Get a block heater for temperatures like this. Have it go on a couple hours before starting. Heating will not be a problem & your engine will last longer.

is it alright that i've been leaving my block heater on ALL night long? sometimes durations of 24 hours?

eric

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1995 E320 Sportline Wagon "Bernard"
black on black leather

http://i.imgur.com/BdZ7jM3.png

When I was in school, I would let my car warm up for about 5 minutes before driving. That was mainly because I hardly ever drove the thing. I now only let my car warm up for maybe 20 seconds, unless it is really cold, then I let it warm up for a minute or so.

Peyton300TD,
I believe most block heaters have some sort of cut-off when they reach a given temp. You may try using a timer & set it for only a couple of hours before starting to save electricity. In Texas I had a no-cost-to-me source of power so I plugged it in the night before. Never wore out the heater. On the 220D it was a great to get in the car on a cold morning and see the temp needle already off the peg before you even started it!

I don't think there is anything wrong with keeping the block heater plugged in all night but they only need an hour or so to bring the engine up to temp.

I have not needed to use a block heater for quite awhile (garages are wonderful) but when I did I would plug it in when I got up and after my shave, shower, breakfast and coffee the engine block was warm to the touch. I don't think they need to run for hours and hours....

Tim