ezone

I've done this to a few of my cars over the last 3 decades.

gearbox

iTrader: (95)

if you dont mind the cold, leave the heater control dial on 'cold' in the winter. car warms up way faster than even if the dial was set to 'hot' with the fan off. faster it warms up, the faster you get better mpg.

DodgeCivic

This is a great tip! Where did you find this out?

ezone

It's sort of common sense, once you understand the "hows and whys".

A LOT of extra fuel is needed to sustain operation of a cold engine (can easily be double, depending on conditions), and a lot of fuel is consumed while getting the engine up to operating temperature.
The quicker it reaches operating temp, the sooner it reaches optimal efficiency.

You sitting in the drivers seat, trying to suck what little heat the engine has already made can significantly increase the time it takes to reach operating temperature.



My daily commute is only like 6 miles each way. My engine barely gets warmed up in the winter.

gearbox

iTrader: (95)

at least on our cars, switching to "cold" temp on the dial actually closes off the entire heater core cooling circuit. that way coolant only stays in the engine until it warms up enough to open the thermostat and use the radiator. with the heater valve open, coolant circulates thru a good amount of hose and thru the heater core, which still gets cold air blowing with the car moving, even with the fan off. this acts as a mini radiator. ive driven in areas so cold that the engine will never warm up unless the heater is set to cold and youre driving in 3rd gear. another trick to warm the auto trans faster is put it in D with the ebrake on while you let the car sit. this usually needs the car to be parked on an upward incline, otherwise it will prolly start rolling forward.

ezone

8th and 9th gens don't use a water valve. 7th was the last to use it.

gearbox

iTrader: (95)

oh okay, at least for MY car lol. what did they end up switching to, just a mix door to block the hot air?

ezone

Yes.

But IMO the effect would still be the same: If you keep the heat turned off, then you aren't removing it from the cooling system. Thus, slightly faster warmup time.

gearbox

iTrader: (95)

i suppose, since the air has nowhere to go. but i like the valve design better, like making a bypass rather than having a whole other system for coolant to flow thru (altho it decreases the chances of cracking the block, since with the old system you could warm the car up first and then turn the temp dial to hot, causing the ice cold coolant to enter the engine). i guess like anything, if used properly it will work out.

cnyankee

New to forum. From Cali. Just bought new 2012 civic ex and only getting 20mpg city. Car has 200 miles on it. Dealer said that I have to drive it for at least a month for the car to get use to me. That statement does not make sense. I never expected 28 mpg like sticker said but at least 25 city. Thanks

YamaDharma

Bought Civic LX Jan 2, 2012. Drove 15,248 miles thru 12/31/12. Approx. 75% hgwy. One trip to NC and back to CT, 1820 miles. Overall fuel mileage for year was 36.3 mpg. NOTE: hills where I live kill "city" mileage. Rated for 28 mpg, but I estimate 25 mpg pure city due to hills. Good vehicle so far.

trogg1

I live in upstate NY and purchased my 2012 Civic LX auto in May. I drove a lot of highway miles in the summer/fall and easily got 32-40 MPG. However, this winter doing mostly city driving, I've got 22-24. I drive with a light foot and I'm quite disappointed in the low MPG. Otherwise, I like the car.

EX-Dave

Glad to see my original thread has grown.

Anyway, I've had my 2012 almost a full year. I got about 17k miles on it. The gas mileage is excellent. I've pulled 42 MPG on a highway trip. Even during these cold winter months in New England, I'm getting like 25 on average doing short city trips around town. One of the keys to getting decent winter driving mileage might be not to let the engine idle out in the driveway. When you do this, you are getting zero miles to the gallon.

I get a kick out of watching the gas mileage climb and decline on the Info screen as the driving conditions change.

DocViking

Before I purchased my 2012 Civic in August I was driving a 2002 Acura MDX, filling up twice a week @$70 a pop. Now I pull 32mpg commuting to work (rural hills and some hwy) and on longer trips I have pulled 42 mpg hwy with no luggage or passengers. And I only fill once a week for about $35. The car pays for itself compared to what I was spending