You should be able to hear it working within a couple of minutes. It makes a kind of sizzling sound. If it is quiet outside you can hear it just standing next to the car.

-Jim

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1995 S350D, Green with black leather interior.
Bought January 2008 w/ 233,xxx miles.
I did 22,000 miles during the first year of ownership.

I just went out to hear it- I can hear it if I lean over the engine and put my head in front of the air cleaner assembly. From anywhere else I can't hear anything.

You can hear yours from outside the car? Hood up or down?

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Andrew

1989 Volvo 745- 202K

Buy a "Kill a watt" and you can plug the block heater into it so you can actually see if the block heater is working.

http://www.amazon.com/P3-International-Kill-Electricity-Monitor/dp/B00009MDBU

I use mine all the time to make sure things like that are actually working.

I have never expected the block heater to get the engine hot. I do find that if it has snowed, there will be snow on the trunk and roof, but it will be melted on the hood. (My hood does not have a liner in it. It came from Atlanta and originally Texas, and I understand that in a hot climate they often take them out to help the engine dissapate heat better.) I would think that the valve cover is so far away from the heater, it would not keep warm.

My car starts fine with or without the block heater running. When I have run the heater, the temp guage starts out just above the bottom line, and when I turn on the heat, the air is not ice cold but just barely warm. Once driving, the car comes up to temperature much more quickly.

I did some calculations based on a 400W heater and based on my cost of around 11 cents per KWh, I figure I am paying around 4 cents an hour to run the heater.

My biggest problem is that at work, I plug into a GFI protected outet on a light pole, and the GFI is very sensitive. It is often tripped off when I plug in and I need to go and reset the breaker.

The bottom line is that if the block heater was getting your engine hot, it would be much more expensive to operate.

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85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

FWIW... i found this on another forum... that i have migrated to ...
http://www.lostkjs.com/forum/phpBB2/viewtopic.php?t=28852&sid=556184e68cade3708f71498d463e6ad9

said that his engine only got to 79*F from an outside temp of 18*F

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-Trevor

OBK #12
1980 300SD 333,XXX miles - Totaled
1986 Mazda RX-7 212,XXX miles - impounded and auctioned off
2005 Jeep Liberty CRD Limited 33,000- SEGR, Provent, Fumoto

Will a block heater damage the engine if left plugged in for an extended amount of time? I see alot of people saying "4 hours". I would like to plug mine in before I go to sleep then unplug before driving to work in the morning.

I've done that no problems... i would just check the coolant level more often.

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-Trevor

OBK #12
1980 300SD 333,XXX miles - Totaled
1986 Mazda RX-7 212,XXX miles - impounded and auctioned off
2005 Jeep Liberty CRD Limited 33,000- SEGR, Provent, Fumoto

........I suppose. If it is below freezing, I am sure you could leave it plugged in for weeks. When I was a kid (here in western Canada) and we used Fahrenheit, we usually didn't plug in our (gas) cars till -15 or -20 F but left them plugged in for days. power was cheap. And really it still is.

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Thanx,
Alberta Luthier
1983 300CD ('Stinky')155k miles, 2.47 diff, EGR removed, AAZ injectors with 265 nozzles from Sean,and vogtland lowering springs.
1984 300SD ('Old Blue')150k Klicks from Japan originally, came with rear head rests, no sunroof and never had an EGR

The block heater cord on both my MBs need replacing. The cords have lost their insulation, etc.

Is this the correct cord to replace with?

The package they came in have Zerostart written on them:

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=2AR1EO21I2AR1F7F2D&year=1983&make=MB&model=300-DT-001&category=All&part=Block+Heater+Cord

__________________
JWJ
1983 MB 300D - > 430,000 miles - Deep Blue - Bilstein Comforts - 0-60 in 24 seconds - 27MPG
1985 MB 300TD (wagon) - > 275,000 miles - Manila Beige - Thule rack - 0-60 in 18 seconds - 22 - 25MPG
Biodiesel, Mobil Delvac 1, and Viton fuel lines!