[utiadam]

It may not be the oil filter housing at all. Do you see that diamond shape cover right above the belt tensioner? That cover has a seal behind it and that will create a leak but usually while driving when oil pressure is built up, the belt itself will fling the oil everywhere.

 

[utiadam]

i dont think the plastic cap is the problem, i've broken one before and it leaves a pretty good size crack at the base of the housing.

 

[utiadam]

good point, i would start by getting some brake clean or engine degreaser and cleaning off the current oil. Once you do that drive for a little while and see if you are able to point out the source of the leak.