>>Warming up the car in the mornings before driving off

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COMBOM

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Hi all,

I normally start the car in the morning and leave it running for about 10 minutes before driving off. today I heard from someone it is bad for the engine and you should not do it. is this true, what damage can it do in just 10 minutes? and why?
 
It is very bad for the engine. On Tickover it takes a lot longer to get the engine warmed up. When an engine is warm the pistons shape changes as they expand and fill the chambers properly.

Upto this point when cold you have a lot of moisture and acids caused by combustion flowing around the engine which quickly builds up. The catalyst also gets hammered when it is cold.

Driving a car puts a load on the engine and warms it up much more quickly. There are other reasons but these I think are the main ones.;)
 
i have no choice, if i don't let her run for a few minutes then my truck will die on me everytime i let off the gas. thinking of getting a block heater to solve that. keep the engine warm 24/7
 
Really?
I thought the only reason it warned up quicker is the pistons are moving much faster and the friction causes it to heat. I thought that the oil should warm up so it can get into the gaps of the pistons so it does not cause wear by friction.
tell me would it do damage to a pasat at 45000 miles that is warmed up for no longer than 10 minutes?? not a long time really.
 
Holdign the revs at 2000 will help - at idle it really is not going to do any good there is just not enough going on in the engine to properly warm it up.

At times we all let our cars idle but I strongly recommend it is avoided.

Regular oil changes every 6 months should help a bit.
 
Thanks Waynne for your advice on this.
Just to clear things up, is there a problem, will it cause damage to idle for 10 minutes?
 
It speeds up the engine wear. It will not break it as such but you are reducing the lifespan/reliability of the engine.

IMHO you are also likely to need to replace the catalyst in around 50-70% of its expected life span and this will be a similar story for other engine components.
 
I was talking to engine specialists and even called audi & VW but they say yes its true but 10 minutes is not an issue, infact you are better to warm it for 3 minutes than just get in and drive after a few seconds after startup as it allows the oil to circulate and get into tight areas. I was told the Passat diesal has high compresstion and that the combustion chamber starts to warm as soon as you unlock the door so by the time you start it, it will be warm and there should be no problem with moisture and acids caused by combustion flowing around the engine. is this true
 
COMBOM said:
I was told the Passat diesal has high compresstion and that the combustion chamber starts to warm as soon as you unlock the door so by the time you start it, it will be warm and there should be no problem with moisture and acids caused by combustion flowing around the engine. is this true
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would like to know how they do this ?
other than the glow plugs coming on when you unlock the doors i cant see how the enigne would warm up quickly as theres nothing to really make a lot off heat. yes the plugs produce a bit of heat but not enough for it to work its way throughout the engine

i do know that when open my drivers door you can hear the fuel pump sounding like its priming itself so maybe this is when the plugs come on.

all diesels generally have high compression due to the nature of diesel.
 
ever wander why the revs are high when its cold???

its because, thats the engienes normal procedure to warm itself up, and when i say this i mean, to push liquids, especially oil around itself

the revs are higher to push oil up from the sump

now, this is a fact ask any mechanic, manufactor
the first 10 mins in the morning, is when most of the wear and tear of an engiene occurs
(thats why i use GTX Magnatec)

so, when you put more revs on to a car, than whats needed, its bad for the engiene
and when i say whats needed, i mean,
first thing in the morning, your cars revs will be just under 2000 rpm
when everything is lubricated and curcuilated, the revs drop back down to normal,
jusy under 1000 rpm

this will happen before your car reaches its normal running tempeture,
and thats when you should then drive off

ps. you still shouldnt drive hard until the car does reach its normal tempeture
from there on, its totally ok

so, its best to leave your car sit until the revs are at 800 rom or there abouts

this is for petrol, i dont know about diesel, as i never had 1
 
when i start mine up in the morning, i push the clutch down before i start the car, not sure why but always been told to do it, then i drive the car very carfully to work until temp gage goes up.
 
but!!! really cool thing.....my fathers car , C-Class Benz, 08 plate (lucky buger) when he opens the car from his key fob from the kitchen, it starts warming up from that point, so the time hes finished his cuppa the cars temp gage is up by 1/4.
 
dont know why you put the clutch in,
but your definatly doing the right thing by not screwing it first thing
 
Hammy said:
but!!! really cool thing.....my fathers car , C-Class Benz, 08 plate (lucky buger) when he opens the car from his key fob from the kitchen, it starts warming up from that point, so the time hes finished his cuppa the cars temp gage is up by 1/4.
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is that the water or oil guage ?

my water guage doesnt take long to heat up couple of mins and its up to temp but the oil takes longer normally 5-10 mins before its up to 90 degrees
 
pgarner said:
is that the water or oil guage ?

my water guage doesnt take long to heat up couple of mins and its up to temp but the oil takes longer normally 5-10 mins before its up to 90 degrees
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hi pg,
i was on about petrol cars in that post
yours is a diesel so it could be totaly different

the only thing i know about a deisel car is that it has a light on the dashboard telling you when the plugs are warmed, then you can start it

im pretty clueless to any other thing about them
 
I think I read (here on torquecars actually!) that keeping the clutch down when u start the car puts less strain on the battery or something..

Hi, I'm the new guy :)
 
Thats what i've heard to and yes I think that was on here as well. Hello VWFTW, it might be wrth posting a hello in the greetings forum otherwise youll get lost in this thread.
 
The starter motor will not have to turn the gearbox over if the clutch is depressed. Even in Netral there is still some extra drag. Plus if someone has left it in gear it won't jump forwards.
 
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