Featured So don't warm up your car. Just go after 30sec.

I have to confess, I never wait 30 seconds. The engine is not running until I am moving, and is not under load when cold.

If my driveway emptied onto a freeway, I might warm up.

 

THIS is why you should not let it idle very long before moving out.
That part about the oil draining off of engine parts is pure and total BS.
The oil pump is still running. All parts will stay lubricated.

I don't think "Smart Motors Toyota" is really very smart at all.

 

And why should we believe any of these sources? Which of the 4 sources cited have any credibility or track record of conducting tests that would back the claims they are making?

My understanding:

I start the car. The oil pump starts pumping oil immediately as it is driven by the rotation of the (ICE) engine. Oil squirts through the oil passages in the block to the head and does drip back down toward the oil pan where the pump can pump it up high again. Then there are things like the crankshaft, rods, cylinder walls and pistons which are all lubricated by the crankcase oil being splashed by the crankshaft rotating through the oil creating a mist that coats those parts. And as long as the engine is running (and it should be running in a hybrid until the engine is warm) this oil pumping and splashing should go on.

Now I can make an argument that you might not want to run the car to warm up for a long time. But for the minute or two in cold weather when you really want and maybe need the warmth...the engine is not yet warm.

My practice in cars built over the last 60+ years is get in, start the engine, fumble for my seat belt, select the accessory settings you desire for that trip, wait for any passengers to buckle up and then drive gently for the first few miles. Fortunately for me those few miles are frequently 25 MPH limited in my neighborhood and by the time I'm called to accelerate from a stop to 55 MPH my steering wheel heater and seat heater is working and I might even be seeing a little HVAC heat. And if I'm stuck out in the snow and/or ice, I'm wanting the defrost to help me clear the windows.

 

The last time I checked our Prius, O{2} fuel cycle tuning started about 45-50 seconds. Thereafter the ICE was optimizing for efficiency. Just drive the car and things work great.

Bob Wilson

 

there is some debate about what causes gen 3 head gaskets to blow

 

What kinds of engine parts are not getting oil when the engine is running but car is stationary?

I think I've seen some (unverified) claims of transmission parts not getting oiled, but that is separate from the engine, and ought not be a Prius issue.

Some days, such as today, it takes much longer than 30 seconds to clear the windows enough to drive safely.

 

It might be pumped to a lower pressure at idle.



However, this thread is the first time anyone's tried to tell me 8.7 psi would be insufficient to keep an idling engine slippery.

 

The whole notion that you have to let your engine warm up was true with some cars a 1/2 century or longer ago, but these days that's just as antiquated as the myth that a car isn't any good after 100,000 miles.

Truth is that not only are today's engines built to last for a 1/4 million miles or longer with nothing but regular oil changes and replacing the spark plugs once or twice, but you're wasting gas and polluting your neighborhood waiting for your car to warm up because your catlytic converter doesn't work until it heats up. If you have an elderly neighbor with respiratory disease who is regularly exposed to your cold engine fumes you could kill them and no one will ever know that you did that.

That being said, the other truth is you can drive your car 1000 miles and put less wear on the engine than when you first start up a cold engine, because it takes a few minutes for all the parts to heat up to their most efficient size/efficiency when it comes to engine wear. So it's best not to push the engine too hard until it has warmed up after 5-10 minutes of driving.

Beyond that, your comment about "stripping away oil from the engine’s pistons and cylinders" is not what's happening. It's not a lubrication problem so much as a cold engine has a slightly less accurate piston and cylinder size than it was designed for and it has to be at normal operating temperature to be the perfect size so there's minimal engine wear. As in a cold piece of metal is a very slightly different size than a hot piece of metal and that's why long ago you needed to wait a bit for your engine to warm up. But that's not true anymore.

 

An automatic transmission can have its fluid pump connected before or after the neutral point. Before, it pumps as long as the engine is running.

After, well, if the car is in neutral and not moving, it won't be pumping. The parts it needs to lubricate also aren't moving at that point, so it isn't a problem. These transmissions are flat towable as spinning the drive wheels operates the pump.

 

With our 3rd gen at least, on a cold start the engine’s just running at fast idle for the first few minutes, regardless of throttle demands. All propulsion is provided by hybrid battery and the motors. You can confirm this by listening to the engine as you accelerate and decelerate; engine speed just sticks to a fast idle.

this might make the Prius an exception to the fast take off need? Still, you get better mpg (save money) by getting gone, than taking too long…

 

Sometimes it's best to just start slowly driving as fast as you can...

 

Yeah this stuff is way out of date.

The next time I'm driving a carbureted vehicle with a sump full of 1970s motor oil, I'll let it warm up before I enter traffic. That way I can get 50,000 miles out of the engine instead of only 30,000.

We blew past all those limits ages ago, but these weird gatekeeping ghosts remain.

Just hop in and drive.

 

The Sonic also had a fast idle on start up. The main reason is likely to warm up the catalytic converter and oxygen sensors. Haven't noticed it in other cars, but it is likely also the case.

The article is right about idling a car for heat. Engines are more efficient, and smaller displacement. Not only will the cabin warm up faster driving the car, but it'll waste less fuel that way.

 

+1000

Without any definitions for "too much, too fast", another useless article.

How about some just leave 10 minutes earlier and/or get a block heater advice instead.

 

"Gas-powered cars need oil to keep their engines lubricated. When you start a car, an oil pump circulates the oil in less than a minute. But if you let your car idle to warm up the cabin, the oil will start to slowly drain away from the engine's key components since the engine isn’t moving the car."

Whoever wrote that does NOT understand the operations of an internal combustion engine!! Yes, oil is immediately circulating whenever the engine is started BUT if it's cold out the oil isn't as thin as you would like so it's smart to let the oil heat up a bit so ALL of the internal parts are lubbed. If small parts aren't, yet, lubbed well and you gun the engine to get up to speed to merge into the highway you aren't doing your engine any favors.

That's like folks who don't drive with their headlights on because they believe that tiny amount of 12-volt electricity gives them higher MPG's.....pure ignorance.

 

This whole discussion is ridiculous and a waste of time.
It's just another example of a "self appointed expert" who really knows little to nothing about how a car engine really works.

Don't worry. Be happy.

 

That portion is actually true. There is a tiny improvement in MPG by leaving the lights off.

But the greatest savings is after the crash from lack of light, not before. Whoever dies in the crash, achieves 100% fuel savings. They will never need any fuel again.

 

In Prius transaxles, the oil pump is driven by a shaft inserted into the planet carrier; it turns only when the engine is turning. That was covered in this thread in 2008, and probably others. I've just looked it up to be sure in the Gen 1 and Gen 2 New Car Features manual, and you can also see it in a Gen 4 transaxle at 5:18 in this Weber Auto video.

If you're thinking that's weird, I agree, and I don't know why they made that choice, but there it is. It is probably one of the reasons the owner's manual clearly states the car is not flat towable, the other being that the permanent-magnet MGs can't be stopped from producing a voltage, proportional to tow speed.

If the car is in neutral and not moving, but the engine is turning, the input shaft, PSD, and MG1 are also turning.