Turning Off Car Engine Before Warmed?

[SkunkedAgain]

This one has always bugged me, and I haven't had much luck searching online for an answer:

If you start you car on a typical -10 degree day in Minnesota, is it bad for your engine to turn it off a minute or two later, before the vehicle has reached normal operating temperate? Does it matter if the outside temperature is above or below freezing?

Hopefully this invites some informed responses, and not just a bunch of opinions.

[Scott K]

Starting your engine is the worst thing you can do to it, not shutting it off. When you start a cold engine, the oil is thick, it has all drained back to the pan, so the oil isnt where it needs to be to lubricate the engine on start up, and when the temps are below 0, the oil takes a longer time to get to the top of the engine. Once it is started and oil reaches the top of the motor, and the oil is warm, there is minimal wear on the engine. But to answer your question of shutting it off, wouldnt effect things at all. my question to you, why are you starting it, then shutting it off? If you can, avoid starting it when temps are that cold, that would be the best thing to do for it.

[SkunkedAgain]

I'm talking about the short 1 mile drive somewhere.....or starting your truck, remembering that your still wearing your pajamas, so turning off your vehicle so you can get back into the house to put on your work clothes.

So if short trips are only rough on your gas mileage, then great!

[Scott K]

It is just the starting the vehicle that is hard on it.

[Macgyver55]

Repeated or frequent short warming cycles can cause excess moisture (condensation) to accumulate in/on the motor and exhaust system. It also doesnt give the computer time to go into closed loop and start performing necessary functions for proper fuel delivery and the catalytic converters also need time to get up to proper running temp. A full warm up cycle is needed to undo any effects the short cycles may have. Repeated short run times are not the best for long life of components, especially in cold weather .

[jeffreyd]

one rule of thumb is that when a cold engine sits, the oil drains back, it grabs moisture from the air and allows it to enter the oil. so the purpose of warming an engine to operating temp is not only to ensure that oil is up top and you are not doing damage, but to burn off moisture in the oil. the other thing that is hard on them is after a long or hard trip simply to shut it off, i say a minute of idle before shut down is good. if you run a diesel with turbo they recommend 5 min of idle to allow the turbo to spool down and that there is lube in the turbo.

[SkunkedAgain]

So 1 vote for "no problem" and 2 votes for "it can shorten the life of your engine"

[Scott K]

I will have to agree that it does effect exhaust and water may collect in the oil.

[SkunkedAgain]

So driving over to the neighborhood pizza shop every once in a while when it's cold won't hurt it, but doing those short drives on a regular basis would cause problems?

[BobT]

I would agree with MacGyver55. Once in a while isn't going to be anything to sweat over but if for example your job is only a mile away, you might run into condensation issues. From what I've read, this issue can be a problem for anyone that drives less than 10 miles to work. The engine and drive train just don't get up to temp for a long enough time period to evaporate the moisture that has condensed internally. Typical problems include excess moisture in oil and exhaust causing premature exhaust rust through and engine problems with gunk building up internally. More frequent oil changes might be helpful here too.

Nest time you start your car on a cold day, take notice of the amount of water running, and I mean running, out of your tail pipe. This is more prevalent in today's more efficient burning vehicles too than it was years ago. It takes quite a while for that system to get hot enough to prevent the moisture from condensing in the exhaust system.

[SkunkedAgain]

Good point BobT. I live only 3.5 miles from work. In the winter, I take side roads so that my truck gets up to temperature before pulling into the parking ramp. Maybe I need to do a little more sight seeing before pulling in. Maybe I'll actually get warm before getting out of the truck!

[CJH]

Could you maybe idle it for 5 minutes before leaving the house?

[Jeremy airjer W]

I also have a 3.5 mile commute. I'm not worried about it. Even more so since I have at least one commute a week that gets the motor good and hot.

[The_Duckslayer]

I'm talking about the short 1 mile drive somewhere.....or starting your truck, remembering that your still wearing your pajamas, so turning off your vehicle so you can get back into the house to put on your work clothes.

So if short trips are only rough on your gas mileage, then great!

Too funny!!! Unless of course you have actually done that! jus sayin...

Take care and N Joy the Hunt././Jimbo

[shizzy]

I would agree with MacGyver55. Once in a while isn't going to be anything to sweat over but if for example your job is only a mile away, you might run into condensation issues. From what I've read, this issue can be a problem for anyone that drives less than 10 miles to work. The engine and drive train just don't get up to temp for a long enough time period to evaporate the moisture that has condensed internally. Typical problems include excess moisture in oil and exhaust causing premature exhaust rust through and engine problems with gunk building up internally. More frequent oil changes might be helpful here too.

Nest time you start your car on a cold day, take notice of the amount of water running, and I mean running, out of your tail pipe. This is more prevalent in today's more efficient burning vehicles too than it was years ago. It takes quite a while for that system to get hot enough to prevent the moisture from condensing in the exhaust system.

I drive 3 miles to work and stick to the 3k oil change schedule for this reason. I also at least once a week try to go drive somewhere that is at least 10 miles away to make sure the truck gets nice and warm.