daking1959

I let the engines on most everything I have warm up a little, before leaving..
now Iam hearing its not a good idea.
Start it and take off..
opinions?

abqhudson

Start it and go. Just don't aggressively accelerate or redline the car before warm up. Common sense rules. YMMV.

mis3

+1

This is why I do. I live in Toronto and it can get very cold in winter. At extreme cold weather, I would warm up the car for maybe a minute.

Fatz

My opinion has been that the reason for the warm up is because of the viscosity of the oil and heating up the catalytic converters. Once the oil is flowing well enough to replenish the film protecting the engine from the last runs, probably 20-30 seconds, the engine is good to go. The rest of that warm up is for the cats, so you minimize the pollutants.

I generally let it run at 30 seconds or so on cold startup. By the time I get out of the neighborhood the engine temp is near normal.

shadenfroh

^ What he said.

I like how the car keeps the RPM higher for a bit after a cold start to get things flowing. After the RPM drop I wait a couple more seconds and drive off to reach operating temperature as quickly as possible and minimize cold operation.

Reanimation

Well I have always let the engine Idle for a minuet or two in temps below 10 degrees because when I changed my oil once I noticed how thick and gloopy the old oil was the next day, and that's 0w30.

sailorben

Problem is while the engine oil is warm, the drivetrain behind the engine isn't warmed through. Hence its still not ready to be driven any harder than if it were just started. It does say in the handbook to start and go asap. Warms this up more evenly, prevents unnecessary combustion...

merceBENZ

Wow, I didn't know that. I always let it sit for 10-15 minutes on subzero temperature.

mis3

This is exactly what I do.

Some people do warm up the car for 10-15 minutes; especially people with remote starter. Question is besides gas consumption, does this practice harm the car in any way?

merceBENZ

If I don't warm up the car on very cold mornings (35 and below) it shakes badly on a highway and very hesitates during acceleration. Acceleration is sluggish itself on cold engine.
If I do warm up (10-15 minutes) I get non of them. Plus I don't have to scrape windows and interior is warm. (no garage)

Zavato

I figure it like this- if i need a couple of moments for me to warm up, I'll give the same to my car. Warming up for a few minutes will burn gas but cause no harm.

mis3

Just found this:

http://www.popularmechanics.com/cars...-harms-engine/

shadenfroh

Warming up the car by letting the engine idle will cause harm 100% of the time. This is simple physics, it's not really for us to debate. If your mechanic assured you that it doesn't, you just haven't prodded him enough.

One point of wear is the engine. The article mis3 posted is great at explaining how "warming up" does little to warm up the actual engine, even though warm air fills up the cabin.

The other point of wear is everything between the engine end the road. Transmission and driveline do not get warm by sitting. And when you drive off thinking your car is warmed up and ready to be pushed, these thing take a beating.

merceBENZ, you have another problem with your car. It should run without hesitation, even it it's been sitting in sub-zero temperatures for a while.

Zavato, this argument is as old as "What spark plugs should I use?" and "Should I use MB-Approved oil or can I just go with Johnson's Baby Oil?". Make you own decision, it's your car to bugger up. Just don't argue with science with made up arguments. You can believe something to be true, but that doesn't necessarily make it true.

insame1

I just wait till the RPM comes down the first time then off I go.

Rudeney

Actually, an automatic transmission will warm up with just the engine running since the torque converter is heating the fluid and the pump is running which will circulate it. But that point is moot because there really is no sense in letting a modern engine warm up anyhow. I don't worry much about it here as it doesn't get bitter cold. We see some single digits (Fahrenheit) maybe one or two mornings a year. At the most, I wait until the idle speed drops below 1,000 before putting it in gear.

shadenfroh

I left that out on purpose, as I feel it might stir up more pointless arguments. Also I don't really count this as warming the transmission up, since a bit of lukewarm oil will always lose to a big lump of frozen metal.

merceBENZ

My car is 100% fine. I guess everybody has their own understanding of "hesitation in cold weather".