Glow Plugs Stay On After Start - 350SDL
 

Have reviewed applicable threads, but can't find anything quite like my problem. Would appreciate help.

Live in northern Virginia ... getting cool, now. On key-on, glow plug lamp illuminates, then goes out ... seems like a normal start (I replaced plugs a couple of years ago). About as smoky as it has always been. Glow plug lamp goes out.

After about 10 seconds the glow plug lamp re-illuminates and stays on for almost exactly 60 seconds ... very consistent - not engine speed or outside air temperate related. If I turn engine off (whether I pull key to restart or now), the restart sequence is abnormal in that glow plug lamp never illuminates at all.

If car sits for a few hours, the cold start sequence described above occurs, again.

Remainder of operation is normal ... glow plug lamp DOES NOT illuminate while normally driving ... i.e. no intermittent operation, just during post start sequence.

What say the assembled?

Thanks!

The glow plug relay in your car will keep the plugs glowing for a few seconds after a cold start but not for 60 seconds and the glow light shouldn't register after then engine starts. I think the light serves as a fault indicator in this case.

Check the resistance of each glow plug as a start.

Sixto
95 S420
87 300SDL

Thanks, Sixto ... would agree about fault indicator ... would one plug going out cause relay (based on temperature, right?) to go off then come back on?