Synthetic oil, there goes the gas mileage

[Rob_eaton]

well this oil change i went with the Castrol Syntec Blend instead of my usual mobil clean 5000, i noticed my gas mileage went from 27 mixed driving to around 20 highway, i went on a trip to toronto and i wasnt impressed at all

i should say though, it feels more responsive with this oil though

 

[elliot400]

Weird, what does that? I would think a freer motor would yield higher mileage? E-

 

[Rob_eaton]

today i noticed the battery light flashed a few times, then CEL, pluged the predator in and it said something about the circuit power not on required level or something like that...any thoughts?

 

[biminiLX]

oil has nothing to do with your problem

 

[Rob_eaton]

so wat do u suggest?
what should i look for? what might need to be replaced ?

thanks again

 

[Tommy Gunnz]

I had a similar problem bad coil plug wires, I needed to get a new coil plug connector.

 

[Lightningfr]

why do you think oil caused this?
do you have an old bat?

 

[Rob_eaton]

well it was the first time i used synthetic oil, i noticed how smoother the engine felt and also how crappy mileage got so instictively i linked the 2

 

[STG]

Just because one event happens after another does not always indicate causality.

(You really don't know much about cars, do you?)

 

[Rob_eaton]

im no mechanic, but by our car preference, i see that i know much more than you do, go take a turn goin anything over 40 and spin like theres no tommorow mr mustang aka fox fairmount crap

 

[Lightningfr]

im no mechanic, but by our car preference, i see that i know much more than you do, go take a turn goin anything over 40 and spin like theres no tommorow mr mustang aka fox fairmount crap

:lol:

im guessing you never ridding in a stang?

 

[SpeedOften]

:lol:

im guessing you never ridding in a stang?

A Focus will out corner pretty much any stang (minus a full track suspension prepped car).. On any tight technical road course, a properly driven focus will eat through the curves b/c they are able to brake harder and later than mustangs.


Eaton, changing your oil will NOT make your Mileage go down. It is absurd to think that unless you are replacing your old oil with DIRTY oil. Change your plugs, clean your air filter, and dont' drive like a jackass.. Your mpg should improve.

 

[Primaris]

While I approve of the Mustang bashing, give the guy a break. He just asked a question. It's like when you take your car in to the mechanic when you get it back you hear every rattle, see every fingerprint, notice the headlights are dimmer, the tires are square, etc.

Fresh oil won't hurt millage as long as there is the correct amount put in. Too much and the crank will be splashing through it, causing drag and the engine will be spewing oil out the air box. Too little and the engine will most likely only run for a little while. But, if by some chance it was running it would be running hot and with a lot more friction which would cause less mpg.

One other possibility is you broke something while changing the oil. Like say an O2 sensor. Which if broken would lower mpg. I would think you would notice the damage when it was done. But, it could happen while you're under the hood.

The most likely thing is you just think your getting less right now.

 

[Rob_eaton]

my mileage is back to normal, a little less than before but thats understandable with cold weather. I should say that i was in canada using canadian fuel 91 octane when i recorded the bad mileage, as soon as i filled up in the states, my mileage went back up

Speedoften, i had it on cruise control at 65mph and i got around 210 miles in 10 gallons of gas (21mpg), i know this is not great mileage because on my previous trip to new jersey i recorded as high as 34 mpg goin 75mph average...

 

[SpeedOften]

my mileage is back to normal, a little less than before but thats understandable with cold weather. I should say that i was in canada using canadian fuel 91 octane when i recorded the bad mileage, as soon as i filled up in the states, my mileage went back up

Speedoften, i had it on cruise control at 65mph and i got around 210 miles in 10 gallons of gas (21mpg), i know this is not great mileage because on my previous trip to new jersey i recorded as high as 34 mpg goin 75mph average...

interesting... does Canada add anything that the US doesn't.. to their fuel up there??

 

[Tommy Gunnz]

I've never gotten better than 24-26mpg highway with my car. Any suggestions? or is this about the norm.

 

[elliot400]

I bet Canadian has more oxygenators(MTBE and the like) due to thier more extreme winter temps, for emissions sake. Sure to hurt fuel economy a bit. Just an idea. E-

 

[Rob_eaton]

good point elliot, thats my guess too, now im getting 26mpg with mostly city driving with the temps like 10-20 F, cant complain, so yes i think the canadian fuel is either diluted or or has some sort of additives thats being reflected with the poor mileage

 

[VirtualSVT]

The only way oil could drag down your MPG is if you overfilled your engine.

At which point a drop in MPG would be the least of your worries.

 

[Primaris]

I've never gotten better than 24-26mpg highway with my car. Any suggestions? or is this about the norm.

I average 24.5 with a measured high of 28.5 and low of 20.9.