engine warm up

I assume we're talking about this



You'll note it says efficency not wear. It also makes no reference to ambient conditions.

Also Mike, the former doesn't suggest using more fuel as by driving off straight away you are running the engine under load whilst still in a rich state.
Edited by: Golden

 

"Always use the right fuel for your car. All Shell Advanced Fuels contain detergent additives to prevent the build-up of sticky black carbon in your engine. Without this protection engines can lose performance and use more petrol as well as giving off more exhaust emissions.---"
tip for the motorist, don't they mean plug for Shell!!

 

I think mr Trendy Tramp says different Golden. And knowing what he does for a living I'm inclined to believe him. hope he spots this thread and sheds some light on it!

 

what does he do.....?Doesnt work for shell??!!!!

 

I beleive whatever TT says.

 

he's something to do with designing new engines

 

my understanding is its better to drive off and not cane it until its warmed up.

can understand what golden says about short journeys though, perhaps if you know youre only going round the corner then 5 mins at idle is a good idea, but if its a longer journey then driving off straight away is better?

personally I try to walk instead of driving for 5 mins, usually find its quicker by the time you've got the car out, warmed it up, parked it and walked from there to where youre going, when its 5 mins journey.

 

ash f**k it, just rag the engine, somethign else will explode leaving it in tatters before it wears out

The M5 manuel says it should not be left to idle cold, driven but kept below the moving yellow lights.

 

Another reason they say to drive it of straight away is to get the catalytic converter (if you have one) warmed up as quick as possible as they don't work well cold.
Edited by: G60JAY

 

Golden is right in that letting it idle will not do any real harm.

However, the best method to use is driving off at very light throttle. Alternatively you could use light throttle whilst the vehicle is stationary and parked up - may help warm-up even more actually as you've got stationary air under the bonnet.

Think about how most of the oil is circulated around the bearings by hydrodynamic lubrication - at idle some engines can struggle to fully circulate oil around these bearings due to insufficient rotational speed.

Then think about oil pressure as well - at idle oil pressure is low so again the engine struggles to lube itself up fully.

So in fact everyone is right in there own way, as long as you don't tear up the road from cold you'll be fine; Modern engines are surprisingly resilient.

Now go away and leave me alone

tt

 

I think all this is to lower emisions and enviromental stuff. I thought starting and stopping your cars is not good so why do they recomend doing it while sitting in traffic.

 

the reason vw have always stated in the manuals to drive straight away is purely for enviromental reasons.
well thats what i was told anyway.

 

I would think about it if I had a clue what you were on about.

 

WHAT AINT NO COUNTRY IVE EVER EHARD OF, DO THEY SPEAK ENGLISH
IN WHAT?

 

I've got a question for Trendy Tramp.
My dad's Audi 90 quattro has got those dials in it that tell you the oil pressure. When starting from cold, the oil pressure read 5 bar at idle, this then drops to 1.5 bar when the engine has warmed up.
Why is that? surely 5 bar oil pressure is enough to lube the bearings?

 

Im no expert, but i think thats because the oil is thicker, and hence creates more pressure to pump it round.

mine reads 4 bar from cold. then 1-2 when warm.