Dwindling milage after first oil change??

[jefflaur1]

2019 3500 tradesman..Okay have you seen this happen? I searched but didn’t see it. Went to a local oil change place and brought my own oil. Motorcraft 10/30 diesel 3 gallons. After the oil change today I noticed milage indicator (usually around 17-20mpg unloaded) DROPPED...even at idle in neutral the digital display went to 4.0 mpg and kept dropping. Truck “seems” to run okay..but that was weird...any ideas? Went home and it slowly went back to around 15-16mpg

BTW my wife noticed oil drips on the driveway but the oil change place re-inspected it and said that the fellow below didnt “clean it up properly”. Does a lot of oil splash that much when draining? Since then seems to be no dripping.

 

[Quyonmob]

Idling it should drop. Idling is 0mpg, so it hits the average hard.

 

[jefflaur1]

I never saw thst happen before. And driving at normal speed it (the average) never changed much..HOWEVER..it is possible that while at the lube place..one of the guys (while trying to reset oil life) might have RESET the average indicator and it was early in the averaging process...hmm and idle brings it down that much that fast? Thanks for the info!

 

[Quyonmob]

I never saw thst happen before. And driving at normal speed it (the average) never changed much..HOWEVER..it is possible that while at the lube place..one of the guys (while trying to reset oil life) might have RESET the average indicator and it was early in the averaging process...hmm and idle brings it down that much that fast? Thanks for the info!

likely just reset as you noted, let’s the numbers fluctuate wildly due to limited data.

 

[Rob2018CTD]

I will say that there is not a good way to do a "clean" oil change. On my 2018 the filter dropped at least 3-4 ounces on top of the splash pan thing under it even with me trying to keep it clean by wrapping a trash bag around the filter before removal. A little wiping up with blue paper towels, and some purple cleaner and it was cleaned up. At an oil change place they don't have the time or desire to keep it as clean as we would like them to. If the drips stop I wouldn't sweat it. Mine left a few drops after I cleaned the snot out of it.