I have a 1999 E300 and have been stuggling for days trying to get the old glow plugs out. Dealer recommended penetrating oil, which has not helped at all. What is, and where can I find, PB Blaster and Freeze-Off mentioned in above message? I live in San Diego. I am sure the threads in one glow plug are stripped as I can move it freely, but it will not come out.

Any help you can offer will be very much appreciated. I would love to be able to do this repair without removing the head if that is possible.