MPG plummeting

[winnie]

When I first got the car it was going around 28 miles. Recently I've notice the MPG is declining to 24. Is that normal? Does excessive heating have an affect on it as well?

-PS I don't drive it like a maniac.

 

[Natesriv]

heating?

city driving can lower it, winter gas can lower it (often times with more ethanol), or engine calibrations made by the car's computer as a result of some anomaly. mods, etc...

tire pressure too!

 

[winnie]

I turn my heater to the warmest, I wonder if that will eat extra gas. I got this car a little over a month ago so I don't know much about it. I'll test it out for another month and see if there is any changes.

 

[blutrotsonic]

The explosions in your engines cylinders create heat. The job of the cooling system is to cool the engine. At a certain temperature coolant circulates through the radiator to be cooled. When you crank the heat, that warm coolant flows into the passenger compartment and passes over a fan to warm the cabin. Allowing coolant flow into the cabin instead of 100% percent into the radiator will not require more gas. Turn up the fan speed and you draw more current which means the engine has to work just a little harder.

 

[Natesriv]

No running heat won't affect your MPG's by that amount. Gas engines (the gasoline combustion cycle) is more efficient at hotter temps, but running your heat won't make that much difference.

If it's under warranty they can certainly check it out at the dealership for free. If it's due for a service many local shops can help too...

 

[River_Rat]

To the extent that many individuals turn the vent selector knob to the windshield when using heat, there may actually be some impact on mpg. I have read that selecting the windshield setting forces the a/c compressor on in order to dry out the incoming air and prevent windshield fogging.

 

[Natesriv]

if the temp is high enough, the compressor will come on regardless of driver input when the defrost is selected. ... but that's a poor way to heat the interior though..

 

[winnie]

Update: My current MPG is at 17 at best

To give you guys an update from a couple years ago. I got my car pre-owned, the MPG was alright at around 23 before declining to 16-17 (I'm from NYC but I do drive upstate) and the temperature gauge was inaccurate (-20 degrees during summer).

After countless service checks, they managed to locate the issue of the temperature sensor to a loose wire. However, I still cannot figure out the cause of the low MPG indication although I don't fill up my car that often. I've searched far and near and most drivers have at least 25 MPG.

Has anyone ever encountered this issue?

Once again, it's been over 3 years and I don't drive like a maniac. I drove around 65 to 70 mpg to Virginia and I don't believe the gauge increased at all.

 

[SuperFudd]

Temperature gauge? What temperature gauge?

The mpg reading is not likely to change unless you reset it. It gives an mpg average.