Idle? or Off?

The Taipan · 28-12-2005, 03:28 PM

OK, at the lights its clear, leave it in "D" or knock it out of gear, and
leave it running, if an emergency vehicle needs you out of the way you can
move, and its safer for all.

But my question relates more to a fuel usage vs. engine wear/heat problem.
Apparently you use more energy idling for more than 30 seconds than you do
stopping the engine and restarting again... that's fine I can accept that as
possibly being true, and started using it in places where it was safe to
shut down - eg macca's drive thru where you always have at least 2-3 mins
wait... but while waiting for my mcJack's Fried Chicken once I got to
thinking about heat soak, while the engine is running so is the coolant,
therefore oil temps stay stable, shortly after an engine is shut down, often
the oil temps rise due to heat soak, that would probably be OK if the engine
stayed shut down, but if you plan on starting shortly afterward would
certainly take much longer to cool off again...

After pondering this for a while, I decided to switch to thinking about
world peace and ask my expert friends on the internet... which is going to
protect my engine for the longest and possibly save fuel?

Mr. CVE · 28-12-2005, 03:54 PM

Umm,
My head hurts thinking about it.
Especially if your starter motor is a bit average.

pauljh74 · 28-12-2005, 03:56 PM

I'd say leaving it idling is better, then there's less strain on the starter motor and battery - If we're talking about a minute or so. Consider taxis do lots of Ks because they are running alot. In summer the heat soak can be alarming when you switch it back on after 5 mins and the temp gauge has shot up 50%, but it comes back down quickly as the hotter coolant is cycled through.

In the end you might use a little more fuel, but wear and tear on other parts will be reduced. 3 mins plus at Maccas - better to shut it off

Steffo · 28-12-2005, 03:59 PM

You'd be surprised how much fuel it takes to start an engine.

Plus starter motors and batteries are not cheap items to replace.

Leave the engine running. It's better for it.

LTDHO · 28-12-2005, 06:08 PM

I'd leave it running and in gear always at the lights. If I have to wait a long time at Maccas, then I'll switch it off.

Most cars runn all injectors on startup only so you use more fuel, plus the battary has to be charged, so fuel is used.

So unless your temp is very high, leave it running the heat soak will disapear once you are moving.

ltd · 28-12-2005, 08:05 PM

Leave it running.

This is for several reasons
1/ No heat soak unless your vehicle has a problem and the temperature is going up.
2/ No heat soak to the gaskets causing them to vulcanise and leak sooner
3/ Constant oil pressure providing much less wear (see a taxi)
4/ No startup wear due to minimal oil temp and pressure
5/ Less chance of a sudden cooling system failure due to spiking temperatures after shut down, as well as increased pressure from said rising temperatures.
6/ Less component wear due to less use (battery/starter)
7/ Less chance of any type of failure for any of the problems listed above.

**Mechan1k** · 28-12-2005, 08:35 PM

Quote:

Originally Posted by ltd

Leave it running.

This is for several reasons
1/ No heat soak unless your vehicle has a problem and the temperature is going up.
2/ No heat soak to the gaskets causing them to vulcanise and leak sooner
3/ Constant oil pressure providing much less wear (see a taxi)
4/ No startup wear due to minimal oil temp and pressure
5/ Less chance of a sudden cooling system failure due to spiking temperatures after shut down, as well as increased pressure from said rising temperatures.
6/ Less component wear due to less use (battery/starter)
7/ Less chance of any type of failure for any of the problems listed above.

Couldn't have said it better myself ... although I do knock it out of "D" at lights though ... a little less stress on the gearbox I find ... and less fuel used as well (hardly notice it though .... but it makes a difference for me).

JC · 28-12-2005, 08:44 PM

What about those new cars that automatically switch off at the lights, and then restart just be pressing the accelerator. I wonder if I can mod the AU to do that?

The Taipan · 28-12-2005, 09:25 PM

Thanks guys, now back to the problem of world peace...

**Mechan1k** · 28-12-2005, 11:05 PM

Quote:

Originally Posted by JC

What about those new cars that automatically switch off at the lights, and then restart just be pressing the accelerator. I wonder if I can mod the AU to do that?

Isn't that on the electric/hybrid cars to save battery usage to get further distance out of the batteries????

Biggoggs · 28-12-2005, 11:56 PM

I'd personally put in in D, then if someone rams the back of you, you don't roll into traffic. My driving instructor taught me to put the handbrake on at traffic lights, but the Falcon's umbrella-brake becomes a nuisance.

LTDHO · 29-12-2005, 08:17 AM

Quote:

Originally Posted by The Taipan

Thanks guys, now back to the problem of world peace...

It'll never happen, not in a million years. Stick to what can be helped.

Quote:

Originally Posted by Biggoggs

My driving instructor taught me to put the handbrake on at traffic lights

I was taught the opposite and I think it is illegal too.

megsy · 29-12-2005, 12:19 PM

i only knock it ouy of drive if im waiting for a goods train ( you know those 2 KM long buggers) then it's in park not in nuteral but i never turn her off (see formentioned reasons)

Biggoggs · 29-12-2005, 04:32 PM

Quote:

Originally Posted by LTDHO

I was taught the opposite and I think it is illegal too.

Why were you taught the opposite? But illegal? Rubbish.

ltd · 29-12-2005, 05:46 PM

Quote:

Originally Posted by Mechan1k

Couldn't have said it better myself ... although I do knock it out of "D" at lights though ... a little less stress on the gearbox I find ... and less fuel used as well (hardly notice it though .... but it makes a difference for me).

Me too. And you're absolutley correct about less wear on the gearbox. For the non believers, do 10000klms with the tranny in N or P at the lights, then do a fluid change. Now do the same klms with it in D and do a fluid change. Notice the difference in colour.

A mate who works for Holden in Adelaide told me that the climate is so hot and dry in summer down there that they have many commodores coming in with fried tranny's, and heaps of them on tow trucks because they blow their seals due to increased pressures and temperature when sitting at lights in D with the aircon on on a hot day. Problem is they develop so much fluid pressure that they get extreme temperatures and pop the main seal. Also they suffer from torque convertor problems for the same reasons but we don't need to go into that now. He said that their service managers advise customers to pop them into P or N when idling at the lights with the aircon on.

vztrt · 29-12-2005, 05:49 PM

Quote:

Originally Posted by ltd

A mate who works for Holden in Adelaide told me that the climate is so hot and dry in summer down there that they have many commodores coming in with fried tranny's, and heaps of them on tow trucks because they blow their seals due to increased pressures and temperature when sitting at lights in D with the aircon on on a hot day. Problem is they develop so much fluid pressure that they get extreme temperatures and pop the main seal. Also they suffer from torque convertor problems for the same reasons but we don't need to go into that now. He said that their service managers advise customers to pop them into P or N when idling at the lights with the aircon on.

Wouldn't that be a problem with the Ford tranny's as well??

Aussie_Geo · 29-12-2005, 07:11 PM

Quote:

Originally Posted by vztrt

Wouldn't that be a problem with the Ford tranny's as well??

Just another reason to go the manual :hihi:

wow that will throw a cat amoungst the pigeons.

cheers

Peter

4.9 EF Futura · 29-12-2005, 07:17 PM

Quote:

Originally Posted by vztrt

Wouldn't that be a problem with the Ford tranny's as well??

No problems as of yet! Yeah, i tend to go to N at the lights but never turn the engine off.

Just pay attention coz these engines take forever to rev down from 3000rpm, lol.

ltd · 30-12-2005, 01:38 AM

Quote:

Originally Posted by vztrt

Wouldn't that be a problem with the Ford tranny's as well??

No, apparently they have a different pump, as well as having a more sophisticated valve body/solenoid arrangement. Fords old 3 speed did however suffer similar problems. Also, ford started fitting seperate transmission coolers as standard to the range from EF onwards whereas previously, they relied upon the engine radiator to do the job. In actual fact, on the EA2 to the ED the four speed had problems with fluid temperature on hot days, and the units would often go into limphome mode (locking it into 3rd gear) until the radiator could cool the fluid sufficiently ie not sitting in traffic.

ltd · 30-12-2005, 01:43 AM

And before this gets too far, by pump I mean impeller.

So at idle the ford box has lower fluid pressure than the holden box at idle.

This is not to start a holden/ford bashing thing; it's just reliable information from some tech guys in Adelaide, and I must admit on those really hot days I have seen a few dump their fluid. But I emphasise that it is not all of them, just some and that is more a result of contaminents in the fluid, or blocked filter screens, or general condition of the unit. Out of the box they didn't do it as far as I know.

mcflux · 01-01-2006, 08:17 PM

Quote:

Originally Posted by ltd

Me too. And you're absolutley correct about less wear on the gearbox. For the non believers, do 10000klms with the tranny in N or P at the lights, then do a fluid change. Now do the same klms with it in D and do a fluid change. Notice the difference in colour.

How does one do 10,000kms when stationary?

FordFan86 · 01-01-2006, 08:26 PM

Quote:

Originally Posted by Ghia5L

How does one do 10,000kms when stationary?

I was thinking the same thing. Ghastly business this is.
Unless it was on a runway, trying to gain lift? But the road was able to go the other way, at the same speed? Would the car be moving then or not?

NZ · 01-01-2006, 09:44 PM

Quote:

Originally Posted by Ghia5L

How does one do 10,000kms when stationary?

He means compare 10k orth of driving not using N at the lights but leaving it in D and then compare 10k putting it into N

geckoGT · 02-01-2006, 01:29 AM

No driver of an emergency vehicle will get upset at the 5 seconds it takes for you to drop it in drive, just happy that you have seen them. As for the park brake, on my advanced courses and emergency courses we were told keep your foot on the brake, that way you have 4 wheels braked instead of 2, lot more effective.

**Mechan1k** · 02-01-2006, 09:59 AM

I select D before the lights change .... I am ready for it.
Mind you ... with the amount of kms I do ... I am used to dropping it out of gear.

Quote:

Originally Posted by Aussie Geo

Just another reason to go the manual

wow that will throw a cat amoungst the pigeons.

cheers

Peter

I'd love to be manual ... but being a courier in Sydney ... and also towing ... the manual/clutch setup is weak really.

Mind you ... the manual gearbox can only handles 1200kg towing ... the auto can take 2300kg ... that's why for the first time in 11 years I chose an auto.

Auto is safer to tow with ... especially with the newer SSS boxes as well.