Secure Demisting/de-icing

December 1, 2009

After a few weeks of wet and windy weather, for me it's been a return to scraping ice off the car this week.

If it's really cold I need to warm the windscreen up a bit before I can safely set off so I run the engine to demist the car and to make frost and ice easier to shift (bad news for the mpg, I know!). I've found that the car can be locked while still running by using the mechanical key that sits inside the keyfob (leaving the keyfob somewhere in the car). I think I read about this tip on Priuschat but thought I'd give it a go on my Gen III as I believe they have a different locking setup in the U.S. Where I live, I'm not really concerned about someone driving off in my car but I know it can happen and insurance may not provide cover if the car is stolen while unlocked with the key in the ignition.

It's the first time I've tried using the mechanical key (I really like the touch sensitive unlocking - no more scrabbling for keys before I get in :) )

I think Gen II cars behave the same way?

Apologies if this has been discussed previously- a quick search didn't pick up anything on this topic.

December 1, 2009

Hi is it such a good idea to leave a car running unattended especially as it will only run for a few minutes before turning off

much better to drive off as soon as possible, you could put rain X on screen it helps to keep screen clear when weather not to harsh

December 1, 2009

Hi is it such a good idea to leave a car running unattended especially as it will only run for a few minutes before turning off
much better to drive off as soon as possible, you could put rain X on screen it helps to keep screen clear when weather not to harsh

I think it is almost a necessity in Scotland (even if nowhere else) at this time of year (especially as I leave at 0630 for work each day). I have found that by setting the demister on full - it keeps the engine runnning enough to clear the ice.

December 2, 2009

Hi is it such a good idea to leave a car running unattended especially as it will only run for a few minutes before turning off
much better to drive off as soon as possible, you could put rain X on screen it helps to keep screen clear when weather not to harsh

I agree that it is much better to set off as soon as possible but in my experience if it is cold enough for thick frost/ice to form it is better to warm the windscreen a little first. My preferred technique is to start the engine with demist on then go and get some warm water to pour on the windows. By the time I've done this the ice has usually thawed enough to be removed by a rubber blade (I prefer to avoid scraping and potentially scratching the windscreen, and using water is almost as quick as the ice comes off very fast once it's thawed enough). It takes me about 5 minutes or so, so the engine is always running but in any case I trust my Prius to decide if it can carry on delivering hot air with the engine off :)

I have set off immediately on a very cold day in the past (in a different car) and had some ice forming on the inside of the windscreen so had to stop again which defeated the whole object of the exercise. Also if it is cold enough, any water poured on the (cold) car will refreeze before I can clear it, but this doesn't happen all that often, even in Aberdeen.

Anyway, I like the locking option - I don't think I could do it on my last car without a second key.

The rain repellent sounds like a good idea though: I imagine it would reduce the time it takes to clear any ice plus I do sometimes have trouble seeing out of the side windows in wet weather.

P.S. I don't envy you scraping ice at 06.30 JaysPrius! I leave about an hour later but it's still dark. I guess it will be mid Feb/March before it starts getting light again - it seems a long way off at the moment :(

December 2, 2009

I tried Rain-X a long time ago, on one of my previous cars, and I really hated it because when I did need to use the wipers they would judder and skip across the windscreen which resulted in it leaving sections uncleared and there was also a horrible noise as it skipped and then caught. I was happy when the treatment wore off.