Do cars really need to warm up first?

[JordanAndrew]

Just an article from Yahoo.




Winter driving tips - warming up the car
- Jeff Voth, Yahoo! Canada Autos
Those of us who live in a four-season climate are used to the idea of allowing our vehicles to warm up on a cold winter's day. But with the technology in today's automobiles, is this still something we should be doing? The simple answer is no. For the most part, letting your vehicle idle for long periods of time in the cold is not only bad for the environment, but can cause serious damage to your engine and emission system.

In the past, most vehicles employed a carburetor to deliver fuel to the engine. Today, almost all cars, trucks and SUVs on the road use some form of electronic fuel injection. In a cold engine, the computer management system tells the fuel injectors to stay open longer allowing more fuel to flow into the engine in part to keep the engine running cool. Trying to warm up the engine at slightly above idle speed is actually doing the reverse and inviting additional problems.

Cold engines produce a much higher level of unburned hydrocarbons as fuel needs heat to burn efficiently. Even the best catalytic converter is unable to process 100 per cent while running at maximum temperature, so allowing the engine to idle for extended periods of time can start to clog the system.

In addition, spark plugs may also become plugged or dirty due to inefficient fuel burning. Older vehicles required regular maintenance, calling for spark plugs to be changed every 30,000 km. Today, almost all engines employ an electronic ignition system that requires spark plugs to be changed at intervals in the range of 100,000 km. An engine at idle for extensive periods of time could dramatically shorten the life of your plugs, causing you to spend hard-earned money on unnecessary service and maintenance.

A better approach is to start your vehicle and let it run for up to one minute before driving away. This will allow fluids to begin flowing through the engine and then warm up to efficient temperatures under normal driving conditions.

Should the temperature outside dip below freezing, allow a maximum of four to five minutes of idle time before driving away. This should be just enough time to clean off any snow or ice that may have accumulated on the windows. While you may not be warm as toast on the way into work or school, you will benefit by saving money at the pump and garage and by driving a vehicle that runs cleaner and more efficient for many years to come.



http://ca.autos.yahoo.com/p/2052/winter-driving-tipswarming-up-the-car

[max_boost]

When it's really cold, 5 minutes and off I go.

[natejj]

Come join me in Yellowknife when its -45 and tell me not to warm up my car for 20 minutes....

[Cos]

Yes you need to warm up a car. If only to allow the oil pressure to drop and the oil to thin a bit.

[wintonyk]

i usually will give 1 or 2 minutes. Enough time to brush off the snow, run back in the house grab my gear than i am off. I don't let rpm go above 3000 until i am at normal temp though.

[sr20s14zenki]

10 minute warmups, fuck the environment

[ExtraSlow]

fuel is cheap, burn lots.

[JordanAndrew]

I usually just turn on the car, brush off the snow and I'm ready to go. Although when we do get around -25 or lower, I do warm up the car an extra minute or two. I'm the same with wintonyk though, I don't drive above 3,000RPM until it's fully warmed up.

[benyl]

haha.

Even on the coldest -35 day, I start and wait for the idle to drop (which is usually 30-45 seconds) and then drive off.

Heated seats FTW.

[Muji]

If my car is plugged in I give it a minute and drive off, keeping the RPM below 3K. Not plugged in and as cold as today, I let it idle for a few minutes. If I had heated seats, the time would be less I would think. I used to think a heated steering wheel was stupid, coming around to the idea these days.

[Supa Dexta]

I sleep in my truck some nights, I'll let it idle all night... :lol

[J-hop]

Originally posted by JordanAndrew
I usually just turn on the car, brush off the snow and I'm ready to go. Although when we do get around -25 or lower, I do warm up the car an extra minute or two. I'm the same with wintonyk though, I don't drive above 3,000RPM until it's fully warmed up.

x3, you actually don't want to let an engine sit their idling for long. Engine wear is the highest when the engine is cold. With some engines it could take 30+ mins of idling for the engine to reach op temp.

I read an article a while ago that stated you should let it idle only for a few mins and then drive it gently, this will help the engine reach op temp quicker and keep it out of the "wear zone". Also remember at idle you don't have much oil pressure and the old is thick (when cold), thick oil+low pressure = bad lubrication.

[SCHIDER23]

10 min max for me if I left the car I'm taking to work outside, usually i don't have much time to wait around lol, yea I like to squeeze every second of sleep, 30 to 40 sec if the car was in the garage.

[luxor]

Originally posted by J-hop

Engine wear is the highest when the engine is cold.

FALSE information! Don't listen to this guy.

Engine wear is the highest at COLD START before the oil can reach the cylinder walls. BIG difference there man.

Originally posted by J-hop

Also remember at idle you don't have much oil pressure and the old is thick (when cold), thick oil+low pressure = bad lubrication.

Wrong again. Oil pressure when cold is actually much higher than your oil pressure at operating temperature. Please also read up on oil viscosity ratings before you claim oil is thick when cold, it's actually quite the opposite. Hint: 5W-30 oil is thinner when cold than at operating temperature.

[n1zm0]

Originally posted by luxor
Wrong again. Oil pressure when cold is actually much higher than your oil pressure at operating temperature. .

we had a rash of newbie pilots whining about high oil px indication snags this winter, those were all of who'm didnt let the engine warm up and shut it down within 30 secs of start up, ridiculars amount of paperwork to sign all due to lack of knowledge..

i want some of whatever J-hop is smoking

edit: but oil is not thinner in the cold, think about it, what happens to any syrup type liquid in the cold, take a jar and put molasses or honey in it, then put it outside overnight in -15 or colder.

in the high arctic, one of my bosses has pictures of him hanging on a DC-3's prop off the ground, the oil was pretty much a block of ice you couldn't even budge it.

[CapnCrunch]

Originally posted by luxor


Please also read up on oil viscosity ratings before you claim oil is thick when cold, it's actually quite the opposite. Hint: 5W-30 oil is thinner when cold than at operating temperature.

I think you need to do some reading. You can't actually be that clueless?

[Abeo]

Originally posted by luxor

Wrong again. Oil pressure when cold is actually much higher than your oil pressure at operating temperature. Please also read up on oil viscosity ratings before you claim oil is thick when cold, it's actually quite the opposite. Hint: 5W-30 oil is thinner when cold than at operating temperature.

Oil does NOT become thinner as it gets colder. Multi-grade oil viscosity does not decrease as the temps go down, rather when the oil is cold it has the viscosity of a straight lighter grade oil (ie: 5W oil @ 0 deg C), and when its up to temp it has the viscosity of a heavier oil (ie: 30W oil @ 70 deg C). Multi-grade oil is thicker when cold, and thinner when hot, full stop.

[kvg]

Originally posted by Cos
Yes you need to warm up a car. If only to allow the oil pressure to drop and the oil to thin a bit.

Thats why I warm my car

[THEMONK]

Because I HATE getting into and driving cold cars, Kelowna here I come.

[Twin_Cam_Turbo]

Originally posted by luxor


FALSE information! Don't listen to this guy.

Engine wear is the highest at COLD START before the oil can reach the cylinder walls. BIG difference there man.



Wrong again. Oil pressure when cold is actually much higher than your oil pressure at operating temperature. Please also read up on oil viscosity ratings before you claim oil is thick when cold, it's actually quite the opposite. Hint: 5W-30 oil is thinner when cold than at operating temperature.

Yes its highest at cold start followed secondly by the engine not being up to operating temperature. And im fairly certain 5W-30 oil is not thinner when its -30 then when its at operating temperature...

Personally if its not below -20 I let the car idle for about 15 seconds then drive gently with lower rpms until it is fully up to operating temperature. The other thing I try to do each drive is open the engine up fully when its warmed up all the way each drive.