I replaced all glow plugs in my 84 300D last winter. With the cold weather we have had recently I have been going through three glow cycles that are extended maybe ten seconds after the light goes out then starting the car. I had the first glow plug failuer last week (no GP light) I found the #1 PG to be bad and replaced it. I now have no glow plug light again but haven't had time to check it out. I need to know if these extended glows are killing the plugs or if this is just a fluke?

Thanks,

Mike