I'm going to swap out my glow plugs this weekend and I'm going to expand my tool collection to do it.

Once I remove the rail I can slip a closed end wrench down to the glow plug nut, right? Is it best I purchase offset or straight wrenches?

This is for my 1981 300TD with a 617.952 motor.

Been there, done that! Changing glow plugs on a four cylinder is a piece of cake, but on the five cylinder it's murder without removing the injection line spider web.

Just use a 17MM open end wrench and remove the lines between the pump and the injectors, and set them in a clean place out of the way. Then, change your glow plugs and reinstall the spider web.

Once the injector lines are in place and all tightened down, loosen all the connectors at the injectors about 3/4 of a turn. Have someone turn the starter while you watch for fuel from the loosened connections. As soon as you see fuel dribbling from one or two of them tell the ignition key operator to stop cranking and then tighten the ones where you see fuel. Then have them try again to start until you see fuel dribbling from one or more of the other injector connectors. If the engine starts, simply tighten the remaining connections and go on your way.

Good luck,

get a flat 12mm gearwrench. it has to be flipped to change "on or off". the tool goes on once and crank away. the offset gear wrenches need too much clearance. i think it could be done without removing the fuel lines. good luck, chuck.

Yes indeed, it can be done without removing the fuel lines. I've done it both ways. For me it's much easier and quicker to remove the fuel lines.

Good luck,