I'm not sure how easy it is to find a 19mm allen wrench, but a 3/4" allen wrench works just fine. I consider myself a pretty decent shade tree mechanic, and this job isn't especially easy. Don't even consider it if you cannot get the car up off the ground safely. I used a friend's lift to get the car up nice and high, pulled the starter (a challenge, but not too maddening), and then went after the plug in the block heater hole. We ended up breaking a couple of 1/2" drive accessories before getting a standard "L" shaped 3/4 inch allen and about a 6 foot pipe. Both of us were putting as much force as we could muster on the pipe before the plug finally broke loose. The block heater went in very easily, and I had the starter rebuilt while it was out (my buddy's dad runs a starter/alternator shop).

This job is well worth the effort once it's done. However, it will be an exercise in frustration if you aren't set up to do it right. You've got to be "In it to win it" to make sure the job gets done.

SteveM.

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'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner