Is it bad to start and shut down car without proper warmup?

[DaveInLA]

Due to the street cleaning situation on my street (Tues = south side, Wed = north side), most people who park on the curb will start their car and drive it about 50 feet (
I recall hearing something about proper warmup for a car, so I actually will drive my car for about 2-3 miles before parking it again. Am I wasting my time?

 

[Pablo]

the worst - some cars handle it better than others, though.

The worst car I ever had for this is the Volvo 850. Otherwise a near perfect engine, you MUST fully warm it once started or next go around you will have some level of difficulty starting. That said the unburned fuel and water will play havoc with any oil.......

 

[moribundman]

I kinda doubt that driving 2-3 miles is any better than driving 50 feet with a cold engine. An engine needs at least 20 minutes for the oil temperature to come up to operating conditions. Until then, I seriously doubt that you'd burn off any condensation and fuel (dilution).

 

[DaveInLA]

Heh, just about everybody on my street does this. Some people told me that I'm a bit crazy for doing what I do. Good to know that I'm right!

However, when you mean "fully warmed up", do you mean the oil as well or just the coolant? Driving for a few miles will bring the coolant up to temp, but the oil isn't there yet.

 

[rpn453]

I don't think it really matters. If you drive 50 feet, it had a cold start and 50 feet of cold driving. If you drive a few minutes, it has a cold start, a couple of minutes of cold driving, and a couple more minutes where the engine oil never really warms up anyway. I'd save the time and the gas unless I've got somewhere to go.

 

[Hirev]

Unlikely driving 50 feet or driving 2 or 3 miles makes any difference. The oil does not warm up much at all in 2 or 3 miles. The bottom line is oil temperature and not coolant temperature makes the difference. Most motor wear happens in the 1st few minutes from a cold start. Try to do it when the motor oil is warm after coming back from work or a store for example.

 

[pitzel]

Yes, you are wasting time, and creating additional pollution as engines generally run rich for the first few minutes of their operation until the coolant temperature rises enough for the ECU to lean out the mixture.

Best practice, unless its below freezing, (or after heavy use in a turbo'ed vehicle) is to keep the run time on the engine to an absolute minimum. Saves fuel and wear.

Fuel dilution concerns, IMHO, are majorly overstated especially with respect to modern fuel injected cars. Short of vehicles with outright fuel injector problems, I have yet to see any significant evidence in the UOA section here of a vehicle being afflicted with a fuel dilution issue.

 

[Al]

I hate it when that happens. But what the heck.

 

[moribundman]

Well, you could always do the automotive equivalent of this:

 

[DaveInLA]

I'm confused.
So it's better to just drive the car across the street and park it? It's not always possible to do this with a warm engine.

 

[moribundman]

Well, it's better to have high wear and to produce a fair amount of pollution for a minute than having even more wear and producing much more pollution for a few minutes. I know your situation sucks, but it happens only once or twice a week.

 

[DaveInLA]

So the first few minutes after startup are ALWAYS going to put wear on the engine? What if I drive the car for 20 minutes (going to the store, for ex)?

 

[Razl]

The bottom line is to minimize the duration the engine runs on thick (cold) oil. As stated, this is the time you will experience the most wear, oil contamination, and worst fuel economy. So to drive around for the "heck of it" is the worst scenario. Again, minimize the engine running on cold oil.

Let's say you need to 1) move the car and 2)go to the store at some point in the day to pick up groceries. It would be best on the engine to combine the two - that is when you need to move the car, make it that time to go grocery shopping.

Now, if you didn't need to go anywhere but had to "move the car". Do just that. Driving it around for 2 minutes would be subjecting the engine to wear with nothing to gain.

 

[moribundman]

quote:

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So the first few minutes after startup are ALWAYS going to put wear on the engine? What if I drive the car for 20 minutes (going to the store, for ex)?

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Correct. Also, the colder, the more wear will be there. Wear is always considerably higher until the engine has completely warmed up. Engine parts and clearances are really designed for operating temperatures. After 20 minutes wear is dropping because the engine is getting close to operating temperature. BMW used to say it takes 40 minutes at highway speeds until an engine is full warmed up.

 

[02supercrew]

For awhile I was thinking that you had to move your car for the snow plows...

Since your lowest ambient temp in LA is the high for most of the snow belt, I seriously doubt the "cold thick oil" is that "thick".

You've got nothing to worry about by just moving the car and shutting it off.

 

[oilyriser]

The cars should be pushed to the other side of the street, without starting them at all.

 

[DaveInLA]

What about the comments about condensation and unburned fuel? Do those play a role at all in driving my car across the street?

 

[rpn453]

quote:

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Originally posted by DaveInLA:
What about the comments about condensation and unburned fuel? Do those play a role at all in driving my car across the street?

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They won't reach abnormal/damaging levels unless you rarely or never get the oil warm, like if moving your car across the street happens twice a day and is the only driving that car does. Even in that situation, regular OCIs based on time (such as those in the severe service schedule) would prevent any oil-related problems.

 

[mechtech]

You should drive it anywhere and anytime you need to without worries.
Just change your oil more frequently than normal.

 

[Shannow]

I'll stop my better half from running the car to "get back the spot that our neighbour's visitors parked in", as it's pointless.

If it's raining, and she needs groceries, and the grocery store is 200 yards down the street, I don't mind.