Are Cold Starts Bad? Should you Idle or Just Drive to Warm Up?

Should you let your car idle to warm up? Or should you just get in and drive? Explaining what is best and if cold starting your engine is bad for it. Including description of the cold temp light in subarus.

[KurtofTrades]

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[jerryfacts]

I used to do engine and transmission rebuilds in my younger days. When the engine is cold the piston rings, bushings, and bearings are tight. Does not matter if it is a new type of engine or an older type engine. The thermal co-efficiency of the various metal parts are not exactly the matched and are nearly impossible to be exactly matched, and the cooler oil does not lubricate as well as when it is hot. The worse thing you can do is race an engine when it is cold. This makes for excessive wear, and can promote early failure.

When starting in the cold let the engine idle for about 1 minute max. On an extremely cold day you can idle it a bit longer. Remember, when starting on a cold day the transmission is also cold. Start driving but very gently. Don't drive a cold engine hard until it warms up. It will warm up faster when driven. Once the engine and transmission are at normal temperature you can drive the car normally, or if you want to drive it a bit harder.

With any engine and transmission, if you drive it easy all the time everything will last longer. Make sure you do your oil changes and maintenance on schedule. Driving hard will make for quicker ware of parts, burn more gasoline, and will shorten the lifespan of the tires. The need for making stops from higher speed and aggressive driving will also wear down the breaks much faster. Hard drivers make the service centers more rich!

[BLDYME]

I never sit and purposefully wait for the engine to warm up, however I don't just drive off the second the engine is running. Normally, as soon as I get in, the first thing I do is start the car. After that I go on my phone, connect to bluetooth, pick a song on spotify, chuck my vape in the cup holder, take off my coat, just basically do a bunch of boring "getting ready to drive" stuff. Once I'm done with all of that and the seatbelt is fastened, the car had been idling for at least a couple of minutes, which imo is enough to start driving. I still don't rev it high, since I live in the city there aren't many opportunities to red line it anyway. I drive normally, changing gears at 3000 RPM max. By the time I get to the motorway/highway the engine should be warm enough to floor it.

[charliec]

I live in the frozen tundra known as Minnesota. In the winter, i let my vehicle idle for a good 5-10 minues before I take off. During that time, i scrape the windshield and dust off any snow. By that time, I'm ready to go. I still take it slow until I get to the main road. By that time, I'm getting heat.

[pokedude]

there's definitely a happy medium. On exceptionally cold mornings I start it up and wait until I start feeling some heat in my heated seat before I get moving, which is usually less than a minute or two. The key is I NEVER rev the car above 2500 or so until the engine is fully up to temperature. Depending on your commute and if you need to get on the highway or not you may want to wait a little longer. My house is a pretty good distance from the highway, about 10 minutes drive to the onramp so no issues there but from work its literally about 30 seconds to the onramp so often I'll wait until the temperature gauge starts to move until I take off. Switching to full synthetic oil is a good idea too since it has better cold flow than regular oil.

[RichardC]

Hey man you made a great point about the engine idling with cooler oil and that possibly causing damage over the long run. But, you also don't want to RAPIDLY unleash the volley of combustion (immediately gunning it to the freeway without giving it a minute or two). Not letting your car idle for a minute or two before putting the engine and transmission under strain (transitioning from cold to hot rapidly) puts extra wear the engine metals and materials causing them to expand and contract faster than a gradual temperature increase. I think the answer is in the middle. Give it a minute or two to warm then start driving, not taking off immediately or letting it warm up too slowly and circulating that cold oil.

[emiliog.]

I think it’s ok either way. Oil changes are more important. Change early and often. Change your coolant early.

[johnmadsen]

Typically, a cold start will start with a slightly higher rpm. Once it’s warm enough, it will lower the rpm’s to the normal idle. It takes a couple minutes depending upon temperature.

[ec]

Modern cars are so fuel efficient that they will not burn enough fuel at idle to sufficiently warm the engine in any reasonable amount of time. Best to allow them to warm up for a minute or two and then drive off slowly and keep your revs below about 2500 rpm.

[rafaelrivera]

I’m a mechanic engineer and a mechanic as a hobby. If the thermostat is working right and depending on the starting temperature I will idol until the auto high ideal drops down to normal plus a minute. Usually for my six at 30 deg that’s about 3 minute. For my 4 cylinder that’s about 2 minutes. Then I stick to easy driving the next 2 or 3 minutes or until the temperature is within rage. Both of my cars are 22+ years old and running fine.

[JimV]

The happy place is somewhere in the middle. My argument against just starting up and immediately taking off, is that although you may be minimizing the amount of time that the car's oil is cold, you are adding more wear and tear actually driving it at say 2k-3k rpms vs letting it idle sitting at roughly 800-1200rpms for example. The other issue with cold running is that metals need time to expand and adjust to temperature differences, and sudden high rpm driving(assuming you do this) can put extra stress on all the components and lead to premature failure... My 2 cents.

[Barrie]

Another factor to warm up or not before driving is if your at the bottom of a steep hill and the only way to go is straight up - might be a good idea in that situation to warm the engine up a bit in the driveway, sit in the cold car for 5 minutes or so and rev up to 2000 after a minute or two and then tackle the steep hill.

[StoicOutlaw]

I don’t care how late I am I’m not moving till the rpms drop.

[lmybngr]

Most cars have a warm up process that lasts about 30-45 seconds in normal weather, up to 3 minutes in cold weather. You'll notice your rpm will be about 500-800 higher when you first start the car and will drop down after that initial 30-45 seconds.

[WOTPOLSKA_PRO]

Thank you for this opinion about warming car idle, I didn't think that it will actually be worse as its running on cold engine for longer time. Now I think its better to start engine, wait for a few seconds, go slowly at first, let it get some heat and then get it to higher rpm, wait a bit more if you got turbo or smth 😊

[jeremyrimmer]

Totally agree that it’s best to set off pretty much right after starting up. I’ll always drive the car gently till both coolant and most importantly the oil is up to normal operating temperature. When the car is parked outside on a cold snowy or frosty night, I’ll put a small 900 watt heater in the driver’s foot well. I’lll put it on a timer switch so as to save energy. This works really well. It’s so nice to come out to the car in the morning with a warm interior and clear windows!

[googleaccount]

Reaching operating temperature is more about proper expansion of all the different metals reaching their full dimensions.

[inyourhomefitness]

Spring, summer and fall, I never warm up, but winter here is brutally cold. It’s not the warming up I think about, but I can see out my windshield, side windows or back window. So if I can’t see out of those windows I warm up and if I can see out of those windows, I waited about 30 seconds and leave. But that’s very rare. I would love just to hop in my car and go but when you got an inch of ice on your windshield and can’t see zip, that does not work.

[GR]

Your engine will WEAR OUT Faster if you start driving right away, actually.
The goal here is to warm up your engine with the least possible RPMs. A good rule of thumb is warming up your engine for at least 3-5 minutes.

[rwestbrook]

well here's something they aren't telling you. every engine has an oil pump that circulates the oil when the thing is running, different viscosity oils perform with specified properties at different temps, automatic transmissions also have a oil pump that circulates the fluid when the engine is running, the engine drives the pump for the transmission fluid circulation throughout the hydraulic circuit, coolant also is being circulated when the engine is running via the water pump, to the radiator and heater core, engine temperature is controlled by the thermostat and radiator cooling fan. as long as all the fluids are within specification's and the component hardware is functioning as intended including wise ownership of the vehicle, monitoring levels and component conditions, you can let your car pre-warm for a 10 minutes plus pre-drive conditions without harming anything in the driveline in the cold weather, I myself have idled as long as 15/20 minutes. all this is happening at an idle or 1500rpm and higher, it has nothing to do with a carburetor, in fact I personally recommend it, get some defrosting done while you brush the snow off the thing and refill that travel coffee mug, get the sound tuned in and verify phone connectivity before hitting the road, safety starts with truth of the facts, and now you know.

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