Hey all.

So it's been getting colder here in Texas and I'm wondering if there's any real technical need to warm my car up before driving it normally. I've always heard it's "bad for your car" to just start it up and drive it in the cold as you might do when it's hot. But for modern, well-maintained, fuel-injected cars with fully-synthetic motor oil, is this still true? I'm particularly talking about temps in the 20s F and above (not the ridiculous sub-arctic temps they're getting in the Midwest right now).

I just want to make sure that sitting in my car for 10 minutes picking my nose while the engine warms up is time well spent--or if that's just an old wives tale and really unwarranted for modern vehicles.

Thanks.

 

At those temperatures I wouldn't let it warm up longer than 30 seconds... If I let it warm up at all. Typically when they tell you to warm up your engine is when it gets cold for winter, northern states and Canada.

 

I usually try to give my car at least a minute or two in the morning before it sees any load. Although I must admit there's times where I fire it up in the cold of the morning and throw that sucker into gear before the idle even comes down and be on my way.

You don't have to get it up to temperature, just give it a couple minutes to get the oil warm.

 

A few seconds of warm up is all you ever need. The engine will warm up faster if you drive it than if you leave it idling.

 

I agree, at your temperature, you need little warm up. 30 seconds should be fine. When it gets down to zero, I am still at a 30 second warm up. In addition, my first mile of driving is in town, so I am still at slow speeds, 20-25 mph. At -20, I warm up 45-60 seconds. Today at -34 I let it run till it brought the fast idle down about 50% which took just under 2 minutes. I run my engines 200,000 miles and more. Just keep good oil in it and change when needed.

 

One more thing. Don't bother warming it up terribly much, but don't start up and pull onto the street and wack it wide open. Take it easy until she's warm.

 

Sounds like I've been wasting my time in the driveway. Thanks everyone!

 

Living in Illinois I always let mine run a few minutes. Not to fully warm up just to let the oil get warm and moving good before putting a load on it.

 

Not to mention idle = zero mph = very bad MPG.
If it's below freezing, yes I idle it for 3 minutes otherwise no more than a minute either way smooth acceleration until it's warmed up which doesn't take long.

 

The point of "warming up the engine" is to get the oil that's been dripping into the pan all night to move and lubricate the engine before driving. It's not to actually warm the engine.
Getting in and going is technically running it dry. You need to lubricate before going anywhere.
With that in mind, I let it run for ~30 seconds minimum and up to 3 minutes in our "sub-arctic temps". I'm in the midwest. -37F windchills are nasty.

 

No, because you've still got plenty of oil film clinging to everything for the second that it takes for new oil to arrive. The oil that's been dripping into the pan all night has been sitting in useless places, like the heads, the walls of the block, and the lifter valley.

Cars don't have skin, so they don't care about windchill.

 

Letting it sit 10 minutes so the heater gets going and the car is toasty warm, well, thats a whole different story though

 

I let mine run at least 5 minutes. Thursday morning (wednesday night) we had temps as low as -30 with wind chill, i think it was -15 out. I let my garage heater run and decided to take the truck to work... well going from 40 deg. to -30 to -50 on the highway... in under a minute, lets just say the paint didn't hold to well, and now I have to redo the whole hood! Couldn't figure out why it was 'snowing' but it was just paint chips hitting my window

 

There is definately a difference in oiling when its cold though. Yeah, multi weight and all that but still, when its all cold its not the greatest on an engine to start it and just start flogging on it in freezing temps. I have had several cars brought into the shop because of cold weather oiling. "my car taps and stuff if I start it and drive off". Every year when winter rolls around at least 2 or 3. In a perfect world would this happen? No, the oil would work like its supposed to. But in the automotive world its not always like they teach in books.

 

No, but start it and drive it doesn't mean start it and flog it.

 

It takes more than just a few minutes to get the oil up to temp also. Letting it run 3-5 minutes isn't going to do hardly anything as far as warming the oil up. I've got an oil temp gauge in my Corvette, and letting it idle to warm the oil up takes FOREVER. Think about how long it takes to boil a pot of water, and thats with an INSTANT heat source. To heat the oil up, the block has to get hot first. I'm with the rest of the group, let it run 30 seconds or so, and take it easy on the road for the first few miles.

 

Heating it up a little has nothing to do with getting it to operating temp. Thats a whole nuther critter.

 

I know that, but just a couple of minutes of runtime is barely going to make a temp difference on the oil. A warm up in the morning is to just get the juices flowing before rolling.

 

Up here in the mountains we see overnight temps as low as -5 (I know not as cold as some places, but still plenty cold). My rule for the winters is to let the car "warm-up" until I can feel just a little warmth coming from the heater. Usually only takes a few minutes with the fan on low. in the summers where we get up to 105 I will just give the cars until they come off of their idle circuit, which is only less than a minute. The basic idea is to warm the oil enough to be providing proper lubrication to the engine, don't forget there are parts in the engine that receive thier oil from splashes off of other parts, oil does not flow as well in colder temperatures especially if you are running a heavy weight race oil.

To give an example, my friend and I both bought trucks about the same time with very close to the same mileage. We both use Castrol Syntec 5w-30, and the engines are both larger V-6's (Ford 4.0 and Chevy 4.3). We have both put a little over 55,000 miles on our trucks over a few years and his had a few less miles to start with, and both were in perfect running condition when we bought them. He is a "turn the key and drive" guy who insists that warming a car is bad for it, and I use my afore mentioned strategy. His Chevy now is making so much valvetrain noise it sounds like a typewritter, while my Ford still sounds like it did when I got it. There is likely other contributing factors as well, but I see largely that his warming technique is the major culprit.

 

it depends on your tune but my car always ran smoother and better once warmed up. Before driving it anywhere, even in the summer heat, i let the car idle abit to get into closed loop and warm up abit.

AFter the first initial startup of the day after sitting all night or even for days as i dont drive the car much, the car is fine. I can go somewhere, leave it parked for a few hrs, then go back and start it up and drive right away as the engine is still abit warm.

Maybe it doesnt do anything but i certainly feel it doesnt hurt. Even with my 383 i've done this but i ran an open loop tune and my first initial startup tune ran rich so i let the car warm up abit before driving, then it was fine. That was just my fault at not completing the tune.

But the oil is designed to operate best at certain temperatures. its viscosity changes with temps so if its chilly, i would definately let it warm up abit just to get the oil as viscous as you can. Every little bit helps when it comes to protecting your motor for the long run

 

To the original poster, I live in the same area as you DFW. Year round, regardless of temperature, I bump the key let the engine run long enough that the startup high idle spike drops down from 1,600 rpm down to 1,000, then drop it into gear and go. I drive down my street roughly 1 block, then hit the access road. The access road takes me about 1/2 mile before the on-ramp, then I am on the throttle (usually near WOT, the ramp is short), up the uphill on-ramp on my way to the 70-80 mph 6:30 AM traffic on 183 east bound in Bedford. Idling a cold engine is a good way to wash the rings which wipes out the rings and cylinder walls giving you poor ring seal. Run the correct grade oil, I run synthetic 5w30, and its not an issue.

If you both had 4.3s, you would BOTH have valvetrain noises. I have not been around a 4.3 or even later L31 350 that did not have valvetrain noises.

 

Cold oil is more viscous than hot oil.

 

I'm using the wrong term here or stating it wrong. Cold oil is thicker, being more viscous. You want warm oil as it flows better and should lube the motor better to provide better film for the parts.

 

Cold oil lubricates just as well as warm oil.

 

Not really relevant to the topic, but the 4.3 in my S10 has over 135 000 miles on it and it doesn't make any valvetrain noise. None out of the ordinary anyways.

Both my Camaro and my S10 have over 135 000 miles on them and would see winter temps occasionally below 40 degrees, without the windchill. I never idle my engine more than 60 seconds even in the worst cold, and I've never had a problem.

 

I always let my truck warm up for 10-15 min. in the winter, but it's a diesel so that's a different story. Although one thing I think would be universal would be tranny fluid. Ideally I think it'd be better to have it be warmed up so it can circulate better. For example, in the technical manual for my Allison, it says the trans. will operate in limp mode until it gets up to 70 degrees F. So that is part of the reason I let it go for a bit longer in the winter. I could be wrong, but it just seemed like a good idea.

Truck's for sale, by the way... if anyone's interested