I have a 99 Cummins with 109,955 miles on it. I have noticed I had white smoke coming out of the blow by tube but not anything noticeable unless im stopped for a few minutes.  if I take the oil cap off it blows a little white out of it but not like clouds of it.  So next I did the oil cap test and removed it and flipped it upside down and it didn't bounce around or move (except a little due to vibrations of the engine).  the truck runs awesome no lack in power perfect pick up and go, it doesn't smoke except a little black on start up and doesn't eat coolant or oil.  No knocking either.  The oil pressure is around 30-35 at idle and at normal cruising speeds of 55mph at around 1800 rpm its around 40-42 and the temp never rises above 192.  my question is, is this normal im new to Cummins and should I worry

Your oil pressure is good for idle but for high speed I think it is low. I know my Cummins oil pressure is about 70-80 pounds at 60mph. I am not saying you have a problem, just mine is different.

80PSI!   That's high. I didn't realize the gauge even went that far. Mines closer to the OP. A little blow by is normal and it sounds like your fine. But a  vacuum leak will cause it also. Does your 4WD and heater vent door work?

over 40 at idle and goes to about 65 psi on the road.

Yes the 4x4 works good doesn't like going out all the time and the heater vent seems to work good I use the a/c and it switches fine if I stomp on it it will get closer to 55-60 but never over that also when I first start the truck for the day the oil is at about 42 psi but drops to about 35 when warm. truck doesn't hesitate at all

Edited August 6, 201510 yr by 99rcummins

I don't think you have anything to worry about. A little smoke is normal, many report it, and you're not blowing the cap off. My PSI is very similar to yours. Check it in another 109k when it's finally broken in and it might be even better.

Thanks for the replies I think it's an issue only because I have a 7.3 Ford idi that had blow by a bit worse and ended up having bad rod bearings, rings and valves so I'm a bit apprehensive when I see this its a beautiful truck never beatin it was used all its life for transporting two Morgan horses I love this truck and just have to check but you all know how I feel because you to love the Cummins

Edited August 6, 201510 yr by 99rcummins

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Everything sounds good to go. She's not a Ford!

Everything sounds good to go. She's not a Ford!

 

 

You're right the bigger issue is likely the dash with a gaping hole in it

You're right the bigger issue is likely the dash with a gaping hole in it

What's wrong with that? Gives the flies a place to collect. 

Mine fits my US map pretty nicely haha.  

Take off your oil cap while truck is running. Set the oil cap on top of its hole. No blo by and the cap will sit there without moving. Moderate blow by it is I'll flutter. Lots it will shoot up.

Take off your oil cap while truck is running. Set the oil cap on top of its hole. No blo by and the cap will sit there without moving. Moderate blow by it is I'll flutter. Lots it will shoot up.

Just remember that one failed cylinder can pass a blow by test.

^{it doesn't come off at all or barely vibrate}

Sounds exactly like mine but I have twice the miles. Run it hard and don't worry about it.

As far as oil pressure goes put a manual gauge on to really check pressure, sending units will lie about actual psi they are a great indicator of pressure but not actual numbers. As long as the needle is moving up down you are probably OK. I am a little old school when it comes right down to it. Don't fix it if it ain't broke......

My truck, over 220,000 miles

 

Buddy of mine had his 03 CR totally dusted due to a bad air filter and maintenance and was burning a quart of oil in 100 miles and the filler cap test was nill at no load idle or even revved a bit, didn't move at all but it was leaving puddles of oil out the breather tube where ever he parked.

Kind of like...

Kind of like...

https://www.youtube.com/watch?v=6HB3yIoWPLY

Mine is a little worse than that but I'm over 250,000 so I'm not alarmed at all. All 6 run strong. Also my oil pressure is 20 PSI at idle. Cummins states 10 PSI is the minimum at idle so I've got plenty of life left.

Edited August 20, 20159 yr by Vais01

If the sun is right, I can see my vent mod smoking while at a stop light. Looks like michael's. I suppose that plugging the vent tube would be necessary to get a real look at blow by at the oil fill cap.