Bad glow plug(s)
 

I am getting the glow light on the dash after starting car and then it goes out. My understanding is that this indicates one of more glow plugs is bad?

I pulled the glow plug harness from the relay and tested each port with OHM meter.

Plugs #1-5 registered 1 OHM.

Port #6 registered nothing. There is no continuity.

I confirmed the glow plug relay was putting out 12V at each of the pins and it makes a clicking sound.

Does this mean this #6 is a bad glow plug? If so, should I change the others at same time? I've read about the horror stories of replacing these plugs and am going to have a mercedes tech with experience do it.

Vehicle now has 171k miles (just updated signature).

Bad glow plug on #6.

If you're having someone else do the work (as I would do), you might consider letting it go until another plug or two goes bad. It will certainly start reliably with five working plugs.

I am having rough starts....about 20-30 seconds of missing and white smoke then she goes smooth.

Is it possible other plugs are bad even though they register 1 OHM?

Shouldn't # 6 at least show a completed circuit? I tested the harness before installing and wires were good.

Classic symptoms of a bad glow plug.

Of course it should. The fact that it doesn't is not insignificant.

Can you get a probe on the #6 plug connector and test continuity back to the glow relay connector?

Sixto
87 300D

I'll have to remove air intake to get to glow plug six connector. I tested it before I installed the wiring harness for continuity and it was fine.