Should You Warm Up Your Car Before Driving?

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Originally Posted By: edyvw
My HVAC is ALWAYS on cold! I set it up on cold before I turn off car night before. What that does is that it cuts off secondary radiator, so outside air will not prevent coolant reaching temperature fast because there is a flow of air thru secondary radiator. Keep vent on off or min just to keep windows clear.


I believe you are wrong on this one--mixing valves went away a long time ago. These days the heater core gets full coolant flow always; and instead the mixing valve is actually a flap that allows/disallows airflow over the heater core. I don't know when the changeover was (and of course not everyone did it on the same day).

But I agree with you: turn the fan off, and the car should warm up faster. No airflow over that "radiator". But do try to argue that with SWMBO and see if your logic prevails.
 
Originally Posted By: supton
Originally Posted By: rshaw125
I warm mine up so I can see through the windshield. It's a good idea to have some idea of where other vehicles are.


Get an ice scraper. Takes too long for the engine to warm up on its own.

Also, you should have the other windows defrosted too.
wink.gif



If you're getting fog on the windows, you need to clean the interior windows. Dust and dirt on the inside windows allows them to fog up easily.

I'm near some major highways and I don't really let it warm up. I typically just start the car, put on the seatbelt, adjust the radio and then just take off. I just don't do WOT, but getting on the highway, the car shift through the gears and may do 3-4k rpms within a couple minutes. One car lasted over 200k doing that. Modern fuel injected engines don't need a warm up. I end up getting heat from the car about 5 minutes or so driving normally.
 
Originally Posted By: edyvw
AGAIN? I thought in this digital age this ridiculous myth would die.
OP, you are running PP 5W30 in very, extremely, uber whatever simple engine.
What I do is that I turn on car, by the time I put seat belt on, turn on seat warmers, music, it is like 10 seconds. Then I back up from garage without touching pedal, that is another 30-45 doing it slowly.
My HVAC is ALWAYS on cold! I set it up on cold before I turn off car night before. What that does is that it cuts off secondary radiator, so outside air will not prevent coolant reaching temperature fast because there is a flow of air thru secondary radiator. Keep vent on off or min just to keep windows clear.
Stay up to 2500 rpms. After 5 min slowly start using heat. This method will warm up your car much faster then any idling in drive way.


It feels great to dispel one myth while being a slave to another, doesn't it?
 
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I let it idle for 15-20 seconds max while I put on my seatbelt and change the radio station.

Sometimes I do what I've seen Shannow says he does, turns off overdrive so it doesn't go into top gear for the first couple miles.
 
Letting the engine get legitimately warm probably is an unnecessary hold-over from days when engines wouldn't run right until they were close to operating temp. Now that fuel injection has mostly mitigated that, my opinion is that it's only really beneficial to let things start[/] to get warm inside the engine before taking off. In fact, some engines like my Cruze's 1.4 are so efficient that they'll hardly get warm unless they're under load. Above 45-50 degrees, I just wait for high idle to settle, then am gentle with it (no excessive load or revs over 3 grand) until temp needle reaches its usual resting point. Colder than than that, I'll give it 20 seconds to a couple minutes before driving. If it's a tow vehicle, however, I prefer to let the temp needle start moving before I take off given the extra load.

Almost as religiously as I observe warm up habits, I observe cool down time - the hotter the engine will have been from whatever I was just doing, the longer I make sure it's either idled or run under minimal load before shutting off. That also serves as a time to shut off accessories and appliances to reduce engine and electrical load - maybe part of the reason I replace so few batteries in anything I use regularly.
 
Originally Posted By: Kamele0N
Originally Posted By: Miller88


If it's the Focus or the F350, I will usually wait for it to idle below 1500 before taking off. Both will idle at 2500 when first cold started.


Are focus and F350 ancient carbureted versions with manual choke? Pretty insane rpms for cold idle for car with ECU and injection...


The F350 is a 2001, focus is a 2011. My old 2001 Taurus would do the same thing.

It's ridiculous, but they MUST rev to crazy high RPM when cold for some reason. My taurus, if cold started and put right into drive, would accelerate up to 25 or 30 on its own. The truck and Focus are manual transmission and it's a pain to shift them when cold - as soon as you push the clutch in, they rev right to 2500 again.

All three have been to the dealer for it and it's "normal" apparently. Lights the cat(s) off.
 
Originally Posted By: Wolf359
Originally Posted By: supton
Originally Posted By: rshaw125
I warm mine up so I can see through the windshield. It's a good idea to have some idea of where other vehicles are.


Get an ice scraper. Takes too long for the engine to warm up on its own.

Also, you should have the other windows defrosted too.
wink.gif



If you're getting fog on the windows, you need to clean the interior windows. Dust and dirt on the inside windows allows them to fog up easily.

I'm near some major highways and I don't really let it warm up. I typically just start the car, put on the seatbelt, adjust the radio and then just take off. I just don't do WOT, but getting on the highway, the car shift through the gears and may do 3-4k rpms within a couple minutes. One car lasted over 200k doing that. Modern fuel injected engines don't need a warm up. I end up getting heat from the car about 5 minutes or so driving normally.


That's a good point, although I can get fog with clean windows too. it helps to crack a window, especially if the vehicle takes a while to generate heat.

That said, I've had a number of instances where the windshield would freeze back over, while underway. And I mean the outside of the windshield, not interior. I've puzzled over it for years. Just the other weekend though I was shoveling after a storm, and cleaned off the cars, and scraped the windows. But did not start. As the sun came out I went back to moving snow. Hour later I looked, and the windows were freezing over again! Cold glass pulling moisture out of the warming air, it seemed.

So I've never been against warming up a vehicle; even a hint of heat out of the defroster vent is a godsend to keeping the windshield from fogging and/or frosting (although it doesn't negate the need to scrape ice initially).

Originally Posted By: LeakySeals
Climbing a hill right out of the driveway I will hearing ticking/piston slap noises if I don't wait a couple minutes.


I've noticed a few times my new-to-me Camry will do the same thing (piston slap? rod knock?). Albeit in warmer weather.
frown.gif
I suspect the prior owner may not have been as kind to it as I will be--or maybe it's just the nature of the beast. Hasn't been doing it in this colder weather, ironically, because I tend to let it warm up a bit more before moving.
 
Originally Posted By: Miller88
Originally Posted By: Kamele0N
Originally Posted By: Miller88


If it's the Focus or the F350, I will usually wait for it to idle below 1500 before taking off. Both will idle at 2500 when first cold started.


Are focus and F350 ancient carbureted versions with manual choke? Pretty insane rpms for cold idle for car with ECU and injection...


The F350 is a 2001, focus is a 2011. My old 2001 Taurus would do the same thing.

It's ridiculous, but they MUST rev to crazy high RPM when cold for some reason. My taurus, if cold started and put right into drive, would accelerate up to 25 or 30 on its own. The truck and Focus are manual transmission and it's a pain to shift them when cold - as soon as you push the clutch in, they rev right to 2500 again.

All three have been to the dealer for it and it's "normal" apparently. Lights the cat(s) off.


Higher rpm, heats up faster. More importantly, it probably heats up the catalyst faster. There are cold start limits to be obeyed. Also, I wonder if the higher rpm helps with transmissions: a manual trans will heat up a bit, even in neutral. I could tell in my TDI what a few minutes of idling would for shifting. An automatic is no different, although the pump likely makes far more heat (then again, thin ATF shouldn't need much heating I'd think).
 
I follow my owners manual which says to try to get under way within a minute and not let it idle excessively. It's a small displacement DI engine that needs to be under load which makes sense...but most of the other fuel injected cars I've had in the last 10-15 years say pretty much the same thing - warm up should be done during driving and not idling.

Maybe in that sense you can think of the concept of warming up as a hold over from the past. But, I think it's probably safe to say that depending on the circumstance and the vehicle, the reality might not always match the notion of not letting it idle for a bit. There's probably an ideal answer but not necessarily a right or wrong answer if there are competing needs.
 
Anything more than 30 seconds to a minute is too long. I start my car with remote start as I am walking out the door, open the door, load my bag into the car, and get in. Put it in reverse and go. It takes a minute or so for me to be in reverse. After going, I do keep the car below 3000 rpm until the temperature gauge starts to move. Even then, I try to keep a little lighter on the gas pedal until it is up to normal temp. In my 4 cylinder protege, 3k rpm is more than enough for going from 35-60 at an acceptable rate of speed. Even in my carbureted vehicles, I only let them run for 2 or 3 minutes before I start driving them. 5 minutes if it is cold enough to cause idle troubles or if the car is being picky that day. Anything past that is a waste. Just keep the rpm below half of your redline and you should be happy. This has kept my protege running for over 200k miles trouble free when it comes to engine and transmission.
 
I warm the car until I'm certain the heater can keep the windscreen clear. I'm not moving until I'm certain I can see. Running over a pedestrian or cyclist just because my windows were damp is something I don't want on my conscience, even if they weren't in an area of the road reserved for them.

I have a diesel, they do take longer to warm up, and I can easily be a mile from home before the heater even starts to blow lukewarm air. Or, I let the car run for a minute or 5 in front of the house while I drink my coffee.
 
Originally Posted By: blupupher
I just love all these "keep it under 3000 rpm" lines.
Not everyone drives a small engine vehicle. 3000 rpms in my 5.4 is pretty excessive.

I don't understand the problem. Isn't the whole reason to get 0w and 5w oils to have good cold weather oil flow? Why would you need to wait for the oil to warm up (which will make it thicker) before driving?


Good God... please do some more research on what oil viscosities mean in the real world.

And 3K RPM while cold isn't excessive for your 5.4L. I've put hundreds of thousands of miles on big V8s with my "under 3K cold start" rule with absolutely no engine issues.
 
Some of you change your radio station too much ha

I get in, start, buckle, get phone in holder, plug it in, start Waze and audible/podcast, then get going. When it's zero out, it may sit a little longer or if I have to scrape, but most of the time I scrape and then get in the car. It's 25-30 mph to get out of my neighborhood (1.5miles) then it's a 50mph rural road. I do not go into OD (5th) until the temp gauge moves.

We'll see how long it lasts because y'all aren't going to change how I drive. 130000 miles and counting.
 
Nope. Start my jeep, get phone situated with blue tooth which takes approximately 30 seconds then I baby foot it until it warms up. I do it when it's 80*F out and when it is 0*F out.
 
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I do like to warm up my engine before driving away. The time depends on how long the car has been sitting for and how cold it is outside. My cars have automatic climate control that is almost imperceptible when the engine is cold and will gradually increase the blower fan as heat is available. The heating up the inside isn't the main factor for me to allow the engine to run. On cold morning starts my car will idle at 1200 rpms for a while and so if I chose to put it in gear then it is a much harder engagement. Subsequently this is just adding wear and tear on the motor mounts. The time it takes to get to 1000 rpms or under is the time the car(s) get to "warm up." The actual temperature of the heat is irrelevant to me unless I need the heat to see out of the windows. I like to put my car(s) in gear and have a nice smooth engagement and smooth(er) idle when compared to less than 2 seconds after the engine is started and put into gear. A couple times this last few days though the car required 15 or so minutes to warm the windows so I could see due to the complete sheet of ice on everything (all the windows, hood, doors).

Do I believe allowing XX minutes increases the life span of the engine? My answer is: It depends on how long the engine has been sitting and what the conditions are like. At the very least enough time for the engine oil to get moving to where it needs to be. This is of course subjective and probably falls under a "feel good" kind of judgement. Same as driving habits of the same said conditions. Obviously WOT on a 5 degree cold morning start (car sat for 10-12 hours) is another thing I wouldn't do.

Even the responses I read so far saying they set the radio, put the seat belt on etc are still to me, warming it up. The examples I see often of starting and literally going without so much as 5 seconds would be "not warming it up."
 
I let my trucks warm up if I don't want to be cold. If I'm comfortable, it's time to go. It can take 10 minutes just to get out of the neighborhood, so they are most of the way to warm by the time I get to a main road.
 
Originally Posted By: edyvw
Originally Posted By: blupupher
I just love all these "keep it under 3000 rpm" lines.
Not everyone drives a small engine vehicle. 3000 rpms in my 5.4 is pretty excessive.

I don't understand the problem. Isn't the whole reason to get 0w and 5w oils to have good cold weather oil flow? Why would you need to wait for the oil to warm up (which will make it thicker) before driving?
...

I just cannot believe I read this.



From they way I understand it, a 5w-30 oil starts out "thin" when it is cold and as it warms up and approaches operating temp, it thickens to a 30 wt oil. Once you go above 100°C it will start to thin out again.

Or have I misunderstood this all the time. I know 5w is the winter rating, but above is how I understood it works.
 
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