General Question

jcs007's avatar

Why do you have to wait for a car's engine to warm up before you start driving? What happens if you don't wait and you start driving right away?

Asked by jcs007 (1770points) March 5th, 2008 from iPhone
Observing members: 0 Composing members: 0

14 Answers

jiboo420_'s avatar

I live in the mountains and I never warm up my car. I just start driving. Something bad is probably gonna happen to it in the long-run though.

drive_by_dev's avatar

The oil needs to warm up to obtain the proper viscosity. Also rapid thermal expansion of the metal parts can cause fatigue. The modern engines of today can handle all this much better, so in the long-run, and with the cost of gas, unless it is really cold it may not pose such a great problem.

Fallstand's avatar

I’m not sure how it is for other cars but in my VW manual is says to NOT let your car warm up. You should begin driving right away but not to gas hard.

nikipedia's avatar

When I was in high school my friend started driving his POS without warming it up and it stalled.

PrancingUrchin's avatar

@drive by dev. Youre exactly right

Also warming up the engine may help heat up transmission fluid making shifting much smoother than a cold start.

ishotthesheriff's avatar

@ fallstand, what year VW is yours? i’ve never heard to NOT let your car warm up…
i have a 74 standard bug.

tomsyelloplanet's avatar

When I run my car without warming it up, it does have harder shifts. Sometimes it just completely stops. Its a junker anyways, so I treat it like one.

infern016's avatar

I have an 88 bmw 325 manual trans, and the first thing I noticed was rough idling, sluggish shifting and acceleration. It would also stall out at times (when it was really cold). Later in the winter I encounted some mechanical issues that my mechanic “didn’t see coming”. I suggest just letting it run for at least a few minutes before driving just in case.

heyu1021's avatar

I work at a dealership and letting a newer engine warm for at least 30 secs to a minute is a great way to prolong the life of your engine. I’ve let every car I’ve owned warm, and I’ve never run into mechanical troubles. You can make it a habit… Like putting your seat belt on!

PrancingUrchin's avatar

Good point. Especially if there is ice or snow on your cargo start it with defrosters on and to let it warm up while you clean/scrape off the car.

Poser's avatar

The coldest it gets where I live is the low 30s rarely (that’s Farenheit for all you outside the US—near freezing), so I don’t have much experience with cold weather driving. I have heard, however, that it’s always a good idea to let the car run for about 30 seconds before pressing on the gas. When the engine is not running, there is no oil pressure, so all the oil drains out of the block into the oilpan. It takes a few seconds for the oil to start circulating back into the engine at startup, so giving your engine the time to allow this to happen before getting your RPM’s up saves lots of wear and tear.

gooch's avatar

This also allows for the oil to move up into the engine for lubrication before it runs at higher idle. When the engine is off oil moves down into the oil pan.

gooch's avatar

@ poser Didn’t mean to repost guess we wrote at the same time….good answer

tomsyelloplanet's avatar

Apparently a cold engine also spits out more CO2 than a hot one.

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