The ol' 240D just ain't what she used to be. My son has driving my ol' 240D. Fall hit and it doesn't want to start.

I have an "interim" motor in the car which is a serial glow plug motor. When the temp went to the thirties, it wouldn't start. When the temp hit 60 F yesterday, I managed to get it started to bring it home. After getting it home and at operating temperature, sitting for five minutes, I had to glow plug the heck out of it to start it again to move it. The old engine is really tired. As soon as I can, I'm going to do a compression check to see if I can patch the old motor, and squeeze just a little more winter life out of it.

If this were a parallel glow plug engine, I would have already replaced the glow plugs. I had a serial glow plug engine one time that I took them out and cleaned the bores pretty well and replaced the plugs. It was still difficult to start but got by.

My question is, is it necessary to replace these plugs? All they are is a heavy filament. It just seems that as long as they're not open, they should work okay, if everything else is okay. I know they're getting voltage, and the voltage is divided evenly across them. The issue is the plugs, the plug bores and the compression.

Is there anything to gain by replacing these loop type plugs?

Have a great day and thanks for the help,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles