Tommly

iTrader: (2)

Hey guys,

I just changed my oil on an engine with 141k miles to mobil 1 extended mileage 5w30, and my mpg dropped at least 10%, what gives?

I'm pretty sure it was running conventional 5-30 before, but the manual called for either. This is a Nissan 3.0 V6, but it's making me wonder about what I put in my LS1 (redline 5w30).

I would really appreciate a little explanation.
Tom

chavez885

iTrader: (12)

So...what kind of data did you create to make you think you lost "10%" mpg. That could easily be fluxuated by driving habits, tire pressure, outside temp.

Tommly

iTrader: (2)

Good point...to be honest I wasn't that rigorous, but I make this 350mile drive about every other week on cruise control all the way. I gas up at the same station and arrive at the same location, and there was a significant drop in where my fuel needle ended up this time. The only factor I changed was the oil. Maybe I should sit on it?

LS2TA

i would try changing the fuel filter and doing a fuel tune up might be the answer

LS1crazy01

iTrader: (14)

Yah 10% is nothing big. Thats probably just the driving conditions or somthing. I dont think its a good idea to switch to synthetic after running conventional for so long. Synthetic can cause things to leak when you switch like that. Just my opinion.