kchemers,

The plug you want is the one right above the front of starter which puts it's location about in the middle of the length of the engine.

I am familiar with the recessed hex size on the w123's, but am not sure if yours is exactly the same size or not. The w123's are a 19mm recessed hex. And fortunately a 3/4" hex bar of steel fits very nicely. We put the end of a 3" length of this bar into hex of plug and then got onto 3/4" hex bar with a 1/2" drive 3/4" (6 point) socket w/ breaker bar. Next, slipped a 5' long chumk of 1 1/4" pipe over breaker bar and put all of my 250 lbs onto end of pipe. Took 4 attempts before she finally broke loose: 3 of those with a cold block and the last after warming the block area around the plug with a torch.

It would be better to use a 3/4" drive socket and breaker bar if you have access to one, as we were flexing the snot out of our 1/2" drive.

On a non-turbo such as yours, I would recommend removing air cleaner and then exhaust manifold (provided your threaded studs are not rusted too bad). This makes the job a lot easier to do from the top w/ lots of room to work and lever clearance for pipe bar persuader.

I agree with it being very worthwhile in a cold climate. My wagon w/ nearly 300k on her starts and purrs nicely as long as she's plugged in (when below freezing). Aside from that aspect, I am sure it's better for the longevity of the engine to be starting her with thinner (warmed) oil, as opposed to heavy (cold) syrup.

I believe that our block heaters are 500-600 watts. I put them on an electronic timer that is set to come on 3 hours before I need to leave in the AM. I don't think one hour is enough to bring coolant up to temperature. I remember reading on this forum last year about this time that someone wrote it takes between 3-4 hours.

It sure is NICE to have instant heat blowing when you back out of the garage, though!!