Increased fuel consumption in winter weather?

feelites

Just wonder does anybody noticed fuel consumption increase??
especially during driving on the snow?

I found that im doing much less MPG than in dry condition.

How about yaz?

Absurdum

traffic is heavier and slower
heating is on a lot more
people let the car warm up before driving off....

doOh

... and when engine is cold and u start it, it eats up lot more petrol than when its warm.

zilog_jones

Yeah, I notice about a 5 MPG drop in city driving in the winter. Engines take longer to warm up, so will increase fuel-air mixture for longer just like back in the days of carbs and manual chokes

Rear window demister is drawing like 150W+ off your alternator, and you'll have your lights on more regularly too (another 150W or so for dipped beams + everything else).

Heating is usually drawn from your engine's coolant system, so the fans are the only real consumer there - however, if you're putting the fans on max and the heat on full when you get in the car you're going to make it take longer for the engine to warm up and it'll take longer for any heat to get to you.

Senna

yeah my mpg has dropped a good bit, but i cant expect any better when in the snow i'm driving at 30mph, spending long times in low gears, letting it run for 15 minutes in the morning before i go out.

shamwari

Trying to troubleshoot a fault earlier in an Opel Astra. At 50mph on the motorway (external air temp was 1.5c) and the engine was struggling to reach a coolant temp of 70c, even though the thermostat was ok. It was the cold external temps that were preventing the engine reaching correct temp. If the engine temp is marginal like this (below 65 / 70 degrees), some cars will not go closed loop, and this will keep the mixture rich, and the fuel consumption up.

zilog_jones

Maybe blocking the radiator would help in cases like that?

fryup

Absurdum wrote: »

traffic is heavier and slower
heating is on a lot more
people let the car warm up before driving off....

does using the heater effect fuel consumption as much as say air con does in the summer?

zilog_jones

zilog_jones wrote: »

Maybe blocking the radiator would help in cases like that?

Yeah, until there is a crash up the road and you are sitting in a traffic jam for an hour with a blocked up rad (how would you block a rad anyway, jam the stat shut or something ?? )

zilog_jones

RoverJames wrote: »

how would you block a rad anyway, jam the stat shut or something ??

Cardboard in front of the rad
It's not something I've tried myself, not sure how much it affects temps when idling.

Chippy01

RoverJames wrote: »

how would you block a rad anyway, jam the stat shut or something ??

Just cover the inside of the grill with something; vinyl sheet, cardboard, or similar.
Canadians do it all the time to keep their engines hot in the cold weather.
Google vehicle radiator grill screens....:)

zilog_jones

Canadians have electric block heaters too but you kinda need them when it goes below -20...

zilog_jones

zilog_jones wrote: »

Cardboard in front of the rad
It's not something I've tried myself, not sure how much it affects temps when idling.

Oh, I thought you meant block it so the rad circuit wouldn't feed into the inner loop

Voodoomelon

Consumption has gone through the floor, that normally reads 22-23MPG with the exact same roads and distances travelled.



Note the temperature!

Matt Simis

To the OP, rolling resistance vs Snow and Ice (not the sheet black ice, the large lumps of it) presumably increases the drag of a vehicle massively too, leading to large drops in economy.

Regarding blocking of the Rad, I was considering this too as new to me '98 S8 appears to have a stuck thermostat. When trudging along in traffic at 40mph ish its only getting to just over 80degrees. When on the open motorway in this weather, its at 70degrees. I know its cold, but IMO the 'stat should be doing its job and maintaining near 90. Or am I expecting too much?

For blocking I was thinking maybe covering 30% with cardboard till I get the 'stat changed over.

Voodoomelon

I'm not sure about A8s, but mine is rock solid temperature, it shouldn't fluctuate like that IMO.

EDIT before abuse: S8s!

Matt Simis

Matt Simis wrote: »

Or am I expecting too much?

For blocking I was thinking maybe covering 30% with cardboard till I get the 'stat changed over.

Nope, you're not expecting too much. Petrol cars should still reach 90 degs quite quickly once motoring. Your stat is prone to not closing.

NewApproach

I have, but that's just because I leave it running for 10/15 minutes in the morning while I'm having breakfast to defrost windscreen/heat up the inside.

congo_90

down from 46mpg to 31.4 at best.
for those who want to warm the car quicker put heater on full cold and allow to run(obviously engine on). this will warm the engine faster thus you can adjust stat to hot sooner.

the heater fan typically affects fuel consumption from 12 to 25% depending on diesel or unleaded. as others said rear demister, headlights and long times in slow traffic also play havoc