Dirty word....

Clanger · Stirrer Joined: 27 May 2004 Karma :

I know I know....dirty words to use on a biker forum, but I just want to know... if anyone knows....
IF you use cheap oil in your car, does it make a difference to the fuel consumption??

I recently bought Tesco whoopee doozee cheap oil, and now I swear I can see my petrol guage moving down each time I drive...(and I dont go fast, I leave speed to the bike)

Is this just my imagination? Or should I go out and buy some better oil?
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Be who you are and say what you feel, because those who mind don't matter, and those who matter won't mind - Dr. Seuss

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

If its the right grade, or close enough to (10W40, 15W40 or 20W50 are all pretty general grades that could be put in just about anything) and its going into a fairly conventional car, it shouldn't make a significant difference to fuel economy. I think some of the expensive synthetics claim around a 5% difference to fuel economy, tops, so by that reckoning a cheap oil would give you a smaller than 5% loss in fuel economy.

Of course, there are always other factors. If you topped up the oil with cheap oil, instead of doing an oil change, then it probably needs a service anyway. If its a very modern diesel it may want a special oil from the manufacturers.