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To warm-up or not to warm-up

As I think most people have, I grew up with the understanding that warming up your vehicle before a drive was a good thing. I recently received a newsletter in the mail urging me not to warm-up my vehicle this winter as it is bad for the environment and no good for my engine. I agree with the environmental damage, but is warming-up harmful to my cars engine?

At this time of year we get one post each week minimum on this subject.


  1. Your engine warms up quickest with some load on it, i.e. driving it.
  2. An idling engine runs very ineffienctly and pollutes more than a loaded one. In addition, your are not moving while you’re idling; causing even more waste.
  3. The fuel/air mixture during idling is not the best for maximum engine life; raw gas washes the oil off the cylinder walls.
  4. If you warm up the engine first, than take off fast, you are putting incredible strain on the other components of the car that are still cold. Taking off shortly after starting warms up the whole power train and suspension together.

In spite of the (4) points, you need to idle the car long engough to get the engine oil to circulate to the valve gear on top of the engine. In most of the US, with 5W30 oil this takes no more than 20 seconds or so. If you start the car, belt yourself in, check mirrors, you should be ready to take off gently and when the temperature gage is half way to normal, you can blast off.
In all cases, make sure your windows are clear before taking off.

Happy and GREEN motoring!!

I will add to Doc’s post the importance of warming up your engine long enough to get the defroster to keep the windshield clear once you hit cruising speed. Lately that seems to be my defining criterion.

Since this topic has been extensively covered in many recent threads, you might want to do a search of this site in order to see all of the responses. But, if you want a quick and dirty summary, I will give you one: While warming up your engine will not harm the engine, it definitely harms your wallet and the air that we breathe, and is absolutely unnecessary in modern cars with fuel injection.

If temperatures are sub-freezing, you might want to wait for as long as 30 seconds before driving away–slowly. Driving gently for the first few miles actually warms the engine AND THE TRANSMISSION far more quickly and far more effectively than idling does.

The best source of information on this topic is sitting in your glove compartment, so I would suggest that you take out the Owner’s Manual and read up on this topic, as well as others.

The best bet is to give it say 30 seconds on the very cold mornings and then drive off. Get a mile or two before hitting the highway.

That warms it up fast and without stressing the engine. It also warms up the transmission and power steering fluids as well as the struts and other ssuspension and drive train parts.

So save the environment and you car and don’t idle it to warm it.

Is warming the engine up harmful? Nope. Car engines are designed to run. It will warm up faster if you drive it, and more fuel will be burned when it is cold. Extended idling (taxicabs, police cars, limo’s) might have a problem, but the standard family car will suffer no real problems by a short warm-up. I agree with the other posters . . . start it . . . belt in, check your mirrors, get a good tune on the radio, and drive away slowly and take it easy for the first few miles. Now COOL DOWN of the engine, that’s a whole other story! Will running your engine for a few minutes after you park the car harm your engine? :0) Rocketman

“will running your engine for a few minutes after you park the car harm your engine”. No.

Some turbos require a short cool down time only.

I agree, it won’t actually hurt the engine but it’s also not necessary and it uses extra fuel. The folks that are telling you it will harm the engine are probably just overstating their case.

If you have ice and snow on your car, start the engine and turn on defrosting/deicing equipment and let the engine run while you scrape ice as necessary. Otherwise just start the car, put it in gear and go. Just be gentle until temp gauge starts to move.


Almost all those points are absolutely correct. 20-30 seconds is plenty. Where I was living in North Dakota, with the temps routinely below 0F in the winter, a solid 30 second warm up, and I was off. Driving nicely for a bit until the gauges were moving, and off I went…providing the roadway (and my windows) were clear. Both vehicles are still doing just fine years later.