According to the service manual, vehicles with the afterglow feature use different glow plugs. Note that the length of the glow tube is not always the same.

See the attached images for more information! They show the part #s for afterglow-rated glow plugs.

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1989 250TD Wagon 5-speed, 160,000mi ::: Dark gray metallic / black cloth
1984 190D-2.2 5-speed, 287,000mi ::: Silver-blue metallic / black MB-tex ::: SOLD

So with all the life shortening of the GP, is it really worth it?

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

I turn the ignition (glow plugs) on for 30 seconds and then start the car. If it runs rough, I turn it off. Ignition back on for 30 more seconds and then start again. This always works - even on 15 degree mornings.

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'87 300D 183K
'06 E320 CDI 10K

I would advise you not to do this. If you anticipate the need for more glow than 30 seconds, depending on the ambient temperature, simply turn the key back to the 0 position and then turn it back to the #2 position to recycle the relay and give you another 40 seconds of glow time. Then start the engine.