I got his car in, and tested the GP's with ohms... all but one read between 1.8 and 2 ohms... so I pulled them, to change them out. I replaced them with bosch and then took the plugs to some jumper cables, and they all heated up at the tip. orange, slowly, but they did all heat up at the tip...
the new plugs were all around .6 ohms...
why did the "bad" plugs heat up?
I was expecting them to heat wide, or not at all, but to see them heat up and at the tip surprised me.
they were slow to heat, around 6 seconds before glowing, and they never got yellow... only orange.
Hmmm
more fodder for the testing glow plug methods...

oh, they were all bocsh also... modern style tip.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!