outside temperature cause the gas mileage to drop?
#1
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2006 e320 cdi
outside temperature cause the gas mileage to drop?
I have my car of a couple of years, but I don't remember in the past, the gas mileage drop 10% in the winter. Perhaps, I didn't pay that much attention. But is there any logical explanation on lower outside temperature would cause the car to use up more fuel? Thanks!
Last edited by anewbie; 12-08-2011 at 01:06 AM.
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2008 E550
I will say however.. I've been told to fill up at night when its cold as you will get more volume of gas.. or something along those lines... maybe someone else can fill in the gaps.
#3
Senior Member
I drop every year once it gets near freezing or below. I'm talking from 29 to 31 in summer to, as of yesterday, about 25! I'm using C and liters/100km. It was -10C yesterday morning and I burned 9.1L / 100 Km. Last fill up I traveled 90% hwy @ 65mph cruise set and only managed 8.8l/100 or about 26.5mpg.
I also fill up in the early morning because it is when the fuel is at its coolest from cooling off all night. This really only matters a tiny bit and during the summer. Doubt it warms very much right now no matter what time of day it is.
I also fill up in the early morning because it is when the fuel is at its coolest from cooling off all night. This really only matters a tiny bit and during the summer. Doubt it warms very much right now no matter what time of day it is.
#5
Super Member
Colder air gives ya more HP due to density and if you did not adjust the tire pressure, the tires will loose volume and create more the drag.
#6
Good grief, Charlie Brown. It's colder. The air is denser. The ECU therefore feeds more gas to the injectors to maintain the proper stoichiometric ratio (a function formerly performed by the archaic device known as a choke). It also takes the car longer to warm up, and the gas used in the winter is modified and gives less power, therefore requiring more to travel a given distance.
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2013 E350
My experience is that it is not linked to the cold weather, but rather to the winter blend of gasoline used between October and April. I also see about a 10% drop in mileage.
I'm sure there is a temperature component as well as a behavioral component as we let the car warm up a little longer, but the gas blend is the real issue since it is not very cold in October or April and there is an immediate decrease in mileage.
JK
I'm sure there is a temperature component as well as a behavioral component as we let the car warm up a little longer, but the gas blend is the real issue since it is not very cold in October or April and there is an immediate decrease in mileage.
JK
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1991 F-150, 1976 912E, 2006 E500 Wagon
Two points to ponder:
1. no one has yet mentioned the thickening of the lubricants in the drive train, especially the differential(s) -- not such a big factor if you use all synthetics, nowadays, but really important way back when.
2. this filling when the gas is cold trick is irrelevant -- the tanks are buried deep in the ground nowadays, not standing on stilts alongside the pumps, and down where they are the temperature just doesn't change that much, except in the far North.
2. this filling when the gas is cold trick is irrelevant -- the tanks are buried deep in the ground nowadays, not standing on stilts alongside the pumps, and down where they are the temperature just doesn't change that much, except in the far North.
Last edited by Ichabod; 12-08-2011 at 12:11 PM.
#9
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It's definately the winter blend. 10% drop is normal.
#10
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It's also because it takes the engine longer to reach normal operating temperature when the weather is colder. The car burns more fuel until the engine reaches normal temp, the aforementioned electronic equivalent of a choke. So you are driving more of your normal commute with the "choke" on, resulting in lower miles per gallon.
Always looking for ways to entertain myself, I tried turnining off the heater in my 210 chassis E320 until the engine reached normal operating temperature. This would allow the engine to warm up sooner, because heat was not transferred from the engine coolant to the cabin of the car. I wanted to see if this affected the reported MPG on my 7 mile suburban commute to the office. It seemed to make a small positive difference - 0.2 or 0.3 MPG increase. Of course, I got tired of having cold feet, so I did not continue this practice...
Always looking for ways to entertain myself, I tried turnining off the heater in my 210 chassis E320 until the engine reached normal operating temperature. This would allow the engine to warm up sooner, because heat was not transferred from the engine coolant to the cabin of the car. I wanted to see if this affected the reported MPG on my 7 mile suburban commute to the office. It seemed to make a small positive difference - 0.2 or 0.3 MPG increase. Of course, I got tired of having cold feet, so I did not continue this practice...
#11
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I only let idle till the RPMs drop below 1k. Usually about 20 or so seconds. Then I move very very slowly, annoying cars behind me :-). I do not let the RPMs get past 1600 till the first temperature marker lights up. Then I slowly accelerate only about 100 to 150 RPM for each of the next temperature markers that light up. Once I'm about at normal temp; usually about 5 minutes of easy driving on the HWY, I go to normal speed and turn on the heater. I've spent countless hours of research and opinions about this method being far easier on the engine than simple idle. Idle takes too long to warm engine and fluids. More damage that way.
#13
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I only let idle till the RPMs drop below 1k. Usually about 20 or so seconds. Then I move very very slowly, annoying cars behind me :-). I do not let the RPMs get past 1600 till the first temperature marker lights up. Then I slowly accelerate only about 100 to 150 RPM for each of the next temperature markers that light up. Once I'm about at normal temp; usually about 5 minutes of easy driving on the HWY, I go to normal speed and turn on the heater. I've spent countless hours of research and opinions about this method being far easier on the engine than simple idle. Idle takes too long to warm engine and fluids. More damage that way.
#14
Senior Member
Thanks for noticing. Made my day. I really spend a lot of time ensuring my car runs and looks as good as new. Engine compartment looks almost as good as new, I wipe it all down every time I wash the car which is often . A few times a year I remove wheels and clean inside wheels, suspension parts, and dress the rubber and plastic parts. Its almost too much, almost.
#15
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Good grief, Charlie Brown. It's colder. The air is denser. The ECU therefore feeds more gas to the injectors to maintain the proper stoichiometric ratio (a function formerly performed by the archaic device known as a choke). It also takes the car longer to warm up, and the gas used in the winter is modified and gives less power, therefore requiring more to travel a given distance.
FWIW, I had nearly identical experiences with my previous '04 Jag XJ sedan...29-31mpg hwy in summers; 25-26mpg hwy in cold weather.
During the winter months, we would migrate back to the upper Midwest for the holiday season, and I could easily note the drop in mileage as we exited the warm weather of Florida/Georgia and entered the cold environs of TN/KY/OH enroute to the Chicago area.
relinuca
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2006 e320 cdi
I only let idle till the RPMs drop below 1k. Usually about 20 or so seconds. Then I move very very slowly, annoying cars behind me :-). I do not let the RPMs get past 1600 till the first temperature marker lights up. Then I slowly accelerate only about 100 to 150 RPM for each of the next temperature markers that light up. Once I'm about at normal temp; ...
#18
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'01 W210 E320 CDI
The W212 (at least the CDI models) have shutters behind their grille, operated by the ECU totally not allowing any cold airflow over the engine block until normal operating temp has been reached and the thermostat is open and the radiator is heated up...
Because of this I wonder if closing ( or half closing) my grille is going to make a difference during winter...
Because of this I wonder if closing ( or half closing) my grille is going to make a difference during winter...
#19
The W212 (at least the CDI models) have shutters behind their grille, operated by the ECU totally not allowing any cold airflow over the engine block until normal operating temp has been reached and the thermostat is open and the radiator is heated up...
Because of this I wonder if closing ( or half closing) my grille is going to make a difference during winter...
Because of this I wonder if closing ( or half closing) my grille is going to make a difference during winter...
#20
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1991 F-150, 1976 912E, 2006 E500 Wagon
Those shutters on big trucks are thermostatically controlled;
(by coolant temperature, not outside air temp.) that's why they flip back and forth from one message to another (not by the driver pulling a knob just for the fun of it) while the truck is sailing down the interstate and this has a big advantage in allowing full coolant flow all the time to keep the block and head temperatures as even as possible. Actually, Lancia cars used the same system instead of a coolant flow thermostat until about 1965. My Lancia Fulvia coupe was a 1966, so it had a regular coolant flow thermostat, but my owner's manual still explained how to service the shutter type.
Last edited by Ichabod; 12-13-2011 at 07:08 AM.
#21
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I don't know about you guys, but my little W211 has shutters on the bottom of the bumper. The entire bottom opening closes when its cold, don't know how cold it has to be to operate it but I've seen it many a cold days closed. Its really cool.