Just had did a 5000 mile oil change on my 2004.5 Cummins. Put in std. Shell Rotella and a new filter. Dealer performed work. Also they greased the two tie rod ends after I questioned them about it and then had to show them where they were! Next time I do the work on the truck!!!!!

Anyway I reset the trip computer after leaving the shop and before heading home on a 45 mile trip. The truck got around 21 mpg!!! Max speed was around 65 mph. And varied from stop and go to highway driving. Before the oil change, truck got around 18.5 on the same route. I am headed on a 100 mile mostly interstate trip on Thursday. It will be intresting to see what mileage I get.

After the oil change there has been an increase in crankcase breather odor. I am wondering if the case was slightly overfilled. Anyone had a similar experiance????

 

Shell Rotella has a strong odor for a couple of hundred miles. It'll fade... Don't know why the increase in mileage. Are you sure they didn't do a flash on your ECM while they had your truck? The Cummins came with Valvoline Premium Blue from the factory. It should be similar enough to Rotella to not make a difference. But if it did, I won't argue with success!

 

Hannibal,

I do not think they reflashed my ECU. I kept an eye on the truck. Seemed just like a normal oil change. In fact I don't know for sure if they even did the normal checks such as washer fluid, etc. They seemed in a hurry to get home!

I really don't understand why the oil would effect mileage. And I make my living understanding machinery! But so far the oil change has effected the mileage. Very weird! But also very good!

 

I just don't trust that darned computer read out. On a 1100 mile trip, last week, the best that the computer read was 17.3, calculating by hand=23.4 mpg! Sometimes comp reads 18.5 or 13.5 on a long trip,and it always figures out to be low 20's by hand. ( getting nearly 600 miles on a tank, running around 65mph).Tried resetting, tried leaving it be, never makes a difference, it's always wrong,but I can't keep my eyes off of it, thinking my mileage sucks...so I stick on the compass and thermometer,and crank up the tunes!

 

I have hand calculated my mileage at every fill up. And the trip computer MPG prediction is always within .5 mpg of my calculations. Until it does agree with my calcs. I will continue to be drawn to its green light! But I do agree. It is better just to switch to the compass!

 

Just fueled tonight and my run is only about 15 miles. After fueling I reset the trip meter and the mpg meter, ran 2/10ths of a mile to Schucks Auto Parts and went in and dumped the oil from my 5000 mile change. Schucks has the Premium Blue for $7.50 a gallon so I know where I will buy it from now on. I then headed home and with waiting to turn onto the highway and stop at 1 traffic light by the time I hit 6 miles mileage was reading 16.2, speed was 55mph. I pulled into a DOT weigh station and with no passengers in the truck it weighed in at 8340 lbs. That is about 500 lbs more than I thought. I guess the last time I weighed it I didn't have the toolbox and hitch installed. By the time I passed through two small towns at 35 and accelerated back up to a bit over 50 and about 4 blocks of 25 mph and a stop sign I was reading 17.3 mpg when I shut the truck off. Averaging my last two fill ups I'm just over 20 mpg and that is hand calculated with 5900 miles on the truck. I think that is pretty good for over 4 tons of vehicle.

 

Steve, that's great, and it works out to about 21 mpg,(17.3),24 mpg(20) for Canadian(Imperial) Gallon!

 

My problem too, is the computer is reading in U.S .mpg, not Imperial, so that's a 3-4 mpg difference right off the bat.

 

Steve,

Your scenario sounds identical to mine!!!! So I am not the only one that has noticed a mileage increase after an oil change. I wonder if this trend will continue? I would love to know why this is happening. I will have to ponder for awhile......

 

if its up there please forgive me, but how many miles are on your truck?

Do you mean did A 5000 change or "The" As par the break in or what not


Please let us know haha

 

Well I drove the truck today. Mileage has improved but not as much as I first thought. However I will run a 5 hour interstate trip on Sat. I will do a mileage calculation afterward to find out what it is. The trip will be the trucks first totally interstate run without city traffic, trailers, country roads etc. I am very curious to know what kind of mileage I will get.

kingofdodge7131 - > The oil change was at 5000 miles on the odometer. Truck has around 5120 miles on it now. It was my first oil change.