PeachParts Mercedes-Benz Forum - One year old bad glow plug

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Quote:

Originally Posted by Brian Carlton (Post 3078937)

Removal of the plug to check heating pattern is the defacto standard.

However, it's a lot of work and isn't warranted unless you demand absolute performance in temperatures that are frequently below 0°F.

I've used the method with the ohmmeter for the last 12 years and have never failed to identify a bad plug. If the resistance is between .7 and 1 ohm, I let it go. If it's open or greater, I change it.

Fortunately, I have never encountered a plug that wouldn't perform but had proper resistance readings.

x2.

I am a newbie, so it is only in the last 5 years, not 12. If it had a 'dead short' then the fuse would either blow or the GP will become open circuit when the massive current went thru the next time. As for GP measurement, any run-of-the-mill cheapo would do to measure resistance.

Quote:

Originally Posted by ah-kay (Post 3078959)

I don't worry about dead short glow plugs, they are rare and obvious.

False OHM readings are common, I have at least 50 in my junk box that all OHM between 0.5 and 1.0, but are obvious junk when tested in the vice.
I never throw out glow plugs, even total trash, worst case the shell can be re-used to make a reamer or compression test adapter.

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