Home Forums Hunting & Shooting Hunter's Campfire Warming Up Your Car in the Cold Just Harms the Engine

In the thick of winter, the common wisdom is that when you are gearing up to take your truck out in the cold and snow, you should step outside, start up your engine, and let it idle to warm up. But contrary to popular belief, this does not prolong the life of your engine; in fact, it decreases it by stripping oil away from the engine's cylinders and pistons.
In a nutshell, an internal combustion engine works by using pistons to compress a mixture of air and vaporized fuel within a cylinder. The compressed mixture is then ignited to create a combustion event-a little controlled explosion that powers the engine.

When your engine is cold, the gasoline is less likely to evaporate and create the correct ratio of air and vaporized fuel for combustion. Engines with electronic fuel injection have sensors that compensate for the cold by pumping more gasoline into the mixture. The engine continues to run rich in this way until it heats up to about 40 degrees Fahrenheit.
"That's a problem because you're actually putting extra fuel into the combustion chamber to make it burn and some of it can get onto the cylinder walls," Stephen Ciatti, a mechanical engineer who specializes in combustion engines at the Argonne National Laboratory, told Business Insider. "Gasoline is an outstanding solvent and it can actually wash oil off the walls if you run it in those cold idle conditions for an extended period of time."
The life of components like piston rings and cylinder liners can be significantly reduced by gasoline washing away the lubricating oil, not to mention the extra fuel that is used while the engine runs rich. Driving your car is the fastest way to warm the engine up to 40 degrees so it switches back to a normal fuel to air ratio. Even though warm air generated by the radiator will flow into the cabin after a few minutes, idling does surprisingly little to warm the actual engine. The best thing to do is start the car, take a minute to knock the ice off your windows, and get going.
Of course, hopping into your car and gunning it straightaway will put unnecessary strain on your engine. It takes 5 to 15 minutes for your engine to warm up, so take it nice and easy for the first part of your drive.
Warming up your car before driving is a leftover practice from a time when carbureted engines dominated the roads. Carburetors mix gasoline and air to make vaporized fuel to run an engine, but they don't have sensors that tweak the amount of gasoline when it's cold out. As a result, you have to let older cars warm up before driving or they will stall out. But it's been about 30 years since carbureted engines were common in cars.
So unless you're rolling in a 1970s Chevelle-which we assume isn't your daily driver-bundle up, get into that cold car, and get it moving.

Warming up your engine to me means warming up the oil so that it flows more freely. That's why synthetic oil is the only way to go in most situations. It doesn't get too thick in cold conditions.

Carburated engiines don't change the fuel/air mixture? I'm supposed to take advice from someone who doesn't know what a choke is? (manual OR automatic).

Unfortunately, the author is right, drive gently until up to temp (does not necessarily apply to diesels at extreme cold).

This phenomenon hasn't yet been discovered in Montana, as thousands of people every day start their cars/trucks and leave them running to warm up. Failure rate of these burned up engines, hasn't manifested itself yet.

I start my truck every morning about 10 minutes before I take off. Ain't gonna change.

I wonder how many hundred of thousands of miles I've shortened the life of my vehicle engines by warming before going? I could, perhaps have gotten into the 3 hundred thousands. Of course every other darn thing on those cars was falling apart but at over 2 hundred thousand the motors themselves were all just fine! I seriously doubt warming the car makes any difference. Is this guy a member of green peace or some other conservation fruit factory?

2003 Dodge diesel - it gets ten minutes minimum when temperature is around zero. I really clatters when cold! I can't think that clattering does the engine any good.

I'm damn close with my 2002 Chevy
Warm it up about 10 minutes every morning before work.

Most reliable vehicle I've ever had.

1990 dodge truck has to warm up or it not gonna go anyplace when it it real cold.

I think most people warm their car for their own comfort and are not thinking about the engine.

How is it that for the better part of a century, conventional wisdom said to warm up your car in cold weather, and now all of a sudden we're to believe that we will leave a trail of blown pistons and rings in the wake of warming up the engine? Thanks for your opinion, but I'll continue to warm mine up. I've had several vehicles from a variety of manufacturers go well over 200,000 miles without blowing up. I'll take my chances.

The cost of turbos is enough to encourage me to do the warm up.
Those things need oil.

no warm up needed at my garage

50K BTU tube heater hangs above the two Tacoma daily drivers

5w30 syn too.........

I live where it can be very cold in the winter, and heated shelter for vehicles it not always available. I will not move a vehicle that is parked outside in minus 40 weather without first warming it up . Living in Chicago I doubt if the author truly understands what it's like to live in a area in North America where it's extremely cold for any length of time.

F

Majority of damage done to motors is during start up, not idling an extra 10 minutes.....

How long before the tires get round?

No doubt about it.

His theory depends on the assumption that just because the mixture is richer, excess unburned fuel will result, and the further assumption that all cars are the same in this respect. Nothing in the info provided attempts to make the first case, and I doubt it's worth his time to even try to make the second case.

Exactly...

Synthetic oil does a better job of keeping the cylinder walls wetted. Once the engine starts the oil flow keeps them wet almost instantly.

The author is an idiot. Our education system REALLY sucks.