Taking It Easy on a Cold Engine - Why?

[Virtus_Probi]

It was around freezing at home again this morning and I was trying to baby my car a bit despite being in a hurry due to running about 5 minutes behind schedule...that makes a big difference in my commute due to school buses and the general exponential increase in traffic starting around 7am.
I got down to the "main road" and my car was not warm (the little blue temperature icon on my dash was lit), but it wasn't ice cold, either. I saw lights off in the distance when I was about to turn and thought about waiting for that car to pass, but it was slow moving and those drivers often have long "trains" backed up behind them...I gave it a little gas and merged in politely way before that car got near me (a work truck coming in off the next road down actually ended cutting him off in a rather rude way and then tailgating me).
Anyway, my slight reluctance to get up and go a bit in my car while it was short of being warmed up got me thinking...is there really a problem?
Now, my first car had a carburetor along with an indifferent maintenance plan, and I didn't get up and go in that thing before a decent warm up in cold weather because it might hesitate and even stall. Maybe proper adjustments by somebody in the know would have helped, but carbureted vehicles tended to have problems with starting and running in the cold and it was generally well worth taking it easy on them before they were warm if you didn't want to end up having your engine die just when you pulled out into traffic.
With a properly running fuel injected car that has been running at least half a minute or so, is there really an issue with just standing on it? The MOFT should be awesome given the temperature of the oil...I know that there will be some power loss due to the oil being so thick, but is there really a chance of damaging anything? Is anything going to happen beyond the engine feeling a bit sluggish? I would imagine some will say that it will take quite some time for the cold oil to make it through the whole engine and that it might be too thick to even flow through some channels at first, but I seem to recall reading some posts here that said these were highly exaggerated concerns at best.
And, does the presence of a turbo make any difference in the answers to these questions?
I know what what the long standing common practice is, just wondering if it really makes sense with modern vehicles.

 

[LotI]

Leave for work on time. Problem solved

 

[StevieC]

I start and go. I don't rev the snot out of the engine but I drive more moderately until it's warmed up. On extreme cold mornings I will let it idle for 10-30 seconds before I go.

Never had any issues.

 

[d00df00d]

On a cold start:

1. Oil is too thick
2. Clearances are too small
3. Fuel mixture is too rich

If you use too much throttle or rev it too high, you'll cause excess wear. You'll also load up your catalytic converter faster (more combustion byproducts) and may cause greater fuel dilution in your oil.

A turbo would worsen the excess wear if you're too eager to drive on-boost, and it's another part that'll suffer more with that too-thick oil.

Best thing to do on a cold start: let it idle for up to 30 seconds as StevieC suggests, and then pull away gently with the interior heater OFF. Drive mildly until it's up to temp. Then you can turn the heater on and drive as you want.

 

[ARCOgraphite]

Had to do this with my Toyota MR2 in the mid 80's. Route 495N Highway was about mile from my apartment in Shawsheen village in Andover, Ma. That engine was toast in a year. Burning oil and low compression.

Piston to wall clearance isn't settled in, oil flow through rings and splash isn't that good, valve clearance is high on SUB DOHC and some oil additives such as antiwear, anti scuff are not fully activated.

Does this make a difference? IDK. My Toyota may have been a fluke - but that was the only car that got flogged cold and it couldnt take it.

 

[knoas]

Originally Posted By: LotI
Leave for work on time. Problem solved


I agree that such is the best option,

However,

I do believe it is quite normal to be some minutes late from time to time and you might in find yourself in a hurry like the OP was in so it might be useful to discuss the topic a bit.

IMO if you dont do this every single day then nothing will be hurt, you are not red lining it 3 seconds after starting the car.

In my case i let it idle sit for 1 minute every morning and then drive off without pushing the car for first 5-10 minutes.

Good luck!

 

[ARCOgraphite]

My wife's last few Subaru have a blue cold engine lamp in the dash (DIC), and the manual says to drive conservatively until the light is off. This is a PZEV though.

 

[beanoil]

I baby my own vehicles, but am not as careful in the company lease. I respect it, but don't baby it.
That being said, if I need to merge or get onto a main road when cold, it's on. Last company car had well over 150k on conventional Valvoline Instant OMG changes, and never an ounce of injector cleaner, and driving "normally" when cold. Point to point driving, from customer to customer, so heat and cool cycles all day long.
I'm certain you did no harm.

 

[HonorAndHonesty]

I have a similar situation I live on Highway with a speed limit of 55 miles per hour. Sometimes I'm able to pull out and take it easy and drive 40 miles an hour for a bit till the engine warms up and other times there's vehicles that come up behind me so I have to run it up to the speed limit. Compounding this problem is the fact the direction I leave for work there is a slight Hill going that direction so it adds even more stress on the vehicle.

The other thing is both my vehicles are Toyota's and they will not shift into Top Gear until the engine warms up to a certain point unless you get the revs higher than I would like. The only way to avoid this in colder weather is let the engine Run 3 to 5 minutes when it dips below 40 degrees, and it could have to run for 10 minutes easily to avoid this when the temperatures are closer to 0. So I generally pull out and try to take it easy but sometimes the revs will get up to about 3500 before the car will shift into high gear.

I haven't figured out if it's a catalytic converter temperature or an engine coolant temperature parameter that has to be met and not to allowing the sooner shifting into high gear on the Toyotas but it's kind of frustrating.

In the end I have religiously maintained and babied several vehicles and ended up selling them before the engine was even close to being worn out and the vehicle certainly worth were not worth much more money by taking very good care of them, so now I just tend to try to drive them and not worry about certain things anymore.

I have always figured that quicker thermal expansion from driving an engine harder when it's cold would have more wear on head gaskets and pistons and what not, however maybe it's actually better because once you get the engine up the temperature there's less where and the quicker you do that the better I don't know.

 

[MrHorspwer]

Metal parts contract in the cold, especially aluminum pistons in comparison to their iron bores, leaving more piston-to-wall clearance.

Seals are cold and far less pliable, doubly important since it's holding back against high oil pressure caused by thick oil. Something to think about in your turbo.

Fueling strategy is extremely rich to facilitate proper combustion during the warm-up cycle. More chance for blow-by (remember the bit about piston-to-wall clearance) and fuel dilution of the oil.

Don't forget the transmission. Fluid moves slower when it's cold and that fluid is ultimatly what makes shifts happen. Clutches and accumulators fill more slowly, fluid pressure is less linear and controllable.

Engines are designed around all this, of course, and transmission calibrations take into account fluid temp. You can't cheat physics though. Material properties change when they're cold.

All told, generally driving like a normal person isn't bad. "Standing on it" is a different story... but it's your car.

 

[itguy08]

No need to. Watch some of the torture tests the auto manufacturers do. Put the engine in a freezer to the negatives and start it and immediately go WOT at full load. Do that thousands and thousands of times. Little to no damage done.

Sure when things are cold tolerances are looser but with a good load they also warm up a whole lot quicker so overall wear should be the same.

 

[Virtus_Probi]

Originally Posted By: ARCOgraphite
Had to do this with my Toyota MR2 in the mid 80's. Route 495N Highway was about mile from my apartment in Shawsheen village in Andover, Ma. That engine was toast in a year. Burning oil and low compression.

Piston to wall clearance isn't settled in, oil flow through rings and splash isn't that good, valve clearance is high on SUB DOHC and some oil additives such as antiwear, anti scuff are not fully activated.

Does this make a difference? IDK. My Toyota may have been a fluke - but that was the only car that got flogged cold and it couldnt take it.


I used to work off River Rd just West of 93, not too awfully far from where you lived. That was a crummy area to drive in during the rush hours (more like 3 hours morning and evening and much worse on nice summer or snowy winter Fridays). Really weird company that I didn't stay at very long, no regrets about leaving.

Interesting info, I guess I didn't make my point very clear in the original post and was asking more about just going wide open on it when "cold"/not warm rather than thinking of the rather modest throttle I gave it to get in before the possible "train" this morning. Your experience suggests that WOT is really a bad idea before a warm up!
Even when I'm in a hurry, the car will idle for maybe 30 seconds while I get my badge out, put gloves on, deploy sunglasses if needed, etc. The drive through my neighborhood will be at 20-30mph for half a mile as there will be kids walking to the bus stop, then I have a half mile coast down a steep hill. It's always going to be some time before I have any reason to get on it at all, and even then it's not like I am merging on 495! ;^)

 

[FCD]

Driving normally ( if you normal is banging the engine off the rev limiter 2 minutes after starting your engine the, no ) is the best and quickest way to warm up a cold engine.

But now, what do we define as cold? technically any start that is under the engine's operating temperature is a cold start, even 40C ( 100F ) is technically a cold start, but it doesn't matter wether it's +40 or -40C you should be gentle on a cold engine always, if you intend on keeping the vehicle for a long time and want to get the longest engine life possible from it, the time from when an engine is started until it reaches operating temperature and the thermostat opens and the oil is up to temp, is when the grand majority of engine wear occurs, why do big diesel engines in big trucks last millions of miles? because they see far fewer heat cycles than a gas passenger car engine, often those engines run for 10 hours or more at a time.

 

[oldoak2000]

I think you guys are over-thinking this;
unless you're running straight-paraffin in your engine-block (or it's minus 60 outside), that engine is ready to go seconds after you've got it started; (the tranny, however, may not be so 'ready' . . .

Use a full-synthetic if you have any 'worries', and go!

 

[StevieC]

This is why you wait and should be gentle when the engine is cold. (Depending how cold)

https://www.youtube.com/watch?v=MVn5OzuHtjg

 

[fenixguy]

You don't do it everyday... no harm done. I tend to "baby" my vehicles until they warm up. But I don't go out of my way (or my comfort zone) to cater to my vehicles either. If it's cold, I usually let it idle while I clean off the windshield or (gasp) let it warm up while I'm brushing my teeth. If I encounter the slow-vehicle-led "train" like you're referring to, I'll give it a little more throttle than normal to get ahead of them. I don't make it a habit but after all, I bought my vehicle to serve me, not the other way around.

To add: My '01 Civic was bought specifically for a long-trip gas-sipping car when I was traveling a lot (+30,000 miles a year). There were many times I would start it up cold after sitting all night and head right out to the interstate at 75 mph at 4,000+ RPM. Obviously a no-timing-chain, SOHC Civic is going to have less issues on cold oil than a lot of engines, but it never bothered me a bit.

In short, you'll never notice a difference but sometimes it can make you cringe.

 

[PimTac]

In my area when it’s cold enough to warm up the car just a little longer I usually have to scrape the windows.

Besides that, it’s good common sense to get the oil pressure up and the idle down before putting it into gear. The transmission will thank you. That usually takes about 30 seconds.

Or, follow the lead of someone who starts their vehicle in 20f weather, put the car into gear right away and floors the throttle. I like to treat my expensive rides with a bit more care than that.

 

[kschachn]

For me at least, there's a big difference between starting "cold" at 40F than at -25F. When it is well below zero all sorts of drama seems to go on and I'm not inclined to add to it all by taking off in a hurried manner.

 

[SilverFusion2010]

Idle 30 seconds then drive normally. Extra idle wastes gas. Your car will warm up much faster when driven

 

[LoneRanger]

Originally Posted By: ARCOgraphite
My wife's last few Subaru have a blue cold engine lamp in the dash (DIC), and the manual says to drive conservatively until the light is off. This is a PZEV though.


My '09 is not PZEV and has same blue warm-up light, and same statement in the owner manual. On cold mornings when I used to commute in that car, the blue dash icon would stay lit for maybe the first two minutes of engine run time. Owner manual says to drive conservatively until the blue light goes out.

Very wise feature, surprised more car makers don't offer it.