No Problem..... Thanks for the help.
I am rather clumsy so my luck would be dropping the hot glow plug into my lap while it is on.

What if a glow plug is partially bad ? Would it still light up ?

Kamil,

You can test GP with a digital ohmeter. They should read about 0.5 to 0.9 ohms. Remove the GP cable plug from the GP relay and you can test by plugging ohmeter into connector holes. You have to remove connector anyway or you will get parallel readings which are innacurate.

This is an easy test because you don't have to remove the GP. It will find a bad GP 99 out of 100 times.

Do a search on ohmeter and you should get more test instructions.

P E H

The original series loop plugs used on Mercedes diesels up thru the late '70s on most models lasted 75-100kmi. The parallel, rapid heat plugs introducted on the "S" class diesels in the late '70sm and in all the models in 1980 typically last 150-250kmi and occasionally longer. The introduction of extended glow after the engine started in the late '80s started the trend to reduced longevity, but this was largely a factor on the duration of the afterglow - 16 secs on early models with the feature extending to up to 3 minutes on the later indirect injection diesels. The plugs in OM606 engines typically last 40-100kmi but a few last longer and a few will of course fail prematurely.

The numbers I quote assume that OEM (Bosch/Beru) plugs are used. Other aftermarket plugs have exhibited MUCH shorter live in my experience (often months rather than many years).

Marshall

They'll last a long time if you keep the fuel clean and dry. A drippy injector is a death sentence to a glow plug.