The pre start trickle charge possibly just basically helps the battery to deliver more current when it is time to start. Kind of agitates the battery electroylite a little perhaps. Simular to pre warming a battery a little maybe. . THe slight top off charge does no harm either.

The pre start trickle charge possibly just basically helps the battery to deliver more current when it is time to start. Kind of agitates the battery electroylite a little perhaps.

A stone cold batery is way down in ability to deliver current compared to a warmer one.

My vehicle had a factory installed block heater. I purchased a cord on Amazon (see link below) and was able to install the cord from above. I tied off per other members suggestions and terminated the cord at the hatch under the bumper. Starting is much easier 45F or below. I connect to an external AC receptacle which has an internal switch in my house. I turn the switch on about 3 hours before I anticipate traveling.

I bought the cord on amazon for $14.49 and it was listed as a "Fleetguard Coolant Immersion Heater 6' Replacement cord 120V 251919":

Block heater power cord

It was a perfect fit for the factory plug and threads

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-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

A trickle charger left on a battery 24/7 will eventually dry out the electrolyte but 4 to 8 hours a day while the block heater is running on cold winter nights won't hurt the battery at all. And as others have posted, a warm and fully charged battery makes a great deal of difference in starting a diesel. In really cold climates (north of Winnipeg, say) the trickle charger helps keep the battery from freezing. This relatively rare situation typically cracks the plastic case and then the electrolyte leaks out all over the car's chassis.

Because my car has about 30 milliamps of "phantom load" (not really phantom because I know what it is and want it to be there) I have a trickle charger built in to the engine compartment and plug it into a timed outlet almost every night. The charger runs for only two hours but that's enough to keep the load from gradually discharging the battery, especially as this car isn't driven every day. [10 milliamps of discharge current is generally considered the safe limit.]

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I installed one in our 85 about 2003, they really do help to get things up to operating temp when cold. I had a shop do it after looking at the difficulty it would have been for me at the time. this was before I discovered the Forum. on an older engine, I still might pay some one to do it.

When I purchased the Metric Motor, I had them install one. they threw it in with the price of the engine. "That was easy".

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Seems that every year I've belonged to this forum, the subject comes up. I printed out previous threads, and brought an after-market block heater (plaices into the radiator hose) to the mechanic recommended to me in the Fargo, ND area that I found myself and car located at for the upcoming winter. After calling AAA twice in one week, I was determined to block heat my engine. I showed the mechanics what other MBZ owners said about the installation. They did not believe that even in a car as old as mine, they would need to use a torch and get the bolt red-hot to remove it. They insisted on installing an OEM block heater, which was fine with me, as long as they gave me a written estimate of the work. They were not happy to see me the next day. Seems that even with four lumberjack swedes hanging off a cheater bar with the car on the rack . . . they could not break that bolt loose (guess they never heard of "zincing." Hey . . . but what do I know . . . am just a woman and a dumb truck-driver . . . LOL.

Unless you have a torch to loosen that bolt, take it to a mechanic and have them install it, and warn them to get the torch out to START the job. ROFL

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1983 300D, the "Avocado"
1976 240D, 4-spd the "Pumpkin", SOLD to Pierre
1984 190D, 2.2L, 5-spd, my intro to MBZ diesels, crashed into in 2002

BTW, mine block heater was a life-saver, literally. Gave longer life to my glow plugs and battery, and the car had no trouble starting up in the -40 deg. F weather, if it had been plugged in overnight.

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1983 300D, the "Avocado"
1976 240D, 4-spd the "Pumpkin", SOLD to Pierre
1984 190D, 2.2L, 5-spd, my intro to MBZ diesels, crashed into in 2002

X2

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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

here's my winter prep thread from a while back.

overkill to the extreme.. but it was fun. works great.

Ultimate Artic MB300SD. Pictures!

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1985 300SD
2001 Toyota Tundra - soon to be replaced with diesel truck
2006 Honda CRV

My understanding is alot of the name brand("Battery Tender" for example) chargers are considered smart chargers, which charges untill the battery is full then switches into a monitor mode only charging if it drops again.
I have a little Battery Tender for the motorcycles. I use it on the truck and the Mercedes if i let them sit. Wiring one into the heater plug is a great idea!! I don't have the experiance with brutal cold like you guys up north but seems like a awesome idea! And these darn diesel batteries are not cheap!!!

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2006 Jetta TDI DSG 320k miles
1997 Ford F150 325k miles 4.2L V6 "Work Truck"
2008 Tundra 225k miles 5.7L
1982 240D.....sold
1984 300D...Totaled OUCH!
1985 300D Turbo 222k miles "Dos" sold to 79Mercy
1986 300SDL 98K miles "The Beater"....sold
1987 190E 2.3 16v Euro spec 115K miles....sold

My 240 is.one of those that did not have a factory block heater. I didn't want to take the chance with the potential block issues and a huge lack time. I installed a Katz k500 hose heater. So.far it is a big difference in how it starts. Not quite like it Is 80 degs, but one glow cycle and she fires up.

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1983 Black Mercedes 240d rescued from a field in Pecos NM.
Kids named it Helga Die Benz.
Edgewood NM Territory

it'd be nice if the pictures were still in the thread...
any chance you could upload them to the PP server?

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Webasto_123_diagram

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My occupational hazard bein'
my occupation's just not around...
1980 300SD
1980 300SD

I'll try to grab a few tomorrow morning.

I'm gonna sell the car in the spring. but I'm gonna pull the espar first.

JP

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1985 300SD
2001 Toyota Tundra - soon to be replaced with diesel truck
2006 Honda CRV