Car warm up


#1

Ok, so this is my pet peeve. There was a time (days of iron men and iron engines) when it was basically unheard of to start your car and drive off without some short period of time to allow it to warm up. I’ve always done it and I’ve always credited the long life of my cars to changing the oil regularly and warming it up before driving off.

But seems that I’m becoming a bit of a dinosaur in this regard. (Well, ok, in many regards.) My wife has told me all her friends at work say warming up a car is unnecessary with modern cars. Is that true? There’s a lot of moving parts and fluids in the engine and tranny that are designed to work best at running temperature, right? So, when they’re cold aren’t they subject to greater wear?

Note: I’m talking about gas engined autos not those new-fangled electric golf-cart car wannabes.

(old man) Dave


#2

Here it is, straight from the pros:

"RAY: But with modern cars, all you’re doing with a long warm-up is
wasting gas, increasing pollution, raising the temperature of the
planet and making yourself 10 minutes late for your chiropractic
appointment. The proper procedure is to start the car. If it starts
and keeps running, put it in Drive and go. Go gently (don’t back out
of your driveway and floor it right onto a highway entrance ramp),
because you’ll be warming it up during your first few minutes of
driving, but DO drive it.

TOM: If it’s bitterly cold out, like 10 or 20 degrees Fahrenheit or
lower, you can let it warm up for a minute or two to allow the oil to
thin out a bit and circulate completely. But other than that, if it
runs, driving it gently is the best way to warm it up."


#3

On my '79…it needs some carburetor time to ‘‘get with the program’’ …BUT…it gets that by virtue of ;
Starting it FIRST …
Then take out the windshield sun screen…
Then get out and remove the tire covers…
Then put in the rakes, trimmers, ladder, and mower…
That’s all it needs, the rest happens in minutes while driving.

The same ‘‘warm up’’, run time goes for the 06 and 08
Just start if FIRST…
Then get the kids, back packs and lunch boxes situated…
Then the seat belts…
And off we go to schools and work.

And here’s reasons that ‘‘warming up’’ is actually too little ;
— Only the engine warms ! —

You must be DRIVING to warm the…
Wheel bearings,
Transmission,
Axle gears,
Tires,
etc.

If only for the sake of winter defrosting, those run times are all it neeeds.


#4

Don’t bother with a warm up. Modern oils and engine materials make this unnecessary.

That said, don’t cold-start your sports car (or any car) at 10 below and slap the redline pulling out of your plat. That is pushing things a little too far.


#5

I start up, drive off in a few seconds, but keep the revs down in cold weather until there’s heat coming out of the HVAC.


#6

We’ve always done the rolling warm up in my family. The sometimes potholed gravel road that leads to the county road ensures a 15mph start until you need to gather momentum for the hill. Within a couple minutes the car is usually warmed up,even in winter. The only cars that really needed to be warmed up were the 1970 Datsun 510 and the '78 Rabbit Diesel.


#7

Thanks everyone!
Ok, I guess I’ll lighten up on my wife about this. She’s driving a new Honda Accord and maybe the warm up thing is not really needed here in SoCal. As for me, old habits are hard to break. :wink:


#8

The biggest reason you don’t any more is multi-viscosity oils. Back in the 60’s and early 70’s we all used straight weight oil. And we usually used a thinner oil in winter then summer. But the oil was thick when cold. Multi-viscosity oils are much thinner when cold…then they thicken up when hot.


#9

They don’t really get “thicker” with heat. They just thin less than if it was a straight weight. That allows them to use thinner oils to start with when cold and still have decent viscosity when they are hot.


#10

Right, TT - all oils, regardless of type/grade/whatever decrease in viscosity as they warm up. It’s how they vary from ‘standard’ viscosity vs. temperature relationships that results in the multi-weight ratings.


#11

Wrong wording.

5w-30 will be as THICK as 30 weight oil when hot…and 5 weight oil when cold.

Straight 30 weight oil will be 30 weight hot and almost molasses when below 0.


#12

That’s correct, but 5W-30 is still thicker when cold then when hot, guaranteed.

Here’s what’s going on, with some made up numbers just to make my point:
Table of viscosity:

Oil ‘weight’ / Cold (W) test / Warm test
30 / 500 / 50
5 / 100 / 10
5W-30 / 100 / 50

See, the 5W-30 has the viscosity of a 5 weight oil when cold, and a 30 weight oil when warm, but it still has a lower viscosity when warm. That’s pretty much guaranteed for any liquid hydrocarbon, regardless of additives.


#13

Wiki explains it like this:

The viscosity of a multi-grade oil still varies logarithmically with temperature, but the slope representing the change is lessened. This slope representing the change with temperature depends on the nature and amount of the additives to the base oil.


#14

What I do is start the car, then put the seat belt on, adjust the radio etc. then put the car in gear. That’s enough of a warm up unless its cold out and want the heater to warm the car up first. Back in the old days with carbs and chokes, when the engine was cold, the choke would be closed for a while and the fast idle would be on until the car warmed up. If you drove with the fast idle on, you’d be shifting into drive with a fast idle, and driving down the street at 20 mph with your foot off the gas. If you did that on a snowy or icy road, then hit the brakes, the rear wheels would spin and you’d lose some control. On slippery roads, it was necessary to kick the fast idle off before driving.


#15

We’ve spent lots of posts on this subject over the last few years.

In short, with fuel injection, and electronic engine management the drivability is no longer an issue with a cold engine.

However, we still need to get oil to the bearings and valve gear before we put a load on the enginbe.

That typically takes about 20-30 seconds at normal temperatures, but can take several minutes with a 10W30 oil at -30F., resulting in rapid valve gear wear.

So, take it easy and drive off gently. The oil weight is much more important that the warmup time.


#16

“The only cars that really needed to be warmed up were the 1970 Datsun 510 and the '78 Rabbit Diesel.”

…and the infamous Cadillac V-8-6-4 of the '80s.
If you warmed it up for…perhaps 30 minutes, even in the summer…it was slightly less crappy in its performance on the road. The thing was still unpredictable in terms of throttle response, but once it was “fully warmed-up” it was a bit less dangerous to drive.

“She’s driving a new Honda Accord and maybe the warm up thing is not really needed here in SoCal.”

No, DEFINITELY it is not necessary to “warm-up” a new Honda Accord in SoCal–or in most other places, for that matter.


#17

In SoCal that car is already warmer…sitting over night…than any of mine after being driven :wink:


#18

In the manual of my 2002 Toyota Tundra it says to warm up the engine for a couple minutes if the weather is below freezing.

For normal days it says - “After the engine runs for about 10 seconds, you are ready to drive.”