got worried about this. The dip stick you have probably has a safe range, safe between two marks. If you have the right stick, and if the level is between those two marks, I am told you leave it alone. Do not add just because you are i the middle of the range. I urge you verify, not just rely on what I am reporting but it is what I was told.
Mine was overfilled about a quart or two one time. I was going to drain some out and was warned, be very careful. You could have a lot of oil on the floor in a hurry, better to return to the service folks and let them do it. On the other hand the small amount over was said by technicians to not be a problem due to the type of sump we have in the ISM. As to pressure, I run about 35 - 37 psi at 65 mph and around 25 at low idle. Service technicians say that is a little in the higher range of what this engine runs, on average, you might see a bit lower. Mike
With the 10 gal oil pan, I would rather run 4 qts low than 2 qts over filled.
FWIW
Dave M
Greg, I too have the same ISM as you and it runs in the 25-35 psi range. I've never had the red light come on or pressure drop to near zero. The engine has 96k miles on it.
My light comes on at 21 psi
I think I would put a certified direct reading gage on the engine to find out what the engine oil pressure really is.
Answer for me is the VMSpc, In our business with automatic engine controls, sometimes we find both oil and temp gauges not reading good, some gauges are tied in with the shutdown, gauge reading and warning indicators. About 99.99% are corrected by moving/tightening the sender to make a better grounding to the engine. On others, the wiring harness to control panel / dash has poor connections.
FWIW
Vmspc should be accurate as well, at least I'm my 1999 ISM the dash gauges were innacurate, but I didn't care since the vmspc was in range and accurate
My Silverleaf is accurate as well.
How or where does the Silver Leaf get it's pressure information?
Of the ECM for the engine if you have an electronic cummins. My Factory VDO gauge on my 1999 U-270 (ISC 350HP) showed anywhere from 200 - 250 and at 230 the engine should have shut down. Panicked I went to Cummins in Nashville, they read the computer and said "this engine has a lifetime high temperature of 208 degrees" (that was with about 85,000 miles on the coach at the time. Tech said engine would go degraded mode at 220 (as I recall) and shut down at 230 (again as I recall), all via the ECM.
Drove home, bought silverleaf, never looked back. Guages in the u-270 were vdo and maybe I had corrosion or bad grounds or ???. Silverleaf a great piece of mind. Interestingly, although not as good a resolution (degees temp, pounds pressure, etc.) the gauges in my 2000 U-320 ISM agree 100% of the time with the Silverleaf, just have much better piece of mind with Silverleaf
Gets it from the engine's ECM, and the ECM gets it from a sending unit on the engine somewhere.
Wish I had a Silver Leaf for my Cummins 5.9, but it is a mechanical engine.
On electronic Cummins engines, different sensors feed the ECU and dash gauge.