When engines were super inefficient and fuel was cheap it made sense cos the car engine would only run under choke: would be very inefficient (even more so than normal) but with a thermostat idling would warm up the cyclinder head fairly quickly which in turn meant a warm inlet manifold and hence better fuel vapourisation and hence smoother running and less choke.
Chokes were of course manual in the days I refer to: pre 1980s and pre fuel injection.. all petrol.
Like most of motoring lore, it has been made obsolete by electronic fuel injection, low water content engines and greater efficiency (= less waste heat).
So basically for a modern engine it's a load of "cough" .. err rubbish...
madf
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Idling an engine when cold was even worse when chokes were manual etc because you had so much rich mixture washing the lube of the bores and ultimately diluting the oil. the same is the case to a lesser extent on modern F' Inj engines.
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There is another problem here: I find my Golf mists up badly if I drive off on a frosty morning (I live in open countryside)before the cabin and screen has warmed up. It makes no difference whether the aircon's on or off. So purely as a matter of common sense I don't drive off until the cabin's begun to warm up. I get a similar problem on both a Mercedes and a BMW so it not type specific.
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Cold idling is generally reckoned to be a bad thing. It's not very friendly to sleeping neighbours either.
I do recommend an engine preheater to those for whom cold starts and freezing passenger cabins are a persistent problem. I had a Kenlowe Hotstart (as recommended by HJ) fitted to my MB W126 yesterday, having had a very satisfactory experience with one in my W124 Coupé, in which it not only heats the water to 80° C but also provides a warm cabin from the outset and a distinct improvement in fuel consumption (about 7%). The more short journeys you have to do, the greater the percentage impact on fuel consumption. Fitting is certainly not a DIY job for someone with my limited skills, but probably is on for someone who does their own servicing and perhaps a bit more.
Preheaters aren't cheap, but as a long-term investment in a device that can be removed to a new car, I rate them highly. With the benefits to engine health, fuel consumption, cabin comfort, etc., I rate them more highly than air conditioning (I have cars with and without A/C).
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When I start up in cold mornings I switch off the aircon fan 9and hence aircon) until the engine warms up. All it does is circulate cold air and cool the engine:-)
madf
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It sounds like the general consensus is to avoid idling from cold if possible.
I probably didn't make it clear from the start that the main reason for me is to warm the cab to avoid the misting up scenario rather than 'warming the car up' like the way my old dad used to. My wife (who I love dearly...) has an infuriating habit of using the back of her sleeve to demist the windscreen leaving dirty great smears...
The preheater sounds like an idea but with global warming in the making may be unnecessary in few years.
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If you can get your car off the road, then run a 2KW fan heater on a timer. 20 mins max before you get in - lovely.
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If you can get your car off the road, then run a 2KW fan heater on a timer. 20 mins max before you get in - lovely.
Do you actually do this? I would have thought that using a 2 kW heater in a car would damage the interior trim.
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L\'escargot.
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I have done in the past but the last few years I have managed to clear the garage so the car's covered at night. I used one of those small fan heaters, the ones you sometimes see under desks in offices. May not be 2KW. If positioned carefully shouldn't cause a problem, mine never did. I used to position it in the boot with the parcel shelf down.
You could try one of those small 'black heat' cupboard heaters, they are very low consumption but you would probably need to keep it on all night to have the desired effect.
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I find that my fan heater on the rear parcel shelf facing forwards tends to over heat trip when set to 2kW, but 1kW works very nicely.
When positioned centrally on the parcel shelf there is an unobstructed path to the windscreen, which clears from the top down as the inside of the car warms up.
So far, in serveral years of using this method, I've had no damaged trim.
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There is another problem here: I find my Golf mists up badly if I drive off on a frosty morning (I live in open countryside)before the cabin and screen has warmed up. It makes no difference whether the aircon's on or off.
Using aircon in cold/cool weather can be counter-productive regarding keeping the screen clear of mist. Using aircon (at any time) causes moisture to collect in the aircon unit and not all of this moisture drains away. The residual moisture will come into the car via the demist nozzles (and the other heater air outlets) if only the heater is in use and this can actually cause misting when the screen is cold. Eventually the residual moisture will dry out but until it does I find it annoying. The only way I can prevent it happening in my car when the weather is cool/cold is not to use aircon. I use it very occasionally in cold weather purely to keep the seals etc functioning correctly.
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L\'escargot.
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L'escargot.
That's the idea behind the aircon- knock the water out of the air to make the incomming air more efficient at drying the screen.
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my 2p worth....
its bad for the engine , wastes fuel blah blah...BUT if you need to warm the engine to be able to have clear windows and be able to drive safley then id say carry on doing it, but in normal conditions just start and drive away
thats one thing that winds me up....seeing folk driving along with a small patch off ice cleared off and not being able to see some poor mug like me on the side of the road
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This morning at 2 deg C and ived over screen. Aircon on demist, heat on high, auxiliary diesel heater would have been on screen cleared in less than 5 minutes. As long as it took me to clear the rest of the windows. I've never had problems with residual moisture using aircon during winter.
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This morning at 2 deg C and ived over screen. Aircon on demist, heat on high, auxiliary diesel heater would have been on screen cleared in less than 5 minutes. As long as it took me to clear the rest of the windows. I've never had problems with residual moisture using aircon during winter.
Your aircon may not have been doing anything - it doesn't usually work below about 4C to stop the evaporator from freezing.
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Yup, couldn't agree more with steveo3002. Saw one of those several years ago: a 4x4 in motion with a letterbox patch clear at the foot of the driver's section of an otherwise frosted windscreen -- sheer criminal lunacy.
Global warming makes preheaters redundant? Nah, don't think so somehow. Have you noticed how this month was being set up to be the warmest December since records began, etc., etc., . . . until the anticyclone settled in about three days ago and now looks likely to see us through until Xmas day and beyond. Spray some healthy scepticism on every global-warming announcement.
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>> L'escargot. >> That's the idea behind the aircon- knock the water out of the air to make the incomming air more efficient at drying the screen.
But as soon as I turn off the aircon the residual moisture comes into the car and the screen mists up! Not only that, but the aircon has cooled the screen which makes misting even more of a problem.
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L\'escargot.
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I do exactly the same as L'escargot.
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SFAIK the approved way to warm up a car, assuming that it is driveable in respect of clear defrosted windows etc, is to get into it and drive it away, gently.
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But then I guess no-one really keeps their cars for years on end, after 3 years or so it'll be swapped out for a later model, so it won't matter whether you warm it on idle or not....unless it gets nicked whilst you are leaving it idling.
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But then I guess no-one really keeps their cars for years on end, after 3 years or so it'll be swapped out for a later model
Speak for yourself! ;o)
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Yes, speak for your self! I only buy them after 3 years old.
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" 4x4 in motion with a letterbox patch clear at the foot of the driver's section of an otherwise frosted windscreen -- sheer criminal lunacy."
These are known as Tank Commanders, and are better despatched to Salisbury Plain for a spot of remedial driving instruction.
Some cars, Ovlovs and Mercs for example, can be specified with internal pre-heaters initiated by a preset timing switch. You step out of the front door straight into a safe, warm, lit car, and drive off. Now that is what I called civilized. Mind you, I can do without the Scandanavian winters - twilight by day and 18 hour nights. I'd need that pre-heater just to get me out of bed...
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An offence to "quit" your car on a road with the engine runnong or the handbrake not set.
Also highly foolish to leave a car ticking over on a highway as it makes it too easy to be nicked. So don't do it.
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Also highly foolish to leave a car ticking over on a highway as it makes it too easy to be nicked. So don't do it.
...especially as your insurance is unlikely to pay out.
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Also highly foolish to leave a car ticking over on a highway as it makes it too easy to be nicked. So don't do it.
Yep, my car doors won't lock from the outside if the engine is running.
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L\'escargot.
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You can buy a device by Hella which keeps the engine running without the keys in the ignition, the emergency services use them, as do some trades who need the engine running for power take off etc....
The one I saw was about £100 and you pressed a small button before removing the keys as normal, and the engine would continue to run.
You could wire up to six wires to circuits such as brake light, interior lights, reversing lights, handbrake light, central locking etc... so that if the vehicle was tampered with the engine would stop and certainly couldn't be driven. Would be nice, but looked a PITA to wire in.
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Pugugly quote: "An offence to "quit" your car on a road with the engine runnong or the handbrake not set.
Also highly foolish to leave a car ticking over on a highway as it makes it too easy to be nicked. So don't do it."
Don't know if this was intended as a response to my posts, but since it followed one, just FYI, I and my cars live 400 metres from the public road, on a privately owned farm.
The pre-heater etc referred to does not over-ride the manufacturer's security.
But maybe your stern warnings were aimed elsewhere? Are you a policeman?
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See this ruling from the Insurance Ombudsman regarding four complaints of rejected claims against insurance companies. In each case the driver was close by, shutting a door or loading something into the car.
"complaints upheld
We considered the four complaints above were valid. We interpreted these exclusions as removing theft cover only when the car driver has clearly gone away from the vehicle. This applies regardless of whether the exclusion referred to leaving the vehicle ?unattended? or simply stated there was no theft cover if the keys had been ?left?. This interpretation required evidence that the driver had either gone a significant distance from the vehicle or had left it for an extended period. It was not sufficient for the driver merely to have turned his back or gone inside his home briefly. "
Note the words "significant distance from the car" and "extended period".
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Shropshire this morning is white over with frost and wife was out before 7.00 -- she went to car five minutes before she wanted to go and started her Yaris up - heater on full and heated rear screen on - went out to a fully defrosted car and off she went - Now her old Clio was a nightmare - half an hour of idling produced negligable heat and lot's of scraping was required and it was only after about 10 miles was the heater good enough to defrost windows properly - this wasn't one Clio but also a facelifted model as well - when we now buy cars we make sure when we look at them they are cold and time the warm up till air is hot. Over five minutes forget it.
My Mazda is also a quick warmer.
Dave
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I don't think my 2005 TDCi Mondeo would ever get to "normal" temperature if I just left it ticking over at low ambient temperatures. I was sat in traffic for 15 minutes one night last week on my way home from work and the gauge hardly moved of the bottom stop, heater was working ok though. Unlike my previous one, the V6 petrol, which would get to "normal" temp in about 5 minutes whether I was idling or driving.
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There is another problem here: I find my Golf mists up badly if I drive off on a frosty morning (I live in open countryside)before the cabin and screen has warmed up.
probably coz the car is damp inside. if you can stop the water getting in, it won't mist up anywhere near as much
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Funny thing is, it's clearing much quicker now. Must be that it was left unused for a few weeks and has dried out inside now.
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