How letting a car idle when it's cold out can damage its engine

Utah winters are harsh on our cars. By warming up our rides in the driveway before we take off we could be making things even worse. Debbie Dujanovic tells us how letting a car idle when it's cold out can damage the engine.

Aired: 02/01/2017 at 6:00 p.m.

[Alex-beoi]

My car has 390k miles I’ve let it idle for 10-20 minutes during winters its whole life. If this were true wouldn’t I have experienced problems by now ?

[dreuxgreaney]

Warming up a car won't hurt it. For God's sake man stop overthinking every stinkin rotten thing

[wizardsofwisconsin]

30 year technician here…this is a prime example of “stepping over dollars to pick up dimes”. The gas dilution problem was WAY worse in the days of carburetors, todays fuel injection systems and associated sensors know what they’re doing. Warming up your car is critical for general safety and getting the other fluids moving and up to temp, and changing your oil ANYWAY at 3-5k miles is key. Seeing some random guy putting pistons in a block doesn’t impress me as much as the general public just letting their vehicle warm up so the windows are clear and the wipers aren’t petrified to the windshield. As the previous poster said….don’t overthink this people!

[williamsantiago]

Do not listen to this guy, always warm up your engines. You don't need to warm up for 10 minutes or more but a minute or two is fine.

[luisalejandro]

“It’s metal to metal” yes genius that’s why you let it warm up so the oil can lubricante the engine before revving up

[fasteddie]

I have been a Machinist for 25 years and I know that machines run much better at operating temperature. A cars engine is a machine and needs to be warmed up to the proper operating temperature to run better. Besides, driving a freezing car is dangerous as it can fog up your windshield and couse poor visibility and may cause a driver to have an accident. Please warm up your car in cold weather its better for the engine components and safer to drive.

[jamessmyth]

The story is an absolute load of nonsense. These news outlets find people who are allegedly experts but have no actual clue. If you let an engine warm up the metal clearances expand slowly and evenly. If you start up and drive at high speed immediately, everything expands far too quickly and puts strain on components like bearings and pistons. This could lead to an engine failure if it's repeated often enough.

[willypete]

Nonsense - even lightweight oil needs to be warmed.

[antonleimbach]

This is the best advice a person who rebuilds engines can give so he will always have work.

[BillySBC]

This is absolute nonsense. WTH is this guy talking about? The oil circulates the very same way hot or cold, the only difference is your putting strain on cold components when you throw and ice cold drive train in gear. Ignore this guy.

[geoffre]

" let's gas strip away oil from the engine" .... If this occurs, which it doesn't, it would also occur if you drive to warm up your car. It would be even worse. Their reasoning makes no sense whatsoever. Even at idle the oil pumps will still function.

[bedrosnersesyan]

Idling your car for a few minutes, "is the worst thing you can do to it"??? I'm paraphrasing, but this man would take that quote back if he could.

[romanc.]

Good luck going right away with frozen windows and windshields. You need to warm the car to de-frozen.

[efallser]

So with carburetor idling didn’t damage the engine when it was running rich. But fuel injected will damage And a mechanic said that. lol.

[LoganRoberge]

Canadian here, been a mechanic for 15years + now. I can promise you that warming your gas engine to operating temperature before driving it is the best thing you can do for your engine . Taking off slowly and letting diff oils warm up and transmission oils etc will go a long way also. Starting a car at -30 and just taking off will end up causing premature wear on internal parts as they all expand at different rates …..

[CForged]

Scotty Kilmer says it’s not bad for a modern engine.

[NEWFIEBULLET]

Absolutely the dumbest thing ive ever heard. Ive lived in parts of the world where its - 50c and oil is like sludge. Literally having to put blackets over the front end and using propane heaters to warm up the oil. Try starting a vehicle in those conditions for a minute and go..wont get far

[sa-nnny]

These are the same types that will tell ppl they can wait until 10k miles to change their oil. "

[smarro]

I live in NJ, and in the winter I always warm up my cars, but that's for me. Remote start it's the best thing ever

[jjc]

how is idling different from driving if the unburned fuel is diluting the oil? does it matter that during idle the engine is at a constant speed and is not changing the oil pressure in the crank, pin or valve galleries? does the stochiometric somehow change if the car is being driven vs at idle? does it matter that even the newest engines have piston rings that have not made good seal around the piston until the rings get above 200deg? does the PCV valve suddenly only work if the car is being driven and not at idle? If you ask me this is an environmental request masquerading as a mechanical one. Here in Colorado an environmental group tried to get a "puffing" law (no idling during cold weather ) on the books due to environmental impact and were not successful 3x- then the environmental group changed their tactics and got police depts to sign on to the "puffing" referendum as a way to combat car-theft and it passed with 60% of the vote.