Do you idle your car before driving off ?

[KiwiTT]

This may seem like a silly question to most people here, but a letter writer in our AA Magazine has prompted me to seek some expert feedback before responding to the letter, which appears quite technical.

NOTE: I am still idling my car before driving off. As I have a turbo(s) I want it last.

Here is the letter

"IDLE TIP

I am concerned at the number of drivers cold-idling their cars in the belief that they are warming them up.

There are two functions that will warm up an engine, and they are work and friction. When you turn off a hot engine, all the oil drains away from all moving surfaces, leaving them dry. When you restart the engine the next morning, the engine is not doing any appreciable work, therefore any heat that may be generated by combustion is quickly dissipated by the cooling system. As the engine has not been run at high revs to apply high-pressure oil into all moving surfaces, heat can be generated by friction. Running an engine under these conditions can be disastrous.

The correct procedure is to start the engine and immediately drive it away under load. This is ensures that all surfaces are sprayed with oil and the fact that the engine is under load will quickly bring it up to ideal working temperature"

What do you guys/gals think ?

[Legnum Boy]

I don't hang around, although, on a cold morning, I will tend to wait a few mins to warm up (me, not the car ;) )
I did read that turbo engines don't especially like to sit at idle to long, because they need the oil at pressure, which is quite low when idling.
What I don't do is immediately go into high rev mode. I will always let the water temp gauge rise to the normal operating level, which although not meaning the oil is ready, at least gives an indication of heat in the system and engine. :rolleyes5

[Paul Beazer]

The correct procedure is to start the engine and immediately drive it away under load. This is ensures that all surfaces are sprayed with oil and the fact that the engine is under load will quickly bring it up to ideal working temperature"



Hmmm, not sure if agree about the sentiments above. I always thought it was a good idea to start the engine, then let it run for a minute or so to let the oil get around all the bearing surfaces etc, before then driving off gently allowing the oil to warm up gradually.
The danger in driving off immediately is like the bloke says "bearings are dry" so no lubrication on them! Surely hes contradicting himself?
At the other extreme, too much idling can carbon up the engine excessively, yes?

Paul

[Nick Mann]

I move away but keep the revs low until the temp gauge is moving upwards. I think this is the best compromise. If you don't work the engine at all, then oil pressure is lower and temp takes ages to arrive. I like to sit somewhere in the middle. And yes, I have always voted Lib Dem!! :p

[Kenneth]

Like Legnum Boy, I don't hang around eithier.

I don't thrash or boost hard until running temperature is reached (unless for some reason it's unavoidable, like getting into a small gap in rush-hour traffic)

I DID thrash my 1.8GDI galant cold, but thats because I have a steep hill to get up in the morning (Park hill, off Glenfield ) and the 1.8 wouldn't get up it cold at under 4000rpm. the VR4 does it in 4th at 2100RPM!

3000RPM in 3rd, doing roughly 60km/h seems to warm the engine up nicely and also gets the turbo spinning.

The statement about the oil pressure makes logical sense to me...

[wirdy]

I always idle mine for about 30 secs before driving off just to get some oil to the top end - just about the time it takes to cue some music on the CD or tune to your favourite radio station.

With modern thinner oils and cars like our VR4's (with improved oil sprays etc) the oil is moving around well from start up anyway so as long as you drive sensibly there is no real reason to sit for 'minutes' before setting off.

IMO the writer of the article is talking from where the sun don't shine about 'friction' warming the engine up.....if there was enough metal-to-metal friction to create appreciable amounts of heat/wear then any engine would self-destruct very quickly. Just go and feel the cylinders of your compressor when it's been working at max chat for 10 minutes, the head is hot due to air compression but the crankcase is still cold (and compressor cylinders aren't the pinnacle of engineering excellence either!). Cylinder friction in any engine is very very low even with the minimum of lubrication, if it ain't you've got big problems :-D

Two houses ago my next door neighbour had a new Peugeot 306 GTi -the idiot started the thing in gear, from cold, & thrashed it every morning away from the house - how I chuckled when it began to belch blue smoke after just 18 months of this behaviour (I thought it did quite well to last that long!). Just a shame this to$$er traded the car in for a new one & some poor sap got his abused 306 with its (probably) worn engine & (certainly) worn valve guides.

[Kenneth]

If I had a big bore exaust, I would be tempted to idle more... just long enough to wake everyone in a 4 house radius at 7am week days before leaving for work.

Maybe idle for 30 sec, 2000RPM for 30 sec then sit on the limiter for 10 sec. That should make me VERY popular
:evil1: :laugh:

[enigma]

If I had a big bore exaust, I would be tempted to idle more... just long enough to wake everyone in a 4 house radius at 7am week days before leaving for work.

Maybe idle for 30 sec, 2000RPM for 30 sec then sit on the limiter for 10 sec. That should make me VERY popular
:evil1: :laugh:


The houses round your way must be very spaced out! I can easily wake the whole street up!!! On idle!!! :D

[Nick Mann]

The houses round your way must be very spaced out! I can easily wake the whole street up!!! On idle!!! :D


See, everyone thinks that BDA's engine troubles are due to his extreme tuning and learning curve. BUT it is actually neigbours getting their own back! (That's it, just drop that ball-bearing in the inlet manifold!) :p




:topic:
Sorry!

[Nick VR4]

If you sit there idling you will be warming up the engine BUT not anything else
Gearbox drivetrain etc so not really much point also as above

It takes a little while to get oil up to temp so would be better just taking it easy for a few miles IMHO

[Kenneth]

The houses round your way must be very spaced out! I can easily wake the whole street up!!! On idle!!! :D

:laugh: I guess its probably a good thing you arn't not a smally weedy guy then ;)

hehe, actually I live in a Cul de Sac, smack bang in the middle with a few right of ways on eithier side.... I guess I was probably very conservative.

I used to have a motorbike with an exaust like that, ZXR400. straight through carbon pipe with a very large internal diameter. I used to get comments on how I could still be heard for 5 minutes after leaving the house.

[The Vee]

A cold engine at idle is when wear can occur. Oil will pressurise almost immediately, hence the oil pressure light goes out quickly, but this is bottom end. It takes a little longer to circulate when cold because of higher viscousity which is why manufacturers and oil companies develope thinner oils to speed this up while remaining durable at higher operating temperatures. Most oils are designed to be most effecient at normal operating temperature. A cold engine is also running a richer mixture so more bore wash will occur. so until normal temp is reached, I would drive the vehicle "normally" avoiding high revs or full throttle until warm. this way also the engine sensors will lean off the mixture quicker as heat is produced but the avoidance of high revs etc will reduce wear until all is warm. An engine with turbo(s) may be idled when hot for for half a minute before turning it off, as the circulating oil will remove heat from the turbo bearings etc and reduce the risk of failure.

[krisby]

on a cold winter morning I let it sit for about 30 seconds, but now in the warmer months I maybe let it sit for 10 seconds while I put my seatbelt on and turn the stereo on.

I remember though the castrol magnatec ad in the UK with the cars going "ow, owwww, owwwww", castrol were saying you should let the car warm up before pulling away or even flogging it.

[venomboy]

I remember the old advice used to be to idle your engine to allow the oil to become less viscous, but that was inthe days of 20w50 mineral oils. With modern 10w40 synthetics I would think a far shorter period if any would apply to normally aspirated cars, and as for turbos which rely on high pressure "float" then an off-idle warm up to keep pressure up would seem to be a wise precaution. Everyone knows we're not talking high revs from cold here, even with synthetics. There was a good point made about cool down for turbo cars as I have heard that sudden change from high boost/high heat states to low oil pressure at idle can wreck bearings.
VB

[Roadrunner]

Couple of points to note:

It's more important to wait till the oil has reached its working temperature before using high revs (but the lack of an oil temp gauge doesn't help ;) ) rather than just the water temp. The oil will take about 10 minutes driving from cold to reach its operating temp whereas the water temp will be up within 2 or 3.

Agree with the cooling down period to allow the oil to cool the turbos, but far better to run off boost for a few minutes (so allowing cool air to circulate through the whole engine bay) than to sit at idle (thereby generating more heat within the engine bay). One of the reasons that, on track, you should always have a cooling down lap, off boost and off the brakes if possible.

Fully synthetic oils don't suffer from the old problem with mineral oils in turbocharged engines where the residual heat of the turbos caused a chemical change in the oil ("cracking", if my old chemistry knowledge hasn't deceived me) and resulted in carbon deposits on the shaft which, over time, led to turbo failure.

Brian

[Kyoshu]

Yeah I ended up getting an oil temp gauge installed, cause I got paranoid about it. I just turn on the car while I'm getting the kids in for school & daycare and use that as a warm up period. Then I granny drive it till the oil temp reaches operating temp.

[Brind]

Very rarely thrash it, so pretty much start and stop it. :)

The only thing I do have to do is start it and sometimes stop it if it starts to tick, re-starting it makes the noise go, so that usually takes 30s to a minute before I get down the drive.
Sometimes just 'blipping' it past 3k stops the tick.

[-LegnumVR4-]

I remote start my car before i leave, 2 or even 5mins before i drive it. Temp gets up about 4 marks by then. I never boot it hard when i get in it. 3-4mins of driving gets everything up to temp including the trans.

I only use synthetic engine oil. Trans will soon be getting a synthetic.

[Pescha]

Well I have my car warming up while I shut up the house and get everyone organised (a very good mum & wife that I am) then slowly move off and drive grandma like till shes at running temp. Not sure what the neighbours will think now, as I have a 4 1/2 muffler and tip. So it is now slightly louder :$ But I do agree that the oil needs to warm up slightly :thumbsup: :lolz:

Pescha!

[foxdie]

Old thread alert! :seeking:

Stumbled on this but thought I'd add something to it. I've noticed the following things in my 13~14 months of owning a VR-4..

As I used to take my lunch break in my car and had an unreliable battery, I'd start and idle the car for anything up to an hour to put some charge on and cover me whilst I listened to the stereo.

Now, despite my engine oil being the good stuff (Amsoil) it hasn't been changed in 12 months, so I expect a slight bit of degradation of the quality of the oil, this however wouldn't truly account for the following, I believe it to be something more sinister;

1. As time has gone on, the tappet noise has been getting louder and louder on idle, this could be indicative of an oil change required, but also of something else

2. As Brind says, blipping the accelerator taking the unloaded engine rpm to about 2500-3000 RPM causes the tappet noise to completely vanish for a few seconds, after a few more seconds back at idle, the tappet noise returns

3. My Oil Pressure Switch died about 6 months ago, this was a gradual death (oil light would come on more and more, now after replacing the OPS, oil light comes on when ignition turned on, and disappears when engine started / running), could be related to extended idling

One theory I have is I've read elsewhere for another car that extended idling can cause oil starvation in the head / tappet area, this does seem logical as blipping the throttle / revs would cause more oil to spray over the tappets, right?

I could be entirely mistaken, putting it to you lot to comment / pick apart my logic :beatnik2:

Ps. Since recently upgrading to a 750 Amp battery I'll be idling my car a lot less, and changing the oil soon hopefully.

[Nick Mann]

Revving the engine increases the pressure to the lifters, which is resulting in better adjustment. You probably have dirt in one or more lifters, causing the ticking on idle. Mitsy themselves tell you to rev the engine to try and resolve the rattle.

I'm not convinced that idling a cold engine is particularly detrimental. Certainly not as detrimental as working a cold engine. My personal preference is still to drive the first couple of miles slowly to get the heat in the oil first.

[Rambaud]

I try not to rev the engine too much (max 2000-2500 rpm), until the oil is warm. This is likely to be at least 20 minutes.

[Turbo_Steve]

Hadn't seen this. The engine will be fine at idle pressure for ages - mitsubishi aren't stupid enough to design an engine that will fail through being started and run. What leaving it idling CAN do is ruin the oil quicker with carbon deposits and running it hotter at lower flow rates.

I start mine, very gently move it out of the garage (which is enough to get some oil in the heads) and then let it sit another minute or so whilst I put on the seatbelt, adjust my crotch, mirrors, seat, fiddle with the stereo, climate control etc.

Then it gets babied for a few miles until the gearbox is up to temperature. I generally take the view that if the gearbox is up to temp, the engine is going to be too.

Here's the real rub - If you're concerned about preserving the life of your engine as much as the nice folks above, start changing your oil every 2000 miles. If it comes out black, you need to ask yourself why. If it comes out looking new - you're probably changing it too often!

Fox, I'd suggest that your oil needed changing 6 months ago :D

[VR4WGN]

very interesting boys.. i like this sort of post...1 question then i hav eis why on (some of my older vr4's) when cold would it blow some smoke but fine when warm then? does this have anyhting to do with the Cold/Hot theory you talk about(oil flow)?

[Turbo_Steve]

Possibly. It's also possible that the pistons are cold and slapping about a bit in the bores. It's more likely it's rich as feck, though, knowing VR4s.

[jiggy007]

i basically just start her up....wait around 30 secs..then take off, i take it nice and easy till the "temp" is in the middle then, im good to go to do what ever....

cheers