Hey all! Was wondering if anyone knew how difficult installing a block heater on the w124 m103 motor is... I imagine you just lift it up, drain coolant unbolt the drain plug and bolt in the heater, sounds easy enough like most jobs up until you actually do it!

Any info/advice is greatly appreciated! Thanks!

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Removing the old plug in the block is the hardest part!

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Yeah I bet, being in there for twenty years with liquid passing by is probably is going to make it really hard, is there anything I can spray on it to give me some advantage? Do I just slowly work at it? I'd hate to break it!

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76 MG Midget
78 Datsun 280Z
86 Peugeot 505
01 Subaru Outback

“Owning a car is like owning a dog. Every now and then, it craps on the carpet — but it’s still your dog.” - Jeremy Clarkson

Cant help but wonder why you'd want a block heater in Texas?

As alluded to before it most likely will be very tight and you will need some serious tools to remove the plug. I've seen a 1/2" Snap-On ratchet bent like a pretzel with a 4ft cheater without removing the plug. I've heard horror stories of breaking the block during an attempt to remove the plug, though I've never actually seen it. Good luck.

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Hmmmmm that makes me not want to do this anymore haha.. Or maybe just do the ones that go between hoses... I really wanted the actual block heater though for a cleaner look rather than the hose one. That does look kinda funny doesn't it, I need to update my location I'm in California now but am thinking of Fairbanks, Alaska in two years for school and I've really always wanted one to be honest I was curious and the stealership quoted 670$! :/ But maybe that's why....

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76 MG Midget
78 Datsun 280Z
86 Peugeot 505
01 Subaru Outback

“Owning a car is like owning a dog. Every now and then, it craps on the carpet — but it’s still your dog.” - Jeremy Clarkson

My M103 has a block heater just behind the drain plug, kinda between and under 5 and 6 Ex. ports. Brass w/orange colored plug cover. See photo. This engine is in a w126, but that shouldn't matter should it. Just asking. I also removed block drain plug this summer with no problem whatsoever. Appears to be original (1988). Let us know if you proceed and how it turned out.

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Thanks for the picture! I think I'll go ahead and at least try it, what size socket did you use? and did you just slowly work at it or did it break free in a forceful turn? Just for reference the block heater goes in place of the drain plug right?

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76 MG Midget
78 Datsun 280Z
86 Peugeot 505
01 Subaru Outback

“Owning a car is like owning a dog. Every now and then, it craps on the carpet — but it’s still your dog.” - Jeremy Clarkson

As you can tell by the pic, I have a block heater in addition to a drain plug. Block heater is just to the left of drain plug. I don't know if a drain plug sized block heater is available. I was able to remove the "drain plug" by just working it back and forth carefully and oiling till removed. I've never had to replace the heater, but just looking at the size of it leads me to believe that it might be a little more difficult (but not impossible if done carefully with right tools) to remove it or a "plug" that might be in it's place. I hope this helps you, and good luck.....