Hi I recently purchased a Volvo v70 with some minor things I like to get sorted, and I hope someone would be kind to assist me with these issue

The glow light in the dash is not appearing at all. But when I have the ignition in position 2, and wait til the srs light dissapear (approx 10 sec) the engine fires up right away. Is there something that I can check myself? Is it common when one or more glow plugs is bad I get No glow plug light? Also when the car has been running just 2 min or so and sits for 5-10 minutes, it is hard to start and when it coughs into life, much black smoke is spotted, even if I waith for 10 seconds with the ignition in pos 2.

Any help would be appreciated