pros vs cons of warming up the car on a cold winter morning?

[gmcjohn]

Warm your truck with pride and a smile and look at the bright side I know my remote start shuts down at 24 min. As for global warming, the only hot air is from the dumb ***** in Washington. They screwed up the HVAC/R industry stole money with BS rules. Whats next "farting"

Funny that you mention that.. I heard that there are many environmentalists that point to methane (produced by the ***** matter of livestock) as a big cause of global warming. You know the same ones who are vegetarians and involved with peta are saying we need to kill more animals? damn ******.

 

[gtbigup01]

Total waste of gas, 30 seconds to a minute is all thats needed to get your oil circulating. Xsmn will not warm up until you start driving. IMO no harm done aside from burning gas just sitting. With the gas mileage we get, I would assume you'd rather be driving to burn your gas.

 

[rigo_jones]

With the gas mileage we get, I would assume you'd rather be driving to burn your gas.

uhmmmm... i wouldn't.....

 

[Eagle]

Not needed.

It is the slowest way to warm it up.

What I do is go out fire it up IF IT IS OUTSIDE THE GARAGE, turn on the seat heaters then come back in, make sure my son has his back pack etc, then we go out to the truck, get in, and drive away. On really cold mornings, I stay in tow mode for the first couple of blocks (keeps rpms up in the midrange instead of at 1500, turns off all the electronic slippage) and usually am warm enough to start getting heat (1/4 gauge) when I arrive at his school.

If it is in the garage, those 2-3 minutes are consumed by getting the Tahoe out of the garage, (open door, back out, unfold mirrors, close garage, get son in car, drive away.) And then I drive away at modest throttle inputs and rpm until warmed up.

 

[gtbigup01]

uhmmmm... i wouldn't.....

So you'd rather sit in ur driveway burning gas instead of enjoying your ride, even if it's just back and forth to work? Ok then, more power to you

 

[TunasTwins]

Just to clarify, when the engine is cold, more fuel is injected into the combustion chamber as the fuel can not completely atomize. This extra fuel is injected to ensure enough fuel will be burnt to create the required amount of combustion chamber pressure required to make the engine run, smoothly.
The PCM will command a richer mixture until the defined CLOSED LOOP temperature is met. Once the vehicle hits this defined temp, closed loop will begin and the PCM will adjust injector pulse width based on O2 sensor feedback to achieve 14.68 air/fuel ratio, which, is best for emissions..... Some of you may have experienced your vehicle runs great until it warms up and then it runs like crap-thats a bad O2 sensor most likely. I think everyone has hit valid points here. So....there are different things to consider: comfort-let her warm up; gas mileage-you're getting ZERO when its idling; wear and tear- 0-1 minute idle warm up and then drive like a grandma until you hit closed loop.
Heres some examples of what the PCM is commanding. This was from a 96 LT4 Vette.

 

[El Capitan]

LOL, that is super funny, if i lived somewhere like florida I would never have even thought to "warm up my vehicle"

---------- Post added at 10:48 AM ---------- Previous post was at 10:45 AM ----------



that is part of the info i read online and wasnt sure how valid it was, i didnt want to say anything about it and see if it was brought up here. Ill see if i can find the article again and post it to see what you all think

---------- Post added at 10:50 AM ---------- Previous post was at 10:48 AM ----------

heres the article I read that made me question running my tahoe for 15 minutes every morning:

Although you might think it’s easier on your car to let it sit and gently warm up, doing so is a bad idea for a number of reasons. Most importantly, it does indeed waste gas.

The vast majority of cars on the road today use electronic fuel injection. When your car’s engine is cold, the computer tells the fuel injectors to stay open longer, allowing more fuel into the engine to help it run cold. As the engine warms up, the injectors let in less fuel and everything returns to normal, so to speak.

The problem is, letting your car sit and idle is the slowest way to bring it up to operating temperature because it’s generally sitting in your drive at just above idle speed. And this method to warm up also invites other problems. Remember that modern cars are equipped with a multitude of devices to help them run clean, including a catalytic converter (sometimes three of them), a device in the exhaust system that works to burn off unburned hydrocarbons in the exhaust stream. A cold engine emits a far higher percentage of unburned hydrocarbons than a warm engine. Unfortunately, the average catalytic converter can’t process 100 percent of unburned hydrocarbons even in the best of times. Importantly, the catalytic converter needs high exhaust temperatures to work properly. Throw in a cold engine emitting a high percentage of unburned hydrocarbons, repeat several hundred times, and you can end up with what’s called a “plugged” converter. In a nutshell, the converter becomes overwhelmed and literally ceases to function. This won’t happen all at once but over time, the end effect is the same: poor mileage and significantly dirtier exhaust.

The best bet? Even when it’s 10 degrees F outside, start your car, let it run for 30 to 60 seconds to get all the fluids moving, then drive off gently. Your engine will warm up faster, your exhaust system will get up to temperature faster so the catalytic converter can do its thing, and you’ll use less fuel. Which is what you wanted all along anyhow, right?

If it's below zero outside, it would be a good idea to give the engine five minutes or a little less before you drive off into the frozen wilderness!

— Richard Backus, editor in chief, Gas Engine and Motorcycle Classics magazines

I really don't think he has any idea what exactly he's talking about. Well, moreso, why it does what he is talking about.

Engines will naturally run leaner in colder environments. Colder air is denser air. This leans your car out, which the computer will automatically adjust for(add/pull fuel, advance/retard timing, so on..) it will add fuel to basically put the air/fuel back where it is commanded to be.

They do NOT richen themselves up to warm up faster though. Most fuel injected cars will automatically increase the idle upon startup, until it is warm.
When you add MORE fuel, it actually has cooling properties and makes for very slightly cooler combustion temperatures. so: A car running rich will have a cooler combustion temperature. That's where most of the heat comes from on your motor; combustion heat. The other portion is from the friction of moving parts.

So say on a given 60* day your car is running a 13/1 Air fuel ratio. ON a thirty degree day, your car may WANT to run a 13.4/1 air-fuel(leaner). your car will add fuel and timing to make itself run the commanded 13/1 ratio(it will not richen itself past the commanded A/f), and the added/pulled timing will keep it from preigniting, detonation, knocking/pinging. The same amount of air is going inside, it's just denser therefore there is basically more USABLE air per cubic foot. the engine will add fuel for that extra dense air coming in.

Now if you just got bored and decided to say...add fuel for no reason via a tuner. A. it will richen it up past the commanded A/F and B. it will lower combustion temperatures slightly.
Some tuners will actually add fuel to richen it up just a little to prevent Short-term knock, which can allow them to tweak the timing just a little further(so they can tweak the extra power out of the motor.) Too much timing, and detonation can become an issue. too little can have adverse effects as well. The extra fuel helps cool things down and prevent pinging aswell.


Just trying to clear the air that the added fuel upon startup in cold weather is NOT to warm the engine up faster. It's to compensate for the dense air.

 

[Eagle]

no, he's right.
They do command more fuel (and a target ration OTHER than 13:1) under cold engine temps.

This is because it is LESS efficient when cold, as the tolerances are greater and counter intuitively, so are temps. Stoich has to do with EMISSIONS not power. Power is about 12:1.

remember, we are talking about engine temps. NOT air /external temps. What you are talking about is barometric compensation which happens constantly, we are talking about Open loop warm up, which only happens when the coolant temp is under 90C

Adding fuel PAST peak power decreases temps (which is why you see some turbo cars with 11:1 or 10.5:1 under boost and high rpm) due to heat absorption by the unburned fuel. Adding fuel up to ~12:1? Increases combustion temps.

with the prevalance of front widebands you can actually run closed loop (& non 14.7) under non steady state conditions. Otherwise the only time you are using the o2 sensor is under steady state (cruise).

 

[puckhead]

I have been letting mine warm up between 10-15 minutes. mornings are usually below 0 here. Im gonna try this 5 minute tops thing and see how it does. I burn alot more gas in the winter so anythings worth a shot for me

 

[JennaBear]

I don't let mine sit in the driveway to warm up, as the transmission fluid isn't getting to the gears. Rather, I don't go above 30MPH until I see the temp at a decent level.

 

[Anthony]

I don't let mine sit in the driveway to warm up, as the transmission fluid isn't getting to the gears. Rather, I don't go above 30MPH until I see the temp at a decent level.

Thanks for the tip

 

[vatahoelt]

not sure how valid it is, but i also heard just letting it sit there idling will increase carbon deposits on the pistons.

 

[puckhead]

-18 here this morning. Let is sit for 3 min. or so and then drove off slow. Only "bad" things i noticed was a harder first shift and something in my engine squeals pretty good every time I start it up. otherwise. 3 min worked pretty well

 

[NOPROBROBB]

I ve been doing 5 minutes and using extra caution til it gets warm. Paying close attention to my driving this last week has definately made me more aware of my driving tendencies(good and bad)

 

[badtothe bone]

I'm sitting here, wondering how to make a comment without getting into a pissing contest.

Back in the day, I was sent to school to work on Allison transmissions for the coal mining operator I worked for. Some of the transmissions inside of some bulldozers and loaders were so large that you could stand up inside of them.

Strip job equipment required about a 15 to 30 minute warm up before they were up to operating temperatures.

It is harder on both the engine and the transmission - to just start it up and throw it in gear and drive away. The people who irritates me the most is the idiots who jumps into a cold car and then drives like my grandma for the first 5 miles until it gets warm inside. You can hear me yelling for a country mile for them to shit or get off the pot. Those idiots drives me crazy.

Wear - is worse on a cold engine, that is just thrown into gear and driven off then it is on a engine that has been properly warmed up. Even the Nascar guys warms up their engines before they start a race.

My dirt track car, we put it up on jack stands and even warm up the transmission and the rear gear by running the engine about 2000 Rpm's for about 5 minutes before a race.

If you look in the DIC on the older vehicles such as my old '02 Avalanche you will see a engine hours meter. The oil change is determined by both the engine hours and the miles driven. Most times 3,000 miles works out to be just about right.

Most damage done to the cats are by the additives poured into the gas tank by people wanting to improve performance or clean dirty fuel injectors.

Early style 02 sensors were know to fail somewhere around about 75 - 90,000 miles. Newer style sensors - I have seen some that went 300,000 miles with no issues. The old 4 wire with the heaters built into them were the worst.

Different parts of the country requires different driving styles and different approaches as to how long and if to warm up before driving.
Cold rust belt states like New York, Pennsylvania, Ohio, the New England States - I would say yes. California or Texas or Florida I would say no.

---------- Post added at 11:05 AM ---------- Previous post was at 10:51 AM ----------

When you warm the engine, you also warm up the fluids in the automatic transmission - which lubricates the parts and makes them last longer.

The cooler built in the tank of the radiator reservoir not only cools the fluids when they get hot - to keep them at or about the same temperature as the engine coolant, but also warms the fluids on cold mornings to get them up to operating temperatures faster.

The only time the transmission makes it's own heat is when you put a load against it - like a 7,000 lbs trailer. Even then, all you should have is about 15 more degrees then the coolant temperature. If the transmission gets any hotter than that, you need a transmission cooler.

Warming up your engine -- with ice / frost on the windows is just a good idea in my part of the country, because it is safer - if you are driving down the road with a clear field of view then to be looking out a little hole scrapped in one part of the windshield and windows like some people does.

The Defroster slot on the new Avalanche we just bought is inadequate to properly defrost the entire windshield, and when it is cold outside and you are traveling down the road, you can drive 100 miles and the outer edges of the windshield will not melt when it is cold outside. The air just doesn't travel far enough from the port to reach the outer edges of the windshield and you are better off to use the heat output of the heater to warm the cab then to try to use it to defrost the windshield.

I highly doubt if a Tahoe or Suburban or Silverado is going to have any different of a style of dashboard then the Avalanche.

So just looking at the one aspect of performance is not looking at the big picture when it comes to warming up your engine.

My question is - how much is your life worth? If you get in a crash and end up partially disabled like I am from a automobile accident 12 years ago, how will you support yourself or your family if you get seriously injured?

Me personally, I have no money coming in and the $100,000 that the insurance company gave me for a lifetime of pain and suffering is slowly being ate up by inflation and taking care of my day to day needs. Most people would go out and buy a new truck and a Harley and some other junk and in 2 years would be just as broke as before their accident and would expect the government to take care of them the rest of their lives.

My accident occurred in the rain where a tractor and trailer hit my car from behind. I was on a back country road and the driver had a lot of fog on his windshield because he and his partner was working out in the rain and then jumped into his nice warm truck and the windows fogged up. If it was on ice or snow, I might not be here today.

 

[vatahoelt]

I'm sitting here, wondering how to make a comment without getting into a pissing contest.

Back in the day, I was sent to school to work on Allison transmissions for the coal mining operator I worked for. Some of the transmissions inside of some bulldozers and loaders were so large that you could stand up inside of them.

Strip job equipment required about a 15 to 30 minute warm up before they were up to operating temperatures.

It is harder on both the engine and the transmission - to just start it up and throw it in gear and drive away. The people who irritates me the most is the idiots who jumps into a cold car and then drives like my grandma for the first 5 miles until it gets warm inside. You can hear me yelling for a country mile for them to shit or get off the pot. Those idiots drives me crazy.

Wear - is worse on a cold engine, that is just thrown into gear and driven off then it is on a engine that has been properly warmed up. Even the Nascar guys warms up their engines before they start a race.

My dirt track car, we put it up on jack stands and even warm up the transmission and the rear gear by running the engine about 2000 Rpm's for about 5 minutes before a race.

If you look in the DIC on the older vehicles such as my old '02 Avalanche you will see a engine hours meter. The oil change is determined by both the engine hours and the miles driven. Most times 3,000 miles works out to be just about right.

Most damage done to the cats are by the additives poured into the gas tank by people wanting to improve performance or clean dirty fuel injectors.

Early style 02 sensors were know to fail somewhere around about 75 - 90,000 miles. Newer style sensors - I have seen some that went 300,000 miles with no issues. The old 4 wire with the heaters built into them were the worst.

Different parts of the country requires different driving styles and different approaches as to how long and if to warm up before driving.
Cold rust belt states like New York, Pennsylvania, Ohio, the New England States - I would say yes. California or Texas or Florida I would say no.

---------- Post added at 11:05 AM ---------- Previous post was at 10:51 AM ----------

When you warm the engine, you also warm up the fluids in the automatic transmission - which lubricates the parts and makes them last longer.

The cooler built in the tank of the radiator reservoir not only cools the fluids when they get hot - to keep them at or about the same temperature as the engine coolant, but also warms the fluids on cold mornings to get them up to operating temperatures faster.

The only time the transmission makes it's own heat is when you put a load against it - like a 7,000 lbs trailer. Even then, all you should have is about 15 more degrees then the coolant temperature. If the transmission gets any hotter than that, you need a transmission cooler.

Warming up your engine -- with ice / frost on the windows is just a good idea in my part of the country, because it is safer - if you are driving down the road with a clear field of view then to be looking out a little hole scrapped in one part of the windshield and windows like some people does.

The Defroster slot on the new Avalanche we just bought is inadequate to properly defrost the entire windshield, and when it is cold outside and you are traveling down the road, you can drive 100 miles and the outer edges of the windshield will not melt when it is cold outside. The air just doesn't travel far enough from the port to reach the outer edges of the windshield and you are better off to use the heat output of the heater to warm the cab then to try to use it to defrost the windshield.

I highly doubt if a Tahoe or Suburban or Silverado is going to have any different of a style of dashboard then the Avalanche.

So just looking at the one aspect of performance is not looking at the big picture when it comes to warming up your engine.

My question is - how much is your life worth? If you get in a crash and end up partially disabled like I am from a automobile accident 12 years ago, how will you support yourself or your family if you get seriously injured?

Me personally, I have no money coming in and the $100,000 that the insurance company gave me for a lifetime of pain and suffering is slowly being ate up by inflation and taking care of my day to day needs. Most people would go out and buy a new truck and a Harley and some other junk and in 2 years would be just as broke as before their accident and would expect the government to take care of them the rest of their lives.

My accident occurred in the rain where a tractor and trailer hit my car from behind. I was on a back country road and the driver had a lot of fog on his windshield because he and his partner was working out in the rain and then jumped into his nice warm truck and the windows fogged up. If it was on ice or snow, I might not be here today.

very good post and I'm sorry to hear about your situation.

I think most people in this thread were wondering about the effects of driving on a cold engine vs a warm engine and what is the best way to treat our engines when it is cold outside.

I would seriously hope that people would make sure they could see out the front of their truck before driving off.

 

[Eagle]

bad- heavy equipment is designed differently, is diesel (usually) and has a crap load of lubricant by comparison to a gas engine. Shoot yeah, on a CAT, you warm the sucker up. Completely different beast from a small displacement gas light duty power plant thogh though.

A race engine is also different, nascar warms up their engines. On the other hand nascar engines last mere HOURS. Most of us have more hours use in a week than a nascar engine gets in its life.

F! engines are literally seized solid until the engine reaches operating temps. They obviously get warmed up externally or else you couldn't even turn the engine over.
Here is the warm up sequence on an F1 car...

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I obviously do NOT recommend you spin your engine at 11-18k RPM to warm up, they ARE differnt.

 

[ROBERTOcritser]

whats all this talk about warming up vehicles? I just get in my truck, put my gas pedal to the floor, start it up and throw it in gear and go, never lettin off the throttle. hahaha. that would be wrong on so many levels. seriously though... usually I just let it warm up for my own comfort which usually between 5-15 minutes.

 

[NOPROBROBB]

Badtothe bone, Im sorry as well to hear about the accident, my intentions of starting this post was never to see if i could save money at the pump in exchange of endanger peoples lives but rather to prolong the life of my vehicle if at possible. If its a question between the two i would run my car down to the ground if thats what it took to be safe in the cement jungle.

 

[jESse]

i'm all about letting it warm up first cause half the winter up here is spent in single digit temps or colder at night and letting it warm up for awhile means theres heat when i get in so i'm not as cold and it usually gets all the ice build up and/or frost off the windows so i don't have to spend more time outside scraping it off. what i've found most amusing of this thread is its mostly southern people saying just get in and drive and northern people saying let it warm up. lol. the few extra cents i spend letting it idle are worth it to me to not be frozen or as cold