I noticed my mileage has slipped some recently. Changed fuel filters etc. Not really enough to worry about I guess but I was getting some really good mileage. Only thing that changed is on my last oil change I switched to the MOOPAR HD 15/40 Premium diesel oil. Was using Delvac before. COuld this have an affect??? Thanks!!

 

Sounds like you are using the same viscosity. That being the case, I would have to say no. I am no expert however, but I jsut do not see how. I would not think between 2 different oils, but the same viscosity would have a noticeable drop in fuel economy

 

Makes sense... My biggest culprit I think is my new work location. I am a teacher and transfered to a school only 4 miles from my house instead of 20. Truck used to get warmed up every morning up to running temp. Now she only gets driven 4 miles to work and barely gets off the cold line. But this was not a recent switch... Been here for a few months now.. But it has gotten COOLER outside temp so maybe that has something to do with it.. I am glad I tow hard on the weekends as I know it's not real good to go short distances and stop.. thanks!

 

As stated.... same viscosities will make no noticable difference in mileage.

RJ

 

Now THAT sounds more like the problem right there. Your truck needs to warm up some......

 

i switched to synthetic. i was skeptacal at first, but my motor is alot quieter now! its hard to keep accurate mpg records becuase my driving style changes from mood to mood and i seem to always have my boat hooked up.

brett

 

Your truck needs to be worked! Blow out all the gunk that is in it.

 

I hope that was not referring to me ( Your truck needs to be worked)... LOLOL My truck pulls a LARGE Living quarters horse trailer every few days and pulls it hard in really hot weather

 

I agree completely! It HAS to warm up completely to be efficient. ESPECIALLY DIESELS!! Your Cummins motor was not designed to commute 4 miles to work: it was designed to WORK! Drive a rice burner to work. It will warm up faster, and get much better mileage.
Mike
###