Waste Of Fuel

[Riley'sLife]

My brother-in-law, an Insurance Claims Assessor, has recently started to idle the engine of his Toyota Vios for 5/10 minutes in the morning before heading off to work. He also leaves the engine running for a similar amount of time when he returns home in the evening, usually after having driven home more than 100kms.

I asked him why he did this – (he lives next-door).

He said because his friend at work, an Engineer, advised it.... “To warm the engine” in the morning ; in the evening “because, after a long trip, it’s not good to just stop the pistons in the engine, it’s better to idle the engine before turning it off. The engine will last longer if you do this.”“Oh, really?” I said.

My thoughts were- load of <deleted>! Later I got to wonder if this can have some beneficial effects in the tropics. Is he correct or is he just wasting fuel?

Anyone got a definitive answer?

Edited October 25, 2008 by Riley'sLife

[Carib]

He is waisting fuel, not only that, but idling a " cold" engine is not a good thing to do.

In the old days with the older type of engine oils, at least you had that excuse to warm up the engine.

Nowadays with modern multi grade oils this is absolutely unnecessary, in fact idling the engine will cause more wear, than giving it a normal working load straight away.

Modern oils will perform immediately, even when " cold" . In the tropics " cold" is not what we think of as really cold by the way.

Taking it easy the first few miles is a much better idea than just let it sit there idling.

If, when coming home the engine has had a normal working load and has the normal temperature, there is absolutely no need to let the engine idle before shutdown. We are not talking the older type of aircraft reciprocating engines here, nor race car engines.

Edited October 26, 2008 by Carib

[goldfish]

I had a neighbour who used to start her car in gear and screech off down the road as soon as it fired up. The main and big-end bearings didn't last long. I give my bikes about 10 seconds, the car a minute or two for the air-con to cool it, before driving off. With a new vehicle I do give a few minutes before turning on or off

[Riley'sLife]

I can partially understand letting the engine warm up from cold before "giving it some stick". But, I can't understand the logic of keeping the engine idling for a few minutes after giving it some stick.

[dumball]

I can partially understand letting the engine warm up from cold before "giving it some stick". But, I can't understand the logic of keeping the engine idling for a few minutes after giving it some stick.

The object of the excercise in allowing a 'Cold' engine to attain temperature before putting it under duress , is to allow the working parts to 'Normalise' . Pistons in particular need this , because a cold piston is both oval and tapered due to the vagrancies of the heavier masses not expanding as much as the rest of the piston . Yes , multigrade oils have improved in their many years of use , but that does not eliminate the wear factor of cold pistons which 'Tip' in the initial stages of warm up putting duress on the piston skirts .Allowing the engine to idle to cool after use achieves little to nothing apertaining to the wear factor .

[H2oDunc]

If the car has a turbo charger fitted then it is benificial to let the car idle for a minute before you stop to allow the turbo to cool a little. A lot of trucks here have a timer fitted so you can take out the key and lock the vehcle and the engine idles for a minute then shuts down. As for doing the same when starting it just allows the pistons etc to come to operating temp before putting ay load on them though 10 minutes is a bit much. Good fully synthetic oil changed regularly will also aid to keeping your motor sweet

[dave_boo]

I'm going to agree with the crowd that states that idling before and after is a good idea. You don't really use that much gas/diesel when idling, so that's not a major concern. dumball and H2oDunc gave very good reasons as to why it doesn't hurt anything to idle your vehicles. Another thing to consider, if you're a spirited driver, allowing the engine to cool down by idling forces the oil to keep circulating. This is major in turbos, but it can also cause oil to 'coke' up in other places.

[Gary A]

It's CERTAINLY a good idea to allow the engine to warm up a bit before putting it under load. Forcing engine components to heat up faster than necessary is hard on everything.

As far as idling a turbo diesel after a road run, that is not as important as it once was but doesn't hurt anything and is not a bad idea. Years past oil cooled turbo bearings would gum up badly if not properly cooled before shutting down. Modern turbos are now much better designed.

[BSJ]

When the little lights on the dashboard go out, your right to go! Idling the engine wastes fuel and adds un-necessary wear.

[dumball]

When the little lights on the dashboard go out, your right to go! Idling the engine wastes fuel and adds un-necessary wear.

Oh you are ssooooooo wrong , it helps PREVENT wear , read the answers given above .

[dotcom]

Big Bikes (1000 cc) I have always idled a couple minutes before setting off.

As warn as Thailand is I wouldn't worry about a car & never do. It warms up faster under load.

[JimsKnight]

My brother-in-law, an Insurance Claims Assessor, has recently started to idle the engine of his Toyota Vios for 5/10 minutes in the morning before heading off to work. He also leaves the engine running for a similar amount of time when he returns home in the evening, usually after having driven home more than 100kms.

I asked him why he did this – (he lives next-door).

He said because his friend at work, an Engineer, advised it.... “To warm the engine” in the morning ; in the evening “because, after a long trip, it’s not good to just stop the pistons in the engine, it’s better to idle the engine before turning it off. The engine will last longer if you do this.”“Oh, really?” I said.

My thoughts were- load of <deleted>! Later I got to wonder if this can have some beneficial effects in the tropics. Is he correct or is he just wasting fuel?

Anyone got a definitive answer?

He's right in part, for high-performance cars it's essential to warm them up prior to racing, this in turn, on the same principle is wise for ordinary driving, especially in a city environment.

For ordinary cars, less so, but still good if you have the time and don't mind using a wee bit of fuel.

My car (Skyline R34) has a turbo timer installed to let the engine idle a while longer instead after you remove the ignition keys. It just ensures

the oil residue doesn't linger in the turbo housing by dispercing it away. If I didn't use it the pipe would get blocked up over time.

Edited October 26, 2008 by JimsKnight

[culicine]

I generally don;t do much of a warm up, but crawl out my my fillage at less than 2000 rom. By the time I get to the gate the warter temp meter is up to its normal level. I don;t know about the oil though - i would assume that it takes longer to warm up. Mind you I use synthetic, so probably not too long. Need an oil temp meter!!

[VocalNeal]

My brother-in-law, an Insurance Claims Assessor, has recently started to idle the engine of his Toyota Vios for 5/10 minutes in the morning before heading off to work. He also leaves the engine running for a similar amount of time when he returns home in the evening, usually after having driven home more than 100kms.

I asked him why he did this – (he lives next-door).

He said because his friend at work, an Engineer, advised it.... "To warm the engine" in the morning ; in the evening "because, after a long trip, it's not good to just stop the pistons in the engine, it's better to idle the engine before turning it off. The engine will last longer if you do this.""Oh, really?" I said.

My thoughts were- load of <deleted>! Later I got to wonder if this can have some beneficial effects in the tropics. Is he correct or is he just wasting fuel?

Anyone got a definitive answer?

Just another example of Thai myth, like cell phones and lightning.

Good luck trying to break him of this habit.

If just by chance it happens to be a Vois Turbo then there is some validity but 1-2 mins would suffice.

[initiala4]

Thats not how you warm an engine. The engine is warmth by driving gently for the first 8-10minutes in order to raise the oil temperature. Starting the engine and leaving it idle will not raise the oil temperature to optimal temperature. BUT I would leave an engine running for about 2-4 minutes after hard driving, especially in turbo cars!

[dumball]

The temperature of the oil is not in question , it is the out of conformity of moving parts that pose the wear concern , in a normally driven vehicle , it is the first 1 to 2 minutes of initial start up where the most wear takes place . The longevity of a prior to driving engine warm up , shows up over the long period , as does regular oil changes and maintainance schedules .

[BSJ]

dumball: Oh you are ssooooooo wrong , it helps PREVENT wear , read the answers given above

I read them. I didn't say drive like a maniac on a cold engine. Drive steadily and your fine. With the fine tolerances in a modern engine with modern lubricant you can't do any damage.

[dave_boo]

I've got a dirty secret; I'm a bit religous about making sure that I warm large engines up; however my lil cbr 150 is jumped on and going from the second the starter button is hit. Rationale being that it's a dirt cheap engine and should it wear out I can get a new one on the cheap.