oil pressure at start-up??

[mconstable]

Sorry if this is a stupid question, but all the talk about fluid levels has got me nervous... On start-up, my pressure is to the high end of the safe zone, after warm-up, it hovers in the middle, is this normal? seems kike pressure would be low at start up, and then rise. also,what tools do I need to check diffs and transfer case? Thanks in advance. oh yeah, as far as reading the oil dipstick, there is some oil showing up the stick, as in overfilled, but it's intermittent, not solid like in the safe zone... is this a normal reading? thanks again

 

[nickleinonen]

it seems that the factory oil pressure gauge is a glorified idoit light. works off a 6psi [iirc?] switch and the computer just shows the driver what they [damlier chrysler] want you to see...



i think

 

[Boonieman]

Your oil pressure readings are the same as mine. Any vehicle I ever had would have higher oil pressure when first started up. I always attributed this to the oil being thicker when cold. I know these are supposed to be multiviscosity oils nowadays, but if you've ever changed oil in the wintertime and your oil has been sitting in the garage, it's definitely thicker when you pour it out in wintertime. As far as the dipstick, the tube is so long that it's hard to keep from getting some smearing on the stick when you pull it out to check it. On mine, the "real" oil level is very easy to detect, and I haven't had any problems seeing it. I hesitate to ask the obvious, but you did have the engine off, right? Sorry... I had to ask. Can't help you on the differential/transfer case plugs. I had mine checked at one of those quickie oil places, so I didn't take the plugs out myself. All my lubricant levels were normal though.

 

[DHess]

Dipstick

When you pull the dipstick and have intermittent oil above the full mark, try reading the back side of the dipstick. Usually works for me.



Dave

 

[Cobra]

I agree with Booneman. I can't tell what part of the country you are in but here in Pa when it gets cold at night you will see higher oil pressure at start up. It shows up very much on my Harley. I never (even in the summer) ride off immediately after start up on the Harley. Many have had base gaskets leak on Harleys but I never have. I'm not possitive but I think it is because I wait until the engine is warm and the oil pressure comes down before I ride off. Same thing for my four wheeled vehicles. My . 02

 

[MMeier]

Boonieman, trusting your lube levels to a quicky lube joint? Sounds kind of scary to me!!:--)

 

[Boonieman]

Nope... I didn't trust them to check the differential oil levels. They just took the plugs out and I checked them myself. I explained to them the deal about the possible low fluid levels and if anything needed added, I would have the dealer do it. So, I just didn't pay any attention to what type of plugs were in there. Normally, I do all my truck maintenance myself, but it was really crappy weather out at the time... . and some of the "low fluid level" messages concerned me, so I wimped out and took it to a handy spot. In my younger days I worked at a full service gas station (when there was such a thing), so I am well aware of what can and what does go on. There are lots of great and very reputable mechanics out there. But, bottom line if I don't know them, I don't trust them where my truck is concerned.

 

[RLighthall]

I was just getting ready to post the same question; I know I'm not nuts here. My previous 3 Cummins' (93, 96, 99) all maintained consistant readings - around 40 psi whether cold or hot, idle or cruisin'. My '03 was that way until Saturday, when I noticed that at idle the pressure was just a hair above the lower end of the safe range. Once above 1100 rpm it went to just shy of 40. I did my 5k oil change the Tuesday before, and thought maybe my oil was from a bum batch, though the other half of the case went into my '99 & it didn't act like that. Monday AM when I started the truck, the gauge went to just inside the upper end of the 'safe' range, and above 1100 rpm it went beyond 'safe' range. 20 miles later when the engine was near normal operating temp the gauge hovered around 40, but by the end of the 60 mile trip it was back to flirtin' with the lower safe limit below 1100 rpm. None of my previous trucks acted like that, and neither did the '03 for the first 5k miles. I even checked the oil for signs of aeration but it was fine, as was the level. Anyway, I already scheduled it to with the dealership tomorrow to be checked with a real gauge. I don't know how they'll ckeck it when hot since it takes so long to get to normal temp, and they're nowhere close to a 4 lane which at this time of year is what it takes to heat 'er up... -Zeke...

 

[jlord]

I too was about to post the same message. I have about 1000 miles on my truck, and just noticed that this morning on the way to work. Temps were around 30 degrees.



Maybe this is normal? Please let us know what the dealer says about it.

 

[ntenna]

Guys, nickleinonen is correct.



This is going to burst some bubbles, but the oil pressure readings you are concerned about are just computer-generated simulations. I have the '03 manual, and it is 100% certain, that the oil gauge reading is created by the dash cluster electronics, which takes a 6 PSI (idiot light) closure message from the oil pressure sensor, engine and air temp and RPM readings from the ECM, and generates a reading "within customer expectations".



Engine cold, RPM low or high = high scale reading

Engine hot, RPM high = mid scale (about 40) reading

Engine hot, RPM low = low (about 20) reading



Pressure below 6 PSI, any RPM at all = oil guage at zero and warning light on



Bottom line, judgements based on the dash oil gauge = unneccessary concern. Like all computer-generated images, readings are subject to variations of input, voltage, processor slow-down, etc.



To be sure of your oil pressure, an aftermarket gauge is needed.



We can thank Ford for this. Dodge copied their virtual oil gauge.

 

[RLighthall]

Well, nickleinonen & ntenna had it right. When the diesel wrench at the dealer checked the sending unit, the readings weren't like you'd expect to see from a rheostat-type sending uit, so they went to order a new one from Cummins. Finding that the unit's part number was discontinued, they called Cummins Tech support to find out what's going on. They were told that the behavior is correct, that they no longer use the rheostat type; they've changed to an idiot switch.

So now we have an idiot light which is backed up by an idiot chime now being backed up by an gauge that provides no useful info, other than 'if it moves, there's oil pressure'. Maybe on my survey form I'll suggest to Dodge that they replace the numbers on the oil pressure gauge with a happy face on the right and a sad face on the left and let the pointer pick one or the other...

 

[ntenna]

RLighthall:

LMAO!

New gauge:

 

[rbattelle]

Fortunately, Cummins has provided a 1/8 NPT port on top of the oil filter assembly which simply has a 1/8 NPT male plug in it from the factory. That is the place where a mechanical gauge is to be connected in order to check true oil pressure.



This is good, because it means we can easily connect an aftermarket gauge to that port and be able to read true pressure all the time. Thank you Cummins!

 

[sag2]

I have a question. When was the last time you know of a Cummins that went south because of an oil pressure related failure? Please exclude any failures from non approved filters.



Just as I thought, not very many. So if it has oil pressure when you start it, why not just drive it. At least for the first 100,000 miles.

 

[rbattelle]

Well, there was the Whiteknight fiasco!

 

[sag2]

True, but was it ever decided if the engine was really at fault? My point is, the engine historically does not have oil pressure problems that will result in failure. It appears to be one of the most bullet proof engines ever built.

So I will continue to "just drive mine"

 

[rbattelle]

True. True.