Winter cold and effects on car

[pletby]

Holy cow guys. Last week we had a nice warm spell just below freezing. I was averaging around 50mpg. Then just after Christmas we got hit with some real cold at -30C. The car felt like I had a stuck brake caliper, or a flat tire. The air even seems harder to push out of the way on the highway. It was that much of a difference. This last tank was around 41mpg.

I haven't been able to track down any mechanical issues and just have to assume it's a frozen block of transmission and stiff lube in my wheel bearings. I suppose it's been a while since I've seen such a big swing in temperature. Maybe I need to get a stick on heater for my transmission too! I'll double check tire pressures as they are most likely down from such a change too.

As drivers who get the maximum from their vehicles, I think we are more in touch with changes in how our vehicles perform. I wouldn't have noticed it so much if I wasn't eoc'ing as much as I do.

[user removed]

From the boiling to freezing points of water air density inreases by 25%.

regards
mech

[BenArcher006]

Same here but not as intense. Last week my UG showed 35-40mpg at 55mph and 8°C outside and today it showed 30-35mpg, same road, same speed but - 10°C outside. I noticed on my UG that my intake temps went from 15-20°C last week to -4°C today.

I'll have to install a front grille block and flush wheel caps to keep the mpg down when it'll be minus 30°C.

[Striker2237]

Well for me personally since I keep my truck in a heated garage I normally gain mpg in winter from the colder air, not much but enough to notice. If you want to have an easier time in smaller cars you should change ALL the fluids and grease (trans, diff, bearing, oil, TC, brakes) to full synthetic so that they don't get a solid in cold weather and come up to operating temp faster. Prevents that feeling of everything in the drivetrain resisting movement for the first few minutes

[Hersbird]

Cold air is dense so while you can make more power it increases aero drag. Around town you may pick up a little on the highway you lose some. My forester is terrible when cold, the transmission and front differential share the same penutbutter fluid and I can hardly get it into first gear. It has a manual. I need to change that fluid, hopefully to something a little more fluid. Like you said, it feels like the brake is still on.

[Striker2237]

When your car has the aero of a brick the more power I get from the air the better lol! Less revs and less gas used, lets me keep revs limited to 1800 on acceleration

[redpoint5]

My parking brake literally freezes when the temps drop, locking up the left rear caliper.

I don't use the parking brake anymore when I know it will be freezing. Instead I leave the car in gear and park on flat ground.

[Cobb]

+1, I do the same when it starts to get that cold. If its going to be icy in the morning I park in 4wd with my lockers locked too.

Originally Posted by redpoint5

I don't use the parking brake anymore when I know it will be freezing. Instead I leave the car in gear and park on flat ground.

[Striker2237]

Might want to check the parking brake is thats happening

[aerohead]

Reinforcing comments already made,and adding to them, colder temps mean:
*engine coolant will never reach temps of summer operation even with the thermostat operating.Thermal efficiency suffers.
*engine oil never reaches an operating temp (viscosity) equal to summer driving.
*transmission fluid or gear oil never reaches temperatures (viscosity) of summer driving.
*differential oil never reaches summer temps (viscosity).
*wheel bearings,u-joints,C-V joints operate under higher viscosity.
*just for all the lubes to reach whatever equilibrium temperature they'll settle in at may require 30-miles of driving,rather than 22-miles in warmer weather.
*rubber belts are stiffer and offer higher drag.
*rubber tires are stiffer and offer greater rolling-resistance.
*air density is higher,increasing aerodynamic drag.(16% between 70-degrees F and 0-degrees F,and 7% mpg loss alone!)
*engines,when shut off,will lose more heat between restarts.
*you may be operating more accessories (heater blower) and lights (daylight visibility) which will load the alternator.
It's a real can of worms!