[mnmega]

Hey guys I just picked up a 04.5 and I have w oil psi question. To be honest I never really looked at the gauge until last weekend when I was on my way home from tx with a decent load on it. Anyway while driving loaded or not it reads a little above 40psi but at idle its closer to 25psi. I thought it maybe just needed the oil changed, so I took it to the stealership and had it done. Still reads the same. I bought this from a good buddy who has owned it since new and never beat on it. It has 163k on her. Is this normal or should I be looking into it more? Thanks

 

[mnmega]

anyone? whats your gauge say or doing?

 

[rgaskell]

I believe Cummins allows a min of 15-12 psi before going into the engine.

Just sounds like your truck has some wear from those miles. Keep a eye on it and if it gets worse then start getting worried.

 

[TJ_mopar]

Others have posted on this, but from what is discussed on this site it USA dummy gauge. Basically as long as there is more than 5 psi of pressure the gauge will show a predesignated pressure based off of temp of the engine and rpm. Mine shows a little over 40 till it reaches full temp, at that point it shows 30 at an idle and 40 when over 1300 rpm.


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[papaduck]

The in dash gauge is a fake. It is controlled by the computer based on RPM and engine temp and at least 6psi pressure. On starting the engine the gauge will show pressure for around 30 seconds even though there may not be any oil pressure. The ISB engine will actually have no pressure for 3 to 4 seconds on a cold start. Actual pressures on a good engine will be from 10psi to 80psi depending on the engine temp.

Dodge put this fake gauge in to keep owners from worring about the oil pressure because of the big swing in pressure. How many of you would freak out if you saw 10psi on a hot engine? Most will idle at 15 to 20psi on a hot engine but 10psi is still OK.

If fuel is getting into the crankcase the oil pressure will start dropping but the in dash gauge is not going to show the drop. This is why I added an oil pressure gauge.

 

[Glidehm]

I have an autometer oil pressure guage, and I can tell you that the guage on the dash is a waste of time! I see 60-70 psi on cold start. This is when I have the truck plugged in at night. After letting it warm up for five mins, the oil is still cold and hits 80psi when driving easy. Im sure this is the bypass working. When the oil is warm and truck is cruising around 60-80mph, I normally see 40-60 psi depending on ambient temp. During the summer with hot oil and ambient temps above 100 after towing, the lowest I have ever seen at idle is 20-25 psi.

 

[chip61]

I've driven a lot of diesel trucks (larger trucks) and mine is the only one that shows consistently 40-45psi oil pressure no matter what. Now I know why. If it's no more accurate than that, they may as well give us an idiot light!

 

[verdesardog]

I've driven a lot of diesel trucks (larger trucks) and mine is the only one that shows consistently 40-45psi oil pressure no matter what. Now I know why. If it's no more accurate than that, they may as well give us an idiot light!

EXACTLY! all that gauge is is an idiot light without the light!

 

[SEAN06]

Do not take the stock dummy light serious.these motors can vary from 20 to 90 psi.

 

[ykdave]

idle pressure can be as low as ~10psi, which is of no concern, but of course if oil pressure doesnt rise with rpm, youve got a problem. with just a little bit of rpm, oil pressure should jump to ~30-40psi on a warm engine (spikes near 100psi on a cold engine arent unusual)

A good rule of thumb, is 10psi oil pressure for every 1000rpm and your gravy, nothing to be concerned about

 

[mnmega]

Thanks for all the replies guys. From the sounds of it I'm should be just fine. I wws just a little worried because I'm hauling a big load to southern cali and back on the first of Feb.

 

[DieselTech77]

The Cummins ECM on ISC and ISL's will show 55.1 psi as long as the oil pressure switch reads 6 psi or above. So on the ISB's its a probable assumption to say that if the oil pressure sensor/switch see's 6ish psi or above it reads 40 psi. When I plug into an ISC or ISL with Cummins Insite I can sit there at idle and then put the throttle till it hits the governor and INsite always reads 55.1 psi while the mechanical guage will go anywhere from around 20 psi to 90/100psi.

 

[DieselTech77]

bump....mess with it at all?

 

[papaduck]

Not sure by what you mean 'mess with it at all'.

I have added a real oil pressure gauge and recommend adding one. Especially if you are running a pressure box. If an injector fails and starts adding fuel to the crankcase the oil pressure will start to drop but the indash gauge will not show this. If on a trip and your oil becomes diluted you can destory the engine before you will know that you have a problem.

At work I had this happen, the vehicle had a real gauge and I saw that the oil pressure dropping and took it back to the mechanics. The crankcase was overfull with fuel. The engine was saved and is still running years later. There have been others that have lost their engine because of this very problem.

 

[DieselTech77]

Sorry, have you found out what is wrong yet? Is that better papa bear?