Hello,
I live in Northern Maine, and lately in the mornings it is anywhere from 10*F all the way down to -15*F. Before school, I usually start my 850 Turbo about 10 minutes before I leave. I hear this is good to get the oil warm and in a state to move through the engine, but I also hear that idling a car too long can cause unnessisary gas deposits in the engine. I agree with both because I wouldn't leave my car on for 30 minutes, but I wouldn't start it and go right away, unless I really took it easy for a while.

What IS too long for idle?
What do you guys do in cold weather?

-Thanks

 

Hi Keith,

This is my personal opinion and others would know some things I don't so please note that.

I warm up the engine somewhere between 3 minutes and 5 minutes before driving away. I used to idle longer but decided it was excessive. But this is for 850 turbo only, as the cold-start fast idle on 850 seems to have very short duration, not even 1 minute. On Japanese NA cars it seems to take as much as 10 minutes for the engine to come down to 800 plus minus RPM (normal idle speed) in freezing weather.

The pros of warm upare that it is easy on the engine in freezing cold weather, as it is running with no load, and the oil is rather viscous and may not provide sufficient lubrication if driven hard. The cons are that the oil may get diluted a bit (even though this is probably negligiblefor modern oil), as cold-start idle runs on rich mixture commanded by the ECU. It also uses unnecessary fuel.

So, after 3-5 minutes of warm up, I start driving easy to warm up other parts such as the tranny, steering, tyres, brakes, suspension, etc... I do this for about 10-15 minutes and then drive normally. Many owners manuals seem to state that one minute of warm up is sufficient and then you can start driving easy.However I noticed that 85% or more people don't warm up; they start and go zipping. It may not hurt anything on modern cars, but I myself still take time for warm up. BTW, I lived in Vermont for 5.5 years and I know how winter is like up there[X(].

Also, for turbo engines in hot climate, I let the engine idle somewhere between a minuteand 3 minutes as a cool down for the turbocharger. The owner's manual states 1 minute would suffice.

For extreme climates such as New England's, you may benefit by using full synthetic oil. Synthetic blend oils do not seem worth the money, so even though I used to use them, I will switch to full synthetic when I come back to the States and buy a car. In general, SAE 10W-30/-40 is recommended for turbo engines, but if your driving consists of short trips in cold weather, you may want to try synthetic 5W-20 or 5W-30.

Carbureted engines still seem to exhibit a bit of difficulty infreezing weather but this does not apply forfuel injectedengines.

ADDITION:
Excessive idle & slow driving keep the operating temp a bit lower, which used to cause carbon build up on some engines with conventional spark plugs. This would not happen often with today's fuel injected engines, especially those with platinum/iridium plugs, as they are designedto self-clean. But even with conventional plugs & slow driving, one can rev the engine once a while to keep the firing tips clean. I myself like platinums regardless of facts and usually don't gap or re-gap like I do with conventional plugs.

Well, time for others to provide different perspective.


JPN

 

I'm right in line with JPN. 3-5 minutes for me, maybe a little longer if I can spare it. Usually, when it's that cold outside, there's frost on the windows, so I start the car, then scrape the windows. Usually by the time I'm done, the car is starting to warm up. If the idle hasn't fallen, I may wait a bit longer. Then, like JPN, I drive away slowly and try to take it easy until I see the temp guage begin to rise to normal operating temp. It seems on the Volvo and our Subaru, it takes quite a while for the temp guage to rise. If I waited for it every time, I'd have to get up 40 minutes earlier. haha

 

Holy sh#t, That is what you get when you ask an aircraft mechanic a regular question. {;~) Don't askhim a high altitude fuel/air mixture question, the forum doesn't have enough hard drive space. LOL
(Great answer by the way JPN,I admire your attention)

I like to warm it enough for the heater to work, and if I don't have time, I drive real easy until it does.

If you would like more info read on: http://ask.metafilter.com/30641/Shou...before-I-drive

 

!


JPN

 

I warm mine up about 30 seconds, if that. I know I should do more, but I don't.

 

Then you should give me one of your R's... I'll take proper care of it! [8D]

 

Which one you want?

I do let them warm up a little longer when it real cold like it has been lately, but not more than a minute. What's tech's opinion on this? I know all my cars run fine and don't use any oil. I do drive them easy until they warm up, but I can not stand to just sit in the garage with the engine running. Oh yeah my cars are all kept in the garage every night.

 

As far as im concerned once the car comes off of high idle which is less than 1 minutes you are fine.
Everything is oiling in the motor. All is good.

 

I feel much better now. Mine goes off high idle pretty fast and I let it sit for a while after that. Then I figure the backing out of the garage and down the driveway is kind of a warm up too.

 

With all my vehicles, I wait for the idle to drop to normal rpm's and I'm off.
It doesn't matter what the ambienttemperature is.

I will say that for the first mile or two I don't push the car hard. I've never had a problem.

 

I agree with what has been said. Idling for 3-5 minutes tops if it really cold out. With me, My car is in a garage where it is 20* warmer than outside. As soon as it's off high idle I pull out. Take another minute to close the garage and get out of the driveway. Then it's a 5 minute drive at 30mph to the main road. I will be switching to full synthetic at the 7500 mile service. And the cool down is very important! Longer in hot weather. Tom

 

I let the service light go off (2 minutes?) and I'm usually off.

Only when it's cold as hell though (like below 10 degrees). My transmission seems to act funny when the oil pressure isn't built up and circulating so I for sure warm it up.