Hey

My volvo 850 has some weird problem and I'm looking for help. Tried to start the engine didn't start (sometimes it wont start the first go) tried second time failed again and I noticed that something was making noise in the engine. Tried to start again but it could not start this time I quess. Turned off the power but the noise was still there. It only stopped when I disconnect the power from the battery.

Now when I connect the battery the noise start right away and only stop when I kill the battery. Any suggestions of the problem? I made a small video from it, the sound quality is bad, its more like a drilling sound and comes somewhere from the engine not in the front fan.

Link to video:

 

It sounds pretty loud almost like the engine is running
From the description I would of suggested the IAC, idle air control but they can't make that much noise.
When it's making that noise can you see if the serpentine belt is moving ??

If it's turning, can you get to the starter to disconnect it ??

You might have a bad ignition switch that's keeping the starter engaged but not sending power to the coil.