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Matthew Wright

Can we Open the 'Warm Your Engine Up' Discussion Again?

By November 8, 2012

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The question of whether or not to warm your engine in cold weather is the source of never ending debate. It doesn't matter whether you're a car person or you can't tell a spark plug from a hair plug, you probably have an opinion on the morning warm-up. Based on what I understand technically, I am against the morning warm up for gasoline engines. Diesels are a different story, because they rely on engine warmth to build up enough compression to run smoothly and efficiently. But a gas engine at cold idle sits there and spews pollutants into the air that would be eliminated with a quicker, driving warm-up. Some of you are thinking about lubrication, and the fact that your slow-moving cold oil won't be able to get to the top of the engine to lube your valves and such. Modern oil pumps can move oil fine when its cold. Further, in the old days an engine only had one or two ways to get oil from the oil pan at the bottom to the valves at the top. Modern engines have oil squirters all over the place, bathing valves, cams and other parts in oil as soon as the engine is moving. So I stand by my no-warm-up statement. There are some valid exceptions, of course, such as a mother who has to put young children in the car -- as a parent I understand that there's never a good reason to make the day uncomfortable. I came for opinions, so let them fly!
Comments
November 11, 2012 at 8:25 am
(1) Mike says:

Auto care 101: in the beginning the internal combustion engine needed both ignition spark and air/fuel ratio to be manually adjusted before the vehicle would perform properly. Then came automatic spark control. Then automatic choke (air/fuel) adjustment. Now fuel injection and better lube design / better lube. Still viable=don’t race a cold engine, so, are we talking warmup for the car, or the driver comfort?
M

November 12, 2012 at 10:10 am
(2) Sammy Too Cold To Stay Behind says:

I think every mechanic has there own opinion on this matter. I will leave the deep tech talk to the pro’s. All I can say about the matter is that the last time I warmed up my car was probably back in the late sixties.

Haven’t had any major car problems since then either. So it works for me to just jump in and go. I wouldn’t race it while it’s cold either. I would get it down the driveway first. Just joking, I stay pretty easy on the throttle for at least the first mile.

Though, I believe that the heater in the car will warm up faster driving it, not wasting the fuel in the driveway. Just my experience with my cars.

November 13, 2012 at 12:23 pm
(3) Steve says:

I have heard that in todays’ cars they are usually ” ready to drive” by the time all of the idiot lights and car seatbelt light goes off when you start your car. That is usually about 10 seconds.- During that time the oil is already being sprayed throughout the engine.
Avoid hard acceleration for the 1st mile or so- That is just common sense

November 13, 2012 at 1:02 pm
(4) Cyrano says:

Depends how cold… If you are in the frigid northern central states on a day that is near or below zero farenheit then your vehicle definitely needs time to warm before taking off. Even brand new cars drive better with a little idle time when it’s colder than a… If you have snow under the hood or in the vents, its better to have a warm engine to melt that off before you head out. It also allows your battery to bounce back when it’s put to the test. One other item that is crucial to warm up is safety. A car that is not ready to drive when the defrost/defogger is not functioning properly yet. Lets say its very cold and you turn out onto the road and hit a moist air pocket. You turn on the defrost and nothing because your car hasn’t built up enough heat to undo what old man winter has done.

November 13, 2012 at 3:13 pm
(5) Craiger says:

This is an interesting topic. Most seem to agree, start the car and drive it easy the first few minutes, to get it warm as soon as possible. I try to keep the revs below 3000 rpm until the temp gauge is into normal range.

If you are parked outside and there’s frost, ice or snow on the windows, it’s much easier to clear off warm glass than cold. I quickly learned that growing up in Minnesota.

The point about having a warm car for young children or seniors is valid. Otherwise, given good vision out the windows, I think it’s best to just start driving and taking it easy. I like to test the traction for steering and braking if there’s snow or ice on the roads on a deserted street before I’m out in traffic so there are no surprises.

Common sense goes a long ways. Take it easy with an ice cold engine. I like that modern cars use lower vis. oil. My Honda manual calls for 5W-20. Temps where I live now seldom get to zero and I think that viscosity is fine for my car.

November 13, 2012 at 5:31 pm
(6) Emilio Socci says:

Hi: I read the comments and did not see the mention of synthetic oil… It seems from people I know; They tell me, go with synthetic oil. One question is does the synthetic oil have superior viscosity that will remain in the bearings? particularly the main and rod bearings? To explain my
reason further,
I have a 3.8 engine in my windstar 70,000 miles no problem. My sweet 16 year old daughter drove a similar version to school every day. After 35,000 miles the bearings were actually worn down to the copper. Don’t ask ! Does a school girl ever warm up an engine?

November 13, 2012 at 6:31 pm
(7) Bill says:

Emilio,

Of course a 16 year old girl doesn’t concern herself with the viscosity of the oil in her crankcase assuming that is what you put in her car.

Here’s another take on this subject. I too HAD a Windstar. I wonder if the sweet 16 daughter’s Windstar always had ENOUGH oil in the crankcase to lubricate those bearings, and didn’t run it W/O enough oil a few times. That would be the death of the bearings for sure, not the viscosity of the synthetic oil.

Both the original and replacement 3.8 liter engine Ford put in my Windstar leaked oil at a pretty good rate, which is why Ford replaced the first engine, even before 30,000 miles. Did the sweet 16′s daughter’s van always have sufficient oil in the crankcase? She probably didn’t check it regularly.

My 2012 Chevy Cruze requires synthetic or semi-synthetic oil in it;s turbocharged 1/4 liter engine, so I’d guess those oil’s viscosity isn’t in question.

November 13, 2012 at 6:54 pm
(8) John says:

Been a mechanic on auto/truck/small engines for 45 yrs now. I stand by warm up before driving. seasons in northern areas play a bigger part where oil viscosity is a factor. cold temps contract/tighten tolerances to the point of resistance to motion which creates excess stress on components. physics! most folks don’t take off easy on a cold engine. In warmer climates it’s a bit different. My training and experience have served me well over the course of time. but..hey that’s me.

November 13, 2012 at 7:59 pm
(9) Brian Snyder says:

I remember when You could count in the snow of every driveway the number of times the neighbour had started his car that week by how much soot was in his driveway. The days of carburetter and chugging cold engines has gone,replaced by injectors that only stay rich for a very short time and there is no soot in the driveway. Now I like to go out after my morning coffee and climb into a warm car and a warm battery at -20 F. ( never know when any car may stall) In this province in winter 3 things will get you a ticket quicker than a drink, and they are:

3) Lack of winter tires (call it impeding traffic)

2) Sow on the hood roof or trunk( causing a impediment to the drivers behind

and the no. 1 reason!

10 Frosted windshields (inside as well as out) of any front, rear or any window that the driver needs to drive

November 13, 2012 at 8:08 pm
(10) HB says:

I agree with John,warm up before driving,at lease a minute or two then take off slowly

November 13, 2012 at 8:34 pm
(11) Ray says:

what about rpm’”s? when i start the car, rpm”s are pretty much on the 2000-2500 until it warms up a bit. Would it do anything shifting to drive and rpm”s go down so sudden?

November 15, 2012 at 3:02 am
(12) Raymond says:

I agree that there may not be the necessity of warming up the modern petrol engine but perhaps a compression engine the need may still exist.
However, it’s also not of any disadvantage if one decides to start the engine as he prepares for the ride therefore it’s not mandatory.

November 16, 2012 at 3:04 pm
(13) Drew says:

I don’t think a warmup is needed, or good for the engine. As soon as the oil pressure light is off, the car has oil circulating. If the car just sits and idles, the warmup process is prolonged. On cold startup there is also fuel wash at idle. That means the fuel washes the cylinder walls down, and gets into the oil. With 10% ethenol fuels this can lead to the build up of white sludge in the oil pan. Just my 10 cents

November 21, 2012 at 8:48 am
(14) Lee says:

Heres my take on this….

I am a Mechanical Engineer and I know quite a bit about metals. I tend to think that if you don’t warm up your car in cold climates like NH where I live, your getting unexpanded metals moving rapidally possibly causing more wear over a long period of time. Now, obviously when you buy a new car, the manual does not state to let warm for 5 minutes before driving. The car companies would have severe problems (I know, I work with GM, Ford, and Chrysler) with engine failure. But, is it the difference on if your car will reach 150,000 or 250,000 with or without smoke? it also depends what you drive… Foreign cars like a mid 90′s Honda Accord would run on a quart of oil to 300,000 miles… But, a Chevy Corsica would crap out at 45,000 miles… I feel like it’s how good was the car broken it at day 1 to day 14. Was it beat? Floored? or babied and let the tolerances stay where there intended to be between cam lobes and valve seats or are they now a little larger causing excessive smoke down the road. My conclusion is warm you car up if it’s below freezing or atleast “sit in your freezing car” for atleast 30 seconds to a minute and let that oil that “We all know is “SUPPOSED” to get up there is UP there” and doing it lubricating job. Oh, one more thing… Your TRANNY which most people forget is there and IT DOES NOT RUN OFF ENGINE OIL needs to build pressure as well. So, while your engine has been doing what it should.. Don’t forget about that costly metal box below your feet that also likes to build pressure and lubricate it’s clutches and gears.

November 21, 2012 at 12:44 pm
(15) Emilio Socci says:

Thank you for all that: One more thing…LEE! I think the 3.8 liter engine had aluminum heads. different metals and different expansion rates may contribute to short life. I agree that a good habit is; In below freezing temperatures wait till your hands are warm.

November 12, 2013 at 3:11 pm
(16) mother fucken G says:

always warm up your car cause its also hard on the belt to take off right away. if you drive right away your cylinders are going to start getting glazed you may break a piston ring if they arent lubricated

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