Does dirty oil bring down mpg?

[Koojo]

Its been about 3000 miles since my last oil change. I have scheduled it to be changed in a few days. I looked at the oil in my engine, and it seemed really dirty. Would dirty oil make your car waste more fuel? Because it seems to me that my mpg went down these past week or two. Thanks

[DVSNCYNIKL]

It can affect the performance of your engine which might cause it to decrease mpg. Just get the oil change and you should be fine.

[Koojo]

Oh ok, Ill just see what happens after the change. Thanks

[urasula]

engine oil is to lubricate and reduce friction between the piston and the engine block. it's a good habit to get ur oil changed every 3k. it's all part of car maintaince to prolong the life of ur car.
so dirty oil won't really reduce ur gas milage, but if u don't get it changed u run the risk of damaging ur engine which in-turn may cause u reduced gas milage.

[i_rebel]

actually, mpg will be affected by dirty oil . . . i believe the difference would be negligible, though . . .

after all, your engine's made up of moving parts and the oil is there to lubricate these parts. clean oil will flow freely within the engine, dirty oil will produce more friction . . . friction is bad.

your engine will be less efficent, hence lower mpg figures . . .

[Koojo]

I changed my oil today, so maybe Ill see better results. Thanks