Do you warm up your car before driving each morning.

[rn79870]

When you first start your car in the morning, do you warm it up, or do you just drive away?

When I do a cold start mine idles at about 2100rpm, and it takes about 30 seconds to drop to 1100. Having the 5AT, I don't like to drop it into reverse with the engine spinning at 2100rpm, so I wait.

Do you wait for the temperature gauge to register, or the rpm to drop, or do you drive away after starting?

[Jacko3]

I always let my cars warm up, so long as they have been left sitting for at least 3 hours. Warm up helps your alternator to recharge your battery, after the car has sat in the driveway, loosing small charges over the night or sitting for a while. Let the car warm up until the RPM drops to 800 RPM or 900 RPM, and when the cars temperature has risen a little. Warm up is a great idea. Warm up also lets the oil to circulate well inside the engine. Warm up allows the car to reach its optimal operating temperature. temperatures above and below optimal are harmful for the longevity of your car.

It is like you waking up from sleep and running a marathon. Of course, you might have other healthy issues as a result of the sudden burst of speed, and probably a heart attack. Unlike a human being, a car will actually drive but over time, you are doing damage to so many internal components of the car.

I have another car with over 200K and it does not burn or short oil . Warming up the car has helped it greatly over time. I hope this helps.

[tollboothwilley]

There was a long discussion about this not too long ago.

Overall verdict seemed to be that most people warm them up for 30 sec - 1 min. Enough to let the oil circulate through the engine. Actually was stated (in the owners manual i believe) that warming up all the way is not recommended. Others sited references explaining that with new cars it is merely a waste of gas.

Living in cold weather, I am very easy on the gas until the engine is at full temp. High RPMs when the engine is cold can be very detrimental.

[D1SR240]

I remember reading about this on this forum, but I could not find the thread. I remember some mechanic posted and said that you should not let your car warm up that long. Only about 30-60 seconds. You should then drive the car, but keep the rpms low until it warms up. I also read this in my Audi A4 owners manual. It said the same exact thing.

[D1SR240]

Looks like you beat me to it tollboothwilley.

[Q45tech]

Cold oil does not lubricate well it must exceed 100-120F before it is very useful - if extremely longevity is desired.

Why engines that daily cold crank don't last 1,000,000 miles without serious ring wear/bearing failure.

A nice 0w30/40 can do wonders if used in winter.

[Tampa G35 Sedan 6MT]

I start it and then I drive. maybe wait 15 sec. I drive about a mile and a half before i get on the interstate. by then the motor is fully warm and ready for 100+ mph lol j/k

DJ

[ArizonaG35]

This time of year (60 degree mornings!) I always let the car warm up in the garage for 30 Sec. or so to let the engine idle down to about 1100 RPM's then drive slowly until it's up to full temp.

In the summer, even when left overnight, my car is "pre-warmed" by the desert heat... Living in the scorching desert, we've become accustomed to the heat, but my garage is another story! 118 Degree outside temps combined with the heat of two cars in my garage will regularly result in a garage tempurature over 145 Degrees! Last summer, my wife and I stored a bunch of water in the garage (in 1Gal. containers) for emergencies... after a couple days, I noticed a pool of water in the garage... The plastic containers had MELTED and exploded from the extreme heat! NOW THAT'S HOT!

[suby01]

i always let the car warm up eighter by turning it on and then going back and driving it.. or always sit in it until the rpms drop to one line above the 1 aka 1100 im guessing. then take off slowly until the temp gauge goes to mid range.. then its 75/77k rpm time

[joe603]

Every day!! When its cold I'll let it idle for a few min. Warmer weather I only wait 30s to a min.

Also, after letting it sit for more than 4 hours, I'll wait 30 seconds before driving.

[johnparkyourcar]

I remember that old thread too, but what's the reason for it? If all that it's doing is wasting gas, I'd rather let my car fully warm up because it'll make me feel better heh... anyone know why you're only supposed to idle for 30 secs~1 min?

[smockers83]

That's about how long it takes for the oil to circulate to all the parts from what I understand.

[telcoman]

When you first start your car in the morning, do you warm it up, or do you just drive away?

When I do a cold start mine idles at about 2100rpm, and it takes about 30 seconds to drop to 1100. Having the 5AT, I don't like to drop it into reverse with the engine spinning at 2100rpm, so I wait.

Do you wait for the temperature gauge to register, or the rpm to drop, or do you drive away after starting?

Usually no because its in the garage all nightYes for a minute or so if its been outside for a few hours and the temperature is below 20F2 minutes if the temp is below zero

Telcoman

[G_whizz]

I wait for the RPM's to drop to about 1k and then

[Focusedintntions]

30 seconds or so...just long enough for me to get on my seat belt, put on my traffic station, put my phone in the cup holder, and take a quick sip of my coffee....

On a side note...you car battery does not recharge while your car is idling....you need to get the rpms up on the the alternator to charge the battery up...usually above 1500-2k rpms

Ever tried to jump a car and have to rev the motor to get the other car to jump?? that's why...not enough juice being put out

[heliochrome85]

thats what i do.

[whtg35]

Let it warm up for 2min....runs like **** if you dont IMO. If im in a huge rush i dont shift passed 2500

[madrigal35]

Always warm your car up! If you have auto start or the time, it is wise to warm up your car for atleast 90 seconds! Never drive it cold and if you do take it slow and easy til the temp rises.

[Jacko3]

Focusedintentions:

Lets begin by saying that a car is a complete system. The natural idle RPM reading when your car is running, is what is technically required to get the alternator to recharge the battery back to its natural energy levels, if the car is driven daily. Your car was designed with daily driving in mind. The longer the car sits, the more juice your car looses, and the higher the RPMS needed to get the juice back to its natural level for the same time frame of idling.

Higher RPMS only increases the rate of charge (charge/time), up to a peak current or amperage. It does not mean you have more charge or if a charge is occuring at all. Far from it.

When a car is is turned off for sometime, lest say- 1 day, your battery looses a very small amount of juice. It looses more juice for each successive day when it is not driven. Thus, a car driven very little will require slightly higher RPMS to increase the rate of charge of the battery by the alternator, for the same idling time. Period! Othersie, if the driver is pateint enough to leave the car idling for much longer, a good laternator will ultimately recharge the battery.

The turn of the magnetic spindle in between the alternator brushes was designed with the diameter and revolution per minute of the pulley in mind. Altering the diameter of the alternator pulley or belt tension, does impact the amount of current going to the battery and the rate of charge for the battery.

As long as the magnetic spindle in the alternator is spinning in between those magnetic brushes in the alternator, as a result of the natural idle RPM of your car, current is being generated and sent to the battery. Higher RPMS only increases the rate of charge, and not the charge itself.

Batteries for home use and batteries for cars, use the same electrochemical process to create their electricity. The difference is in the materials they use to achieve that end. In either case, when you leave either sitting for a while, they will loose some of their electricty.

So, idling your car is a good idea for the engine's internals and for the life of your battery. Because batteries are so cheap to buy and manufacture these days, manufactureres give little thoughts to battery life and costs. Thus, their advice about limited idling time before driving off.

[C-Kwik]

On a side note...you car battery does not recharge while your car is idling....you need to get the rpms up on the the alternator to charge the battery up...usually above 1500-2k rpms

Ever tried to jump a car and have to rev the motor to get the other car to jump?? that's why...not enough juice being put out

Actually it does recharge. But it is unpractical to think that charging a battery is a good reason to let a car idle in the morning. The draw on the battery over a day is minimal. And frankly, the drive to work would be more than adequate to charge the battery.

As for the reason you need to rev up a motor that is trying to jump start another vehicle is because you typically have to overcome not only the starting amps required by the jumpee, but also the elecgtrical load the jumpee's battery is placing by trying to charge itself off the jumper's electrical system. While not recommended in newer cars, disconnecting the battery from the jumpee and attaching the jumper cables to the battery cables directly will allow the car to start without revving it.

[Jacko3]

C-Kwik is correct. The resistance he speaks off, is called electrical resistance. Voltage = Current (I) x Resistance (R). Most elctrical system, so long as they have some wire connection, will present some resistance.

[Sentientbydesign]

30 seconds or so...just long enough for me to get on my seat belt, put on my traffic station, put my phone in the cup holder, and take a quick sip of my coffee....

On a side note...you car battery does not recharge while your car is idling....you need to get the rpms up on the the alternator to charge the battery up...usually above 1500-2k rpms

Ever tried to jump a car and have to rev the motor to get the other car to jump?? that's why...not enough juice being put out

That's not a good example. I tried jumping a caprice with my car and it would because it needed a huge CCA and higher voltage.

You're also trying to supply enough electricity to maintain idle on your car AND turn their starter.

I did a quick search and the results stated that at idle, most alternators supply some recharge power to the battery, though not much.

I personally only warm up my car if it's really cold out or if it's been sitting there for a long time (more than a day). If I do warm it up, I wait for the RPMs to drop (on my I30) or the water temp needle to start registering past the "C".

[C-Kwik]

C-Kwik is correct. The resistance he speaks off, is called electrical resistance. Voltage = Current (I) x Resistance (R). Most elctrical system, so long as they have some wire connection, will present some resistance.

Sorry, but no. The resistance is not the factor that keeps the car from starting. The jumpee car's battery and starter are on a parallel circuit. As such, the total resistance that exists for the entire circuit will always be less than the component that has the least resistance.

1/Rtotal = 1/R1 + 1/R2 + 1/R3 + .... + 1/Rn

The factor here is the current draw. Each component has a certain amount of current draw. When the combined current draw of the components in the jumpee vehicle is greater than the capacity of the jumper vehicle's output, it will not be able to start. By disconnecting the jumpee vehicle's battery, you lower the current draw on the jumper vehicle basically allowing sufficient current to be available to the starter.

The only potential resistive force that might become a factor is in the jumper cables themselves. And given that most people tend to buy or end up with rather cheap jumper cables (read: wiring too small), it may not be surprising to see.

[W661335PF]

When you first start your car in the morning, do you warm it up, or do you just drive away?

When I do a cold start mine idles at about 2100rpm, and it takes about 30 seconds to drop to 1100. Having the 5AT, I don't like to drop it into reverse with the engine spinning at 2100rpm, so I wait.

Do you wait for the temperature gauge to register, or the rpm to drop, or do you drive away after starting?

Geez, you'd think a dissertation was being requested for a simple question...

Yes I warm up my car for about 30 seconds. the greatest damage to an engine occurs at start up, for most of us (except for those who like to rev at extremely high rpm repeatedly), since this is when the least amount of lubrication is coursing thru the system. While a small amount of lubricant coats the chamber and rings, the amount is not enough to fully protect the engine if it's being pushed aggressively. 30-60 seconds allows the oil to circulate thru the system. I don't wait for the temp gauge to register, even in freezing weather (<10 degrees celsius) but will warm it up >60 seconds if the car has been parked for 2-3 hours.

On the other hand, dling an engine is bad in many ways. The fuel is not completely burnt, so it condenses in drops on the cylinder walls. This leads to both extra wear of the cylinder walls (because the fuel washes the lubricating oil off the walls), and unburnt fuel flowing down the walls and contaminating the oil in the sump. Idling also drops the temperature of the spark plugs, leading to dirty plugs, which can worsen your fuel consumption by some 5%.

You might have noticed a vapour coming out of the exhaust of some cars in the early morning. That vapour is not the oil vapour of a worn engine, but the normal water vapour from a cold engine. So the longer you idle the engine, the longer it will take to warm up, and so more water droplets will be deposited inside your exhaust system – making it rust sooner.

A long time of idling means that the engine will produce a lot more unwanted pollutants. For example, modern cars have catalytic converters. When they get to their normal operating temperature (400-800°C, which is a lot hotter than the engine), they convert nasty pollutants into much less nasty chemicals. And you guessed it, the quickest way for catalytic converters to get to their normal operating temperature is by driving, not idling. The longer the time that you idle your engine, the longer that your catalytic converter is too cold to do its job.

Finally, hopefully the emerging electronics debate will not result in a similar scenario we witnessed 1 week ago when several folks were threatened with expulsion from the site.


Modified by W661335PF at 2:49 PM 2/20/2008

[telcoman]

Actually it does recharge. But it is unpractical to think that charging a battery is a good reason to let a car idle in the morning. The draw on the battery over a day is minimal. And frankly, the drive to work would be more than adequate to charge the battery.

As for the reason you need to rev up a motor that is trying to jump start another vehicle is because you typically have to overcome not only the starting amps required by the jumpee, but also the elecgtrical load the jumpee's battery is placing by trying to charge itself off the jumper's electrical system. While not recommended in newer cars, disconnecting the battery from the jumpee and attaching the jumper cables to the battery cables directly will allow the car to start without revving it.

C-Kwik

I believe you are correct. If anyone would care to measure the voltage across their battery terminals prior to starting their car they will see 12.6voltsStart the vehicle and observe the voltage again. If the alternator is functioning correctly you will read 14.4 volts with the engine idling.If one were to insert an amp meter in series, I doubt very much that you would see an increase in charge rate (amps) between idling at 800 to 1000 RPM and the engine at 3000 RPM. The alternator will charge the battery even at idle. In old vehicles that had a generator this was true but not with alternators. The bridge rectifiers in the altenators will supply almost max output even at idle.When using jumper cables the voltage drop caused by the resistance of the cables and the load placed upon the running vehicles alternator is why increasing the engine speed will overcome the resistance and allow the other vehicle to start. Never buy cheap jumper cables. Try to obtain 6 gauge cables.

Telcoman

[Jacko3]

C-Kwik:

If you are right about the parallel arrangement of the circuits, then i would agree completely with your equation. Thus making resistance a less of an issue. The equation you presented is the correct equation for resistance in parallel connections, as opposed to resistance in series which would look like

Rtotal = R1 + R2 + R3 + .... + Rn.

However, according to Ohm's law, Voltage (V) = Current (I) x Resistance (R). Thus, the little resistance, as you have aptly suggested in your equation Rtotal = 1/R1 + 1/R2 + 1/R3 + .... + 1/Rn,

Would infact contribute very little in the Potential differece or Voltage (V) when Current (I) is multiplied by Resistance (R). Thus, the new equation, would be

Voltage (V) = Current (I) (because R, is no more needed, as it contributes very little to the charge or discharge).

So, what really matters as you have rightly said, "The factor here is the current draw" is what we call the electromotive force, which does determine the level of charging or discharge of current.

In essence, you are presenting very important parts and aspects of the overall equation I had earlier presented.

[Sentientbydesign]

I think mine are 4 gauge

[W661335PF]

C-Kwik:

If you are right about the parallel arrangement of the circuits, then i would agree completely with your equation. Thus making resistance a less of an issue. The equation you presented is the correct equation for resistance in parallel connections, as opposed to resistance in series which would look like

Rtotal = R1 + R2 + R3 + .... + Rn.

However, according to Ohm's law, Voltage (V) = Current (I) x Resistance (R). Thus, the little resistance, as you have aptly suggested in your equation Rtotal = 1/R1 + 1/R2 + 1/R3 + .... + 1/Rn,

Would infact contribute very little in the Potential differece or Voltage (V) when Current (I) is multiplied by Resistance (R). Thus, the new equation, would be

Voltage (V) = Current (I) (because R, is no more needed, as it contributes very little to the charge or discharge).

So, what really matters as you have rightly said, "The factor here is the current draw" is what we call the electromotive force, which does determine the level of charging or discharge of current.

In essence, you are presenting very important parts and aspects of the overall equation I had earlier presented.

Fascinating explanations; however, voltage (E) never = current (I) alone, resistance (R) is integral to the equation. And I believe that the more accurate way of representing the equation, for our purposes would be I=E/R.

[Jacko3]

W661335PF:

C-Kwik accurately noted a point. In physics and the sciences, when a factor becomes negligible or infinitessimal, it is removed. In essence, I am saying that Rtotal = 0 or negligible as C-kwik had noted. To that extent, the equation automatically reduces to

Voltage (V) = Current (I)

This does not mean that the equation V = I x R does not hold. It only means that by the assumptions suggested by C-Kwik given the conditions we have both stated, the final equation, for our specific case will ultimately become;

Voltage (V) = Current (I)

In addition, Voltage is typically denoted by V and not E.

And i am not sure what point your are trying to make by stating that

I = E/R.

If you replace the letter E with its proper nomenclature of V, what you have is

I = V/R

If you remove the denominators on all sides, what you then have is

I (Current) x R (resistance) = V (voltage), which is exactly what i had earlier stated in all my comments.

Let me help you a little bit in the mathematics of this matter, by stating some obvious mathematical derivations of this issue:

1. V = I x R

2. V/I = R, as long as I is never equal to zero or infinity

3. V/R = I, as long as R is never equal to zero or infinity

Replace V with your E and you can see that you are saying the same things as I, but using atypical nomenclature.

Voltage is generally represented by V while elctrical energy is typically depicted with E or W. Power is depcted with P. The sciences have specific symbols that most around the world, tend to adhere to. Even more restrictive in nomenclature, if we take a look at it, is the use of the S.I units.

However, it is okay to express liberty in the use of nomenclatures.

[W661335PF]

W661335PF:

C-Kwik accurately noted a point. In physics and the sciences, when a factor becomes negligible or infinitessimal, it is removed. In essence, I am saying that Rtotal = 0 or negligible as C-kwik had noted. To that extent, the equation automatically reduces to

Voltage (V) = Current (I)

This does not mean that the equation V = I x R does not hold. It only means that by the assumptions suggested by C-Kwik given the conditions we have both stated, the final equation, for our specific case will ultimately become;

Voltage (V) = Current (I)

In addition, Voltage is typically denoted by V and not E.

And i am not sure what point your are trying to make by stating that

I = E/R.

If you replace the letter E with its proper nomenclature of V, what you have is

I = V/R

If you remove the denominators on all sides, what you then have is

I (Current) x R (resistance) = V (voltage), which is exactly what i had earlier stated in all my comments.

Let me help you a little bit in the mathematics of this matter, by stating some obvious mathematical derivations of this issue:

1. V = I x R

2. V/I = R, as long as I is never equal to zero or infinity

3. V/R = I, as long as R is never equal to zero or infinity

Replace V with your E and you can see that you are saying the same things as I, but using atypical nomenclature.

Voltage is generally represented by V while elctrical energy is typically depicted with E or W. Power is depcted with P. The sciences have specific symbols that most around the world, tend to adhere to. Even more restrictive in nomenclature, if we take a look at it, is the use of the S.I units.

However, it is okay to express liberty in the use of nomenclatures.

V and E are interchangeable actually. E was used decades ago and has been around much longer. it was recently changed to V.... we're saying much the same thing tho. Thanks for clarification, I wasn't reading the argument carefully.
Modified by W661335PF at 3:18 PM 2/20/2008