I recently changed all 6 glow plugs on my OM642 at 202,000 miles.
The glow plug light had started coming back on for about a minute after starting.
The plugs were last changed at 110,000 miles ... about 10 years ago.
The car was starting OK, but was a little bit lumpy for the first minute or two.
I was a little bit unsure how to go about it, but, with the help of past threads on the Forum, and a couple of U-Tube vids, I decided to have a go.
The first question I had was - How to get at them ?
I checked the first two with a meter - Found them to be OK - Very low resistance.
To get at the rest, I was obviously going to have to remove the batwing - A job to be undertaken with care, as it's easily damaged.
At this point I decided to change all six.
The job needs care and patience.
As said above - It's easy to snap these things if you are a bit too enthusiastic.
Use plenty of best-quality penetrating oil - At least two applications with the engine hot.
Then do the job with the engine hot.
I found one plug had gone high-resistance.
I'm glad I changed them all.
When re-fitting I coated the threads, stems and seats with Rocol "Never-Seize".
Keep the grease off the glow plug ends.
Use a torque wrench to refit the plugs.
The job was a success - No disasters.
I changed the big red seal between the batwing and the turbo intake.
The seal was in poor condition.
Again - Worth that little bit of extra expense and effort.
I must admit to being a bit wary of the job.
But - With enough care, it was less-scary than I feared.
Filled my storage shed up with what looked like steam - unburnt atomised diesel puffing out of the exhaust
