Hey, guys--

I have an 1986 300SDL which runs beautifully with few exceptions. One of which is that the glow plugs seem to work intermittently. When I turn the key to the "on" position, the 5 second buzz always occurs, but the dash glow plug light comes on only occasionally. If the light does come on, the car will start easily. If the light doesn't, it's a pain in the neck to start and may take several tries, while blowing big black clouds of smoke. Any ideas how to ensure that the glow plugs always work?

Thanks.

You may have a glow plug or plugs that are failing. I would have them checked. Also, there is a fuse in the glow relay that could have a small crack in it. If it does, replace it...

Good luck