[Closed] Truvativ Bottom Bracket Maintenance

I'm stripping down my cheap MTB for the first time (after 8 years) and wanted some advice about whether to open up the BB or leave alone. I have a Truvativ Isoflow crankset (3 chainring 9 spd) - its the cheapest one they do from what I can tell.

As I said, I've never done anything to it and it seems to be turning well when I spin the pedals with the chain off. But maybe it needs a look to see whats going on in there and to put some grease in.

However, I haven't a clue what the BB is and whether it is serviceable. Is there any downside to taking it apart ? If I find its had it - what cheap BB could I replace it with (I don't need anything expensive, because as I said, cheap bike, cheap crankset, but I'd like to keep it going for a while).

Thanks in advance