I believe both fans that are on back of my computer are exhaust fans.
I would rather not install a new heatsink and just rather by 1 or 2 fans.
I have some pictures below to show you what my case and fans look like.
Thanx for your help so far.
PS: Is 55C on a CPU after strenous work (eg gaming) bad? Am i even need of a fan?
Pic of back of my case with the 2 fans:
Side of case without panel:
Same side with panel (as you can see no holes for fans)
Other side of case without panel:
Same side with panel: