Idling from cold.....

Doesn't warm up efficiently and it's running without a load. Best is to drive gently for first mile or two. They're poor engineering anyway,-pistons flying upwards, stopping dead and flying back down thousands of times a minute. Mr Wankel had the right idea. DaveK.

Also sprach "Tom Burton" :-

Mostly it's 'cos when the bores are cold fuel condenses on them and washes away the film of oil left behind by the rings. Clearly - this is a bad thing.

Also, the engine warms up slowly as does the exhaust so the insides of the exhaust are wet with acidic gunk for longer - again this is a bad thing.

Also - it uses a lot more fuel to warm up a car idling in the drive than it does to warm it up in the first few hundred yards of driving.

Also sprach "davek" :-

Actually - they don't "stop dead", they're decellerated nicely to a stop by the geometry of the crank arrangement. The acceleration from rest at TDC and BDC is similarly smooth of course.

Likewise with cams and followers - if designed and used properly their movement is smooth.

As far as I'm concerned, the best way to start a car when it's cold is to let it idle for a while until warm, ie. all the ice has melted off the windows and the cabin is warm, and the temp guage is up to normal operating level. The idea that you get moving as quickly as possible, so as not to burn more fossil fuel than you need, is environmentalist not mechanical. It's safer to drive a car that is fully warmed even though you may have burnt more fuel to do it. The oil pump works just as well at tickover as it does at road speeds, but having the engine tickover until warm is a lot better.

It generates a lot of cumbustion acids, tkaes forever to warm up, glazes the plugs up and possibly the bores.

Idle it for twenty or thirty seconds to make sure oil is getting to the top end then drive off gently. Don't thrash it until the oil is up to temperture - five minutes after the coolant is up to full temp is probably a sufficient margin.

You seem to be on your own with this view. It's also against the advice I've seen in any car or motorcycle handbook I've owned in the last 25 or so years.

Just sat idling the engine will warm up slower than if it was put to work. The longer it is running with a richer mixture the more it will wear (especially petrol engines).

I tend to let a very cold engine idle for about 15-20 seconds before pulling off just to make sure oil is flowing around all the engine components and to build up some pressure in the hydraulic tappets. I then drive gently (less than 3000rpm) until the temp. gauge has gone beyond the blue sector and the heater is pumping out hot air.

If you can afford it then a coolant heating system (e.g. Kenlowe Hotstart) will improve things for you and your engine. Or buy an old Rover 218/418 TDi - mine used to blow warm air out within half a mile of starting and was fully warmed up (according to the gauge) a mile later - about 4 minutes!

Darren

Yes. Because they bow to the environmentalists. I defy anyone to say they have wrecked their engine warming it up the way I do. I have done this with my bikes and cars when it it icy for 25 years.

The idea that you get moving as quickly as possible, so as not to burn more fossil fuel than you need, is environmentalist not mechanical.

The idea that you get moving as quickly as possible, so as not to burn more fossil fuel than you need, is environmentalist not mechanical.

In the late 70s? I doubt that the Environmentalists had any notable input.

The way this would wreck an engine would be accelerated wear of the top end (I'd guess) so you wouldn't easily be able to prove this unless you compared a sample of engines; one set treated this way and one another.

I still think you're wrong to maintain that this is 'better' on anything apart from the grounds of personal comfort.

So? How does that detract from the points raised above?

Snip.

No he (or she) isn't. All the stuff about condensation in bores etc is put out by oil companies selling their "special anti-condensation" oils. Once the engine has started and the oil light has gone out, all parts are getting lubricated, and any condensation which might have been in the bores, which let's be honest is an infinitesimal amount, is wiped off the bores with the first turn of the engine, and assuming the vehicle is in regular use, ie has not been left standing for yonks, there is sufficient oil remaining in various bearings etc to protect the engine.

Primary consideration before driving off on a cold morning, and that is surely what has prompted this thread, is that the vision should be clear. All else is secondary.

Steve

Stop saying that and ignoring all the other points.

I completely agree, it's a car and you are flesh it doesn't mind being cold! It's nice and warm inside the house with the central heating! Run out 10 minutes before you want to go, start her up, get the heater on full and go and have a cup of coffee while you watch the ice melt off the screen! It's not the kindest thing to do to the engine but it's going to take a lot of winters to kill it like this IMHO. At least in winter the engine IS under a load with the alternator powering all the electrical gizmos (heater seats, fan, rear screen de-mist, hell stick the lights on as well!). The thermostat allows the engine to heat up pretty quickly when cold anyway! Remember the car is meant to serve us :-)

Unless it's a diesel and it's under my bedroom window. In which case I'd give it about 2 days before it was dead.

John

Also sprach "Darren Jarvis" :-

I do the same with the diesel to make sure the turbo's got oil before I start making it spin wildly.

If the windscreen (and other windows, for that matter) are iced up on the outside and fogged up on the inside, just what other alternative have we got to warming up from idle anyway? You've got to be able to see out of the bloody things before you move off haven't you?

Mogweed.

Kettle of hot not boiling water sorts both if I am in a rush! I always put the wipers on to stop it freezing again!