So, I've got an 84 300 DT with the block heater. Question is, how do I use it? The plug has a "female" end to it, but anything I plug in the wall has the male end in the wall and a female end to connect to things. So, how do you connect it? Are adapters readily available? After its connected, how long do you leave it "on". Sorry to ask such a dumb question. I've had this car for 3 years, but this will be the first daily driven winter. After the first freeze I can already sense the hesitation! Thanks in advance.

__________________
1984 300D turbo, 250K
1971 MGBGT, 101K
2007 VW Jetta, 4K

That's strange. My block heater is factory and is male... You can buy either buy two male ends and make a small adapter or by a dedicated cord and cut the female end off and replace with a male. Any hardware store would sell the ends.

edit: Forgot to answer your other questions. Depending on how cold it is, it can take a few hours to get to temp.. I only use mine on really cold days (and here that means both of them). I use an outdoor rated timer to switch it on 2 hours early. It's nice to have heat from the getgo.

__________________
1982 Mercedes-Benz 300CD
1982 Mercedes-Benz 240D - stick

It's not possible to have a block heater cord with a female end. They are not made that way. You'd be plugging in a live male end each time you use the cord and, sooner or later, you'll kill yourself.

Remove cord, toss in trash, and purchase a proper block heater cord from this site.

The unit can run for about 3 hours and raise the block temperature sufficiently for a normal start. Most folks use a timer of some sort.

The correct heater and cord should look something like this:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ41X50KGAB2&year=1984&make=MB&model=300-DT-001&category=All&part=Block+Heater+Kit

I'm betting that if you look closely, someone has either replaced the original male end or there is already a pigtail there connected to the original male cord end. On my 77, there was a pretty short heater cord, plugged into another short cord under the hood which wound its way out thru the grill so it was accessible wihtout opening the hood.

Brian is right. One easy way to avoid having to worry about whether your diesel will start is to routinely use a hot male end. Your concerns will surely turn to other matters than whether your car will start.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Engine Heater ideas
Engine BLOCK Heater ideas







Have a great day.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

How cold does it get where you live? I have park my car over night in some pretty cold locations and never had trouble starting without a block heater.

Just because you can start a 617 without a block heater doesn't mean that you should do it.

Why not? What are the negative consequenses? I'm not trying to be confontational I just never thought about it.

More wear on the cylinder walls form cold metal/oil, and incomplete combustion letting raw fuel into the oil.

Starter health is important to your diesel.
http://www.peachparts.com/shopforum/diesel-discussion/107318-starter-health-important-your-diesel-post739798.html

Battery selection / Charging System / jump starting / cold weather battery issues
http://www.peachparts.com/shopforum/diesel-discussion/141516-battery-selection-charging-system-jump-starting-cold-weather-battery-issues-post1058189.html

Battery for your Diesel
Battery for your Diesel

Asked and answered.

If you've got a block heater and can alleviate some of the burden on the starter and the very poor oil flow from conventional oil, why not take advantage of it................!