Computer running hot after short period

After using Ifixit for several mobile phone repairs I've decided I need to work on my Mac (big breath.)

Mine was one of the recall models and I got it in for the recall. However I know the fans run very warm on this model . I've downloaded Hdd Fan control and have this continuously running but by my own admission its in a poorly lit, badly ventilated, smoky, pet house-room.

Bad conditions for a mac! I do try and gently clean the vents underneath and at the top rear, with a vacuum however is it worth dismantling and "gently" cleaning to get the day to day yuck out of it.

Is there anything I can do help the fan i.e. replace with an uprated after market model to help the ventilation.

Any help or user guides would be greatly ppreciated