depending on your vehicle, the housing is whear your oil filter screws into. remove oil filter and thi should reveal 3 or 4 bolts in the side of housing remove bolts should come off no problems replace seal behind housing reverse process
check that the O ring was replaced when oil filter was changed. id O ring is good and filter is tight, and housing still leaking, replace filter housing
Which filter housing? Air filter, oil filter, fuel filter?
Open the oil drain plug, drain the oil, remove the oil filter(s), install the new oil filter(s) (remember to replace the rubber grommet in the filter housing, as well), replace the drain plug, refill the oil.
Oil filter
REMOVE THE DRAIN PLUG AND PULL THE FILTER OUT OF THE HOUSING.
Replace the gasket with a new one.
Remove the 4 screws from the rock guard on the front of the engine. Using a universal oil filter wrench, turn the filter housing counter-clockwise until loose then remove by hand. Replace the o-ring in the housing cap and replace the filter inside the housing. I had luck placing he filter into the base on the engine first and then placing the housing cap onto it. Tighten and replace rock shield... Good Luck!!
replace the housing o ring
Take the 4-10mm nuts off the plastic shroud, remove shroud. With a oil filter wrench (or by hand) unscrew (CCW) filter housing. Remove paper filter discard, insert new filter, replace large o-ring on filter housing, screw housing back on till it bottoms out. Replace shroud, tighten 4-10mm nuts. Dispose of filter properly
If it is where the filter meets up to the mount there actually is a gasket there. If it past the mount you may need to replace the filter housing.
take the filter off then unscrew the bolt at the oil filter housing
inside the oil filter housing